Merge branch 'mplegendre-multi_pkgsrc_roots' into develop

- This moves var/spack/packages to var/spack/repos/builtin/packages.

- Packages that did not exist in the source branch, or were changed in
  develop, were moved into var/spack/repos/builtin/packages as part of
  the integration.

Conflicts:
	lib/spack/spack/test/unit_install.py
	var/spack/repos/builtin/packages/clang/package.py

91 files changed, 6903 insertions, 844 deletions

diff --git a/lib/spack/external/argparse.py b/lib/spack/external/argparse.py
index 394e5da152..ec9a9ee738 100644
--- a/lib/spack/external/argparse.py
+++ b/lib/spack/external/argparse.py
@@ -1067,9 +1067,13 @@ class _SubParsersAction(Action):
 
     class _ChoicesPseudoAction(Action):
 
-        def __init__(self, name, help):
+        def __init__(self, name, aliases, help):
+            metavar = dest = name
+            if aliases:
+                metavar += ' (%s)' % ', '.join(aliases)
             sup = super(_SubParsersAction._ChoicesPseudoAction, self)
-            sup.__init__(option_strings=[], dest=name, help=help)
+            sup.__init__(option_strings=[], dest=dest, help=help,
+                         metavar=metavar)
 
     def __init__(self,
                  option_strings,
@@ -1097,15 +1101,22 @@ class _SubParsersAction(Action):
         if kwargs.get('prog') is None:
             kwargs['prog'] = '%s %s' % (self._prog_prefix, name)
 
+        aliases = kwargs.pop('aliases', ())
+
         # create a pseudo-action to hold the choice help
         if 'help' in kwargs:
             help = kwargs.pop('help')
-            choice_action = self._ChoicesPseudoAction(name, help)
+            choice_action = self._ChoicesPseudoAction(name, aliases, help)
             self._choices_actions.append(choice_action)
 
         # create the parser and add it to the map
         parser = self._parser_class(**kwargs)
         self._name_parser_map[name] = parser
+
+        # make parser available under aliases also
+        for alias in aliases:
+            self._name_parser_map[alias] = parser
+
         return parser
 
     def _get_subactions(self):
@@ -1123,8 +1134,9 @@ class _SubParsersAction(Action):
         try:
             parser = self._name_parser_map[parser_name]
         except KeyError:
-            tup = parser_name, ', '.join(self._name_parser_map)
-            msg = _('unknown parser %r (choices: %s)' % tup)
+            args = {'parser_name': parser_name,
+                    'choices': ', '.join(self._name_parser_map)}
+            msg = _('unknown parser %(parser_name)r (choices: %(choices)s)') % args
             raise ArgumentError(self, msg)
 
         # parse all the remaining options into the namespace
diff --git a/lib/spack/external/jsonschema/COPYING b/lib/spack/external/jsonschema/COPYING
new file mode 100644
index 0000000000..af9cfbdb13
--- /dev/null
+++ b/lib/spack/external/jsonschema/COPYING
@@ -0,0 +1,19 @@
+Copyright (c) 2013 Julian Berman
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/lib/spack/external/jsonschema/README.rst b/lib/spack/external/jsonschema/README.rst
new file mode 100644
index 0000000000..20c2fe6266
--- /dev/null
+++ b/lib/spack/external/jsonschema/README.rst
@@ -0,0 +1,104 @@
+==========
+jsonschema
+==========
+
+``jsonschema`` is an implementation of `JSON Schema <http://json-schema.org>`_
+for Python (supporting 2.6+ including Python 3).
+
+.. code-block:: python
+
+    >>> from jsonschema import validate
+
+    >>> # A sample schema, like what we'd get from json.load()
+    >>> schema = {
+    ...     "type" : "object",
+    ...     "properties" : {
+    ...         "price" : {"type" : "number"},
+    ...         "name" : {"type" : "string"},
+    ...     },
+    ... }
+
+    >>> # If no exception is raised by validate(), the instance is valid.
+    >>> validate({"name" : "Eggs", "price" : 34.99}, schema)
+
+    >>> validate(
+    ...     {"name" : "Eggs", "price" : "Invalid"}, schema
+    ... )                                   # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+        ...
+    ValidationError: 'Invalid' is not of type 'number'
+
+
+Features
+--------
+
+* Full support for
+  `Draft 3 <https://python-jsonschema.readthedocs.org/en/latest/validate/#jsonschema.Draft3Validator>`_
+  **and** `Draft 4 <https://python-jsonschema.readthedocs.org/en/latest/validate/#jsonschema.Draft4Validator>`_
+  of the schema.
+
+* `Lazy validation <https://python-jsonschema.readthedocs.org/en/latest/validate/#jsonschema.IValidator.iter_errors>`_
+  that can iteratively report *all* validation errors.
+
+* Small and extensible
+
+* `Programmatic querying <https://python-jsonschema.readthedocs.org/en/latest/errors/#module-jsonschema>`_
+  of which properties or items failed validation.
+
+
+Release Notes
+-------------
+
+* A simple CLI was added for validation
+* Validation errors now keep full absolute paths and absolute schema paths in
+  their ``absolute_path`` and ``absolute_schema_path`` attributes. The ``path``
+  and ``schema_path`` attributes are deprecated in favor of ``relative_path``
+  and ``relative_schema_path``\ .
+
+*Note:* Support for Python 3.2 was dropped in this release, and installation
+now uses setuptools.
+
+
+Running the Test Suite
+----------------------
+
+``jsonschema`` uses the wonderful `Tox <http://tox.readthedocs.org>`_ for its
+test suite. (It really is wonderful, if for some reason you haven't heard of
+it, you really should use it for your projects).
+
+Assuming you have ``tox`` installed (perhaps via ``pip install tox`` or your
+package manager), just run ``tox`` in the directory of your source checkout to
+run ``jsonschema``'s test suite on all of the versions of Python ``jsonschema``
+supports. Note that you'll need to have all of those versions installed in
+order to run the tests on each of them, otherwise ``tox`` will skip (and fail)
+the tests on that version.
+
+Of course you're also free to just run the tests on a single version with your
+favorite test runner. The tests live in the ``jsonschema.tests`` package.
+
+
+Community
+---------
+
+There's a `mailing list <https://groups.google.com/forum/#!forum/jsonschema>`_
+for this implementation on Google Groups.
+
+Please join, and feel free to send questions there.
+
+
+Contributing
+------------
+
+I'm Julian Berman.
+
+``jsonschema`` is on `GitHub <http://github.com/Julian/jsonschema>`_.
+
+Get in touch, via GitHub or otherwise, if you've got something to contribute,
+it'd be most welcome!
+
+You can also generally find me on Freenode (nick: ``tos9``) in various
+channels, including ``#python``.
+
+If you feel overwhelmingly grateful, you can woo me with beer money on
+`Gittip <https://www.gittip.com/Julian/>`_ or via Google Wallet with the email
+in my GitHub profile.
diff --git a/lib/spack/external/jsonschema/__init__.py b/lib/spack/external/jsonschema/__init__.py
new file mode 100644
index 0000000000..6c099f1d8b
--- /dev/null
+++ b/lib/spack/external/jsonschema/__init__.py
@@ -0,0 +1,26 @@
+"""
+An implementation of JSON Schema for Python
+
+The main functionality is provided by the validator classes for each of the
+supported JSON Schema versions.
+
+Most commonly, :func:`validate` is the quickest way to simply validate a given
+instance under a schema, and will create a validator for you.
+
+"""
+
+from jsonschema.exceptions import (
+    ErrorTree, FormatError, RefResolutionError, SchemaError, ValidationError
+)
+from jsonschema._format import (
+    FormatChecker, draft3_format_checker, draft4_format_checker,
+)
+from jsonschema.validators import (
+    Draft3Validator, Draft4Validator, RefResolver, validate
+)
+
+
+__version__ = "2.4.0"
+
+
+# flake8: noqa
diff --git a/lib/spack/external/jsonschema/__main__.py b/lib/spack/external/jsonschema/__main__.py
new file mode 100644
index 0000000000..82c29fd39e
--- /dev/null
+++ b/lib/spack/external/jsonschema/__main__.py
@@ -0,0 +1,2 @@
+from jsonschema.cli import main
+main()
diff --git a/lib/spack/external/jsonschema/_format.py b/lib/spack/external/jsonschema/_format.py
new file mode 100644
index 0000000000..bb52d183ad
--- /dev/null
+++ b/lib/spack/external/jsonschema/_format.py
@@ -0,0 +1,240 @@
+import datetime
+import re
+import socket
+
+from jsonschema.compat import str_types
+from jsonschema.exceptions import FormatError
+
+
+class FormatChecker(object):
+    """
+    A ``format`` property checker.
+
+    JSON Schema does not mandate that the ``format`` property actually do any
+    validation. If validation is desired however, instances of this class can
+    be hooked into validators to enable format validation.
+
+    :class:`FormatChecker` objects always return ``True`` when asked about
+    formats that they do not know how to validate.
+
+    To check a custom format using a function that takes an instance and
+    returns a ``bool``, use the :meth:`FormatChecker.checks` or
+    :meth:`FormatChecker.cls_checks` decorators.
+
+    :argument iterable formats: the known formats to validate. This argument
+                                can be used to limit which formats will be used
+                                during validation.
+
+    """
+
+    checkers = {}
+
+    def __init__(self, formats=None):
+        if formats is None:
+            self.checkers = self.checkers.copy()
+        else:
+            self.checkers = dict((k, self.checkers[k]) for k in formats)
+
+    def checks(self, format, raises=()):
+        """
+        Register a decorated function as validating a new format.
+
+        :argument str format: the format that the decorated function will check
+        :argument Exception raises: the exception(s) raised by the decorated
+            function when an invalid instance is found. The exception object
+            will be accessible as the :attr:`ValidationError.cause` attribute
+            of the resulting validation error.
+
+        """
+
+        def _checks(func):
+            self.checkers[format] = (func, raises)
+            return func
+        return _checks
+
+    cls_checks = classmethod(checks)
+
+    def check(self, instance, format):
+        """
+        Check whether the instance conforms to the given format.
+
+        :argument instance: the instance to check
+        :type: any primitive type (str, number, bool)
+        :argument str format: the format that instance should conform to
+        :raises: :exc:`FormatError` if instance does not conform to format
+
+        """
+
+        if format not in self.checkers:
+            return
+
+        func, raises = self.checkers[format]
+        result, cause = None, None
+        try:
+            result = func(instance)
+        except raises as e:
+            cause = e
+        if not result:
+            raise FormatError(
+                "%r is not a %r" % (instance, format), cause=cause,
+            )
+
+    def conforms(self, instance, format):
+        """
+        Check whether the instance conforms to the given format.
+
+        :argument instance: the instance to check
+        :type: any primitive type (str, number, bool)
+        :argument str format: the format that instance should conform to
+        :rtype: bool
+
+        """
+
+        try:
+            self.check(instance, format)
+        except FormatError:
+            return False
+        else:
+            return True
+
+
+_draft_checkers = {"draft3": [], "draft4": []}
+
+
+def _checks_drafts(both=None, draft3=None, draft4=None, raises=()):
+    draft3 = draft3 or both
+    draft4 = draft4 or both
+
+    def wrap(func):
+        if draft3:
+            _draft_checkers["draft3"].append(draft3)
+            func = FormatChecker.cls_checks(draft3, raises)(func)
+        if draft4:
+            _draft_checkers["draft4"].append(draft4)
+            func = FormatChecker.cls_checks(draft4, raises)(func)
+        return func
+    return wrap
+
+
+@_checks_drafts("email")
+def is_email(instance):
+    if not isinstance(instance, str_types):
+        return True
+    return "@" in instance
+
+
+_ipv4_re = re.compile(r"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$")
+
+@_checks_drafts(draft3="ip-address", draft4="ipv4")
+def is_ipv4(instance):
+    if not isinstance(instance, str_types):
+        return True
+    if not _ipv4_re.match(instance):
+        return False
+    return all(0 <= int(component) <= 255 for component in instance.split("."))
+
+
+if hasattr(socket, "inet_pton"):
+    @_checks_drafts("ipv6", raises=socket.error)
+    def is_ipv6(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return socket.inet_pton(socket.AF_INET6, instance)
+
+
+_host_name_re = re.compile(r"^[A-Za-z0-9][A-Za-z0-9\.\-]{1,255}$")
+
+@_checks_drafts(draft3="host-name", draft4="hostname")
+def is_host_name(instance):
+    if not isinstance(instance, str_types):
+        return True
+    if not _host_name_re.match(instance):
+        return False
+    components = instance.split(".")
+    for component in components:
+        if len(component) > 63:
+            return False
+    return True
+
+
+try:
+    import rfc3987
+except ImportError:
+    pass
+else:
+    @_checks_drafts("uri", raises=ValueError)
+    def is_uri(instance):
+        if not isinstance(instance, str_types):
+            return True
+        return rfc3987.parse(instance, rule="URI")
+
+
+try:
+    import strict_rfc3339
+except ImportError:
+    try:
+        import isodate
+    except ImportError:
+        pass
+    else:
+        @_checks_drafts("date-time", raises=(ValueError, isodate.ISO8601Error))
+        def is_date(instance):
+            if not isinstance(instance, str_types):
+                return True
+            return isodate.parse_datetime(instance)
+else:
+        @_checks_drafts("date-time")
+        def is_date(instance):
+            if not isinstance(instance, str_types):
+                return True
+            return strict_rfc3339.validate_rfc3339(instance)
+
+
+@_checks_drafts("regex", raises=re.error)
+def is_regex(instance):
+    if not isinstance(instance, str_types):
+        return True
+    return re.compile(instance)
+
+
+@_checks_drafts(draft3="date", raises=ValueError)
+def is_date(instance):
+    if not isinstance(instance, str_types):
+        return True
+    return datetime.datetime.strptime(instance, "%Y-%m-%d")
+
+
+@_checks_drafts(draft3="time", raises=ValueError)
+def is_time(instance):
+    if not isinstance(instance, str_types):
+        return True
+    return datetime.datetime.strptime(instance, "%H:%M:%S")
+
+
+try:
+    import webcolors
+except ImportError:
+    pass
+else:
+    def is_css_color_code(instance):
+        return webcolors.normalize_hex(instance)
+
+
+    @_checks_drafts(draft3="color", raises=(ValueError, TypeError))
+    def is_css21_color(instance):
+        if (
+            not isinstance(instance, str_types) or
+            instance.lower() in webcolors.css21_names_to_hex
+        ):
+            return True
+        return is_css_color_code(instance)
+
+
+    def is_css3_color(instance):
+        if instance.lower() in webcolors.css3_names_to_hex:
+            return True
+        return is_css_color_code(instance)
+
+
+draft3_format_checker = FormatChecker(_draft_checkers["draft3"])
+draft4_format_checker = FormatChecker(_draft_checkers["draft4"])
diff --git a/lib/spack/external/jsonschema/_reflect.py b/lib/spack/external/jsonschema/_reflect.py
new file mode 100644
index 0000000000..d09e38fbdc
--- /dev/null
+++ b/lib/spack/external/jsonschema/_reflect.py
@@ -0,0 +1,155 @@
+# -*- test-case-name: twisted.test.test_reflect -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Standardized versions of various cool and/or strange things that you can do
+with Python's reflection capabilities.
+"""
+
+import sys
+
+from jsonschema.compat import PY3
+
+
+class _NoModuleFound(Exception):
+    """
+    No module was found because none exists.
+    """
+
+
+
+class InvalidName(ValueError):
+    """
+    The given name is not a dot-separated list of Python objects.
+    """
+
+
+
+class ModuleNotFound(InvalidName):
+    """
+    The module associated with the given name doesn't exist and it can't be
+    imported.
+    """
+
+
+
+class ObjectNotFound(InvalidName):
+    """
+    The object associated with the given name doesn't exist and it can't be
+    imported.
+    """
+
+
+
+if PY3:
+    def reraise(exception, traceback):
+        raise exception.with_traceback(traceback)
+else:
+    exec("""def reraise(exception, traceback):
+        raise exception.__class__, exception, traceback""")
+
+reraise.__doc__ = """
+Re-raise an exception, with an optional traceback, in a way that is compatible
+with both Python 2 and Python 3.
+
+Note that on Python 3, re-raised exceptions will be mutated, with their
+C{__traceback__} attribute being set.
+
+@param exception: The exception instance.
+@param traceback: The traceback to use, or C{None} indicating a new traceback.
+"""
+
+
+def _importAndCheckStack(importName):
+    """
+    Import the given name as a module, then walk the stack to determine whether
+    the failure was the module not existing, or some code in the module (for
+    example a dependent import) failing.  This can be helpful to determine
+    whether any actual application code was run.  For example, to distiguish
+    administrative error (entering the wrong module name), from programmer
+    error (writing buggy code in a module that fails to import).
+
+    @param importName: The name of the module to import.
+    @type importName: C{str}
+    @raise Exception: if something bad happens.  This can be any type of
+        exception, since nobody knows what loading some arbitrary code might
+        do.
+    @raise _NoModuleFound: if no module was found.
+    """
+    try:
+        return __import__(importName)
+    except ImportError:
+        excType, excValue, excTraceback = sys.exc_info()
+        while excTraceback:
+            execName = excTraceback.tb_frame.f_globals["__name__"]
+            # in Python 2 execName is None when an ImportError is encountered,
+            # where in Python 3 execName is equal to the importName.
+            if execName is None or execName == importName:
+                reraise(excValue, excTraceback)
+            excTraceback = excTraceback.tb_next
+        raise _NoModuleFound()
+
+
+
+def namedAny(name):
+    """
+    Retrieve a Python object by its fully qualified name from the global Python
+    module namespace.  The first part of the name, that describes a module,
+    will be discovered and imported.  Each subsequent part of the name is
+    treated as the name of an attribute of the object specified by all of the
+    name which came before it.  For example, the fully-qualified name of this
+    object is 'twisted.python.reflect.namedAny'.
+
+    @type name: L{str}
+    @param name: The name of the object to return.
+
+    @raise InvalidName: If the name is an empty string, starts or ends with
+        a '.', or is otherwise syntactically incorrect.
+
+    @raise ModuleNotFound: If the name is syntactically correct but the
+        module it specifies cannot be imported because it does not appear to
+        exist.
+
+    @raise ObjectNotFound: If the name is syntactically correct, includes at
+        least one '.', but the module it specifies cannot be imported because
+        it does not appear to exist.
+
+    @raise AttributeError: If an attribute of an object along the way cannot be
+        accessed, or a module along the way is not found.
+
+    @return: the Python object identified by 'name'.
+    """
+    if not name:
+        raise InvalidName('Empty module name')
+
+    names = name.split('.')
+
+    # if the name starts or ends with a '.' or contains '..', the __import__
+    # will raise an 'Empty module name' error. This will provide a better error
+    # message.
+    if '' in names:
+        raise InvalidName(
+            "name must be a string giving a '.'-separated list of Python "
+            "identifiers, not %r" % (name,))
+
+    topLevelPackage = None
+    moduleNames = names[:]
+    while not topLevelPackage:
+        if moduleNames:
+            trialname = '.'.join(moduleNames)
+            try:
+                topLevelPackage = _importAndCheckStack(trialname)
+            except _NoModuleFound:
+                moduleNames.pop()
+        else:
+            if len(names) == 1:
+                raise ModuleNotFound("No module named %r" % (name,))
+            else:
+                raise ObjectNotFound('%r does not name an object' % (name,))
+
+    obj = topLevelPackage
+    for n in names[1:]:
+        obj = getattr(obj, n)
+
+    return obj
diff --git a/lib/spack/external/jsonschema/_utils.py b/lib/spack/external/jsonschema/_utils.py
new file mode 100644
index 0000000000..2262f3305d
--- /dev/null
+++ b/lib/spack/external/jsonschema/_utils.py
@@ -0,0 +1,213 @@
+import itertools
+import json
+import pkgutil
+import re
+
+from jsonschema.compat import str_types, MutableMapping, urlsplit
+
+
+class URIDict(MutableMapping):
+    """
+    Dictionary which uses normalized URIs as keys.
+
+    """
+
+    def normalize(self, uri):
+        return urlsplit(uri).geturl()
+
+    def __init__(self, *args, **kwargs):
+        self.store = dict()
+        self.store.update(*args, **kwargs)
+
+    def __getitem__(self, uri):
+        return self.store[self.normalize(uri)]
+
+    def __setitem__(self, uri, value):
+        self.store[self.normalize(uri)] = value
+
+    def __delitem__(self, uri):
+        del self.store[self.normalize(uri)]
+
+    def __iter__(self):
+        return iter(self.store)
+
+    def __len__(self):
+        return len(self.store)
+
+    def __repr__(self):
+        return repr(self.store)
+
+
+class Unset(object):
+    """
+    An as-of-yet unset attribute or unprovided default parameter.
+
+    """
+
+    def __repr__(self):
+        return "<unset>"
+
+
+def load_schema(name):
+    """
+    Load a schema from ./schemas/``name``.json and return it.
+
+    """
+
+    data = pkgutil.get_data(__package__, "schemas/{0}.json".format(name))
+    return json.loads(data.decode("utf-8"))
+
+
+def indent(string, times=1):
+    """
+    A dumb version of :func:`textwrap.indent` from Python 3.3.
+
+    """
+
+    return "\n".join(" " * (4 * times) + line for line in string.splitlines())
+
+
+def format_as_index(indices):
+    """
+    Construct a single string containing indexing operations for the indices.
+
+    For example, [1, 2, "foo"] -> [1][2]["foo"]
+
+    :type indices: sequence
+
+    """
+
+    if not indices:
+        return ""
+    return "[%s]" % "][".join(repr(index) for index in indices)
+
+
+def find_additional_properties(instance, schema):
+    """
+    Return the set of additional properties for the given ``instance``.
+
+    Weeds out properties that should have been validated by ``properties`` and
+    / or ``patternProperties``.
+
+    Assumes ``instance`` is dict-like already.
+
+    """
+
+    properties = schema.get("properties", {})
+    patterns = "|".join(schema.get("patternProperties", {}))
+    for property in instance:
+        if property not in properties:
+            if patterns and re.search(patterns, property):
+                continue
+            yield property
+
+
+def extras_msg(extras):
+    """
+    Create an error message for extra items or properties.
+
+    """
+
+    if len(extras) == 1:
+        verb = "was"
+    else:
+        verb = "were"
+    return ", ".join(repr(extra) for extra in extras), verb
+
+
+def types_msg(instance, types):
+    """
+    Create an error message for a failure to match the given types.
+
+    If the ``instance`` is an object and contains a ``name`` property, it will
+    be considered to be a description of that object and used as its type.
+
+    Otherwise the message is simply the reprs of the given ``types``.
+
+    """
+
+    reprs = []
+    for type in types:
+        try:
+            reprs.append(repr(type["name"]))
+        except Exception:
+            reprs.append(repr(type))
+    return "%r is not of type %s" % (instance, ", ".join(reprs))
+
+
+def flatten(suitable_for_isinstance):
+    """
+    isinstance() can accept a bunch of really annoying different types:
+        * a single type
+        * a tuple of types
+        * an arbitrary nested tree of tuples
+
+    Return a flattened tuple of the given argument.
+
+    """
+
+    types = set()
+
+    if not isinstance(suitable_for_isinstance, tuple):
+        suitable_for_isinstance = (suitable_for_isinstance,)
+    for thing in suitable_for_isinstance:
+        if isinstance(thing, tuple):
+            types.update(flatten(thing))
+        else:
+            types.add(thing)
+    return tuple(types)
+
+
+def ensure_list(thing):
+    """
+    Wrap ``thing`` in a list if it's a single str.
+
+    Otherwise, return it unchanged.
+
+    """
+
+    if isinstance(thing, str_types):
+        return [thing]
+    return thing
+
+
+def unbool(element, true=object(), false=object()):
+    """
+    A hack to make True and 1 and False and 0 unique for ``uniq``.
+
+    """
+
+    if element is True:
+        return true
+    elif element is False:
+        return false
+    return element
+
+
+def uniq(container):
+    """
+    Check if all of a container's elements are unique.
+
+    Successively tries first to rely that the elements are hashable, then
+    falls back on them being sortable, and finally falls back on brute
+    force.
+
+    """
+
+    try:
+        return len(set(unbool(i) for i in container)) == len(container)
+    except TypeError:
+        try:
+            sort = sorted(unbool(i) for i in container)
+            sliced = itertools.islice(sort, 1, None)
+            for i, j in zip(sort, sliced):
+                if i == j:
+                    return False
+        except (NotImplementedError, TypeError):
+            seen = []
+            for e in container:
+                e = unbool(e)
+                if e in seen:
+                    return False
+                seen.append(e)
+    return True
diff --git a/lib/spack/external/jsonschema/_validators.py b/lib/spack/external/jsonschema/_validators.py
new file mode 100644
index 0000000000..c6e801ccb2
--- /dev/null
+++ b/lib/spack/external/jsonschema/_validators.py
@@ -0,0 +1,358 @@
+import re
+
+from jsonschema import _utils
+from jsonschema.exceptions import FormatError, ValidationError
+from jsonschema.compat import iteritems
+
+
+FLOAT_TOLERANCE = 10 ** -15
+
+
+def patternProperties(validator, patternProperties, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+
+    for pattern, subschema in iteritems(patternProperties):
+        for k, v in iteritems(instance):
+            if re.search(pattern, k):
+                for error in validator.descend(
+                    v, subschema, path=k, schema_path=pattern,
+                ):
+                    yield error
+
+
+def additionalProperties(validator, aP, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+
+    extras = set(_utils.find_additional_properties(instance, schema))
+
+    if validator.is_type(aP, "object"):
+        for extra in extras:
+            for error in validator.descend(instance[extra], aP, path=extra):
+                yield error
+    elif not aP and extras:
+        error = "Additional properties are not allowed (%s %s unexpected)"
+        yield ValidationError(error % _utils.extras_msg(extras))
+
+
+def items(validator, items, instance, schema):
+    if not validator.is_type(instance, "array"):
+        return
+
+    if validator.is_type(items, "object"):
+        for index, item in enumerate(instance):
+            for error in validator.descend(item, items, path=index):
+                yield error
+    else:
+        for (index, item), subschema in zip(enumerate(instance), items):
+            for error in validator.descend(
+                item, subschema, path=index, schema_path=index,
+            ):
+                yield error
+
+
+def additionalItems(validator, aI, instance, schema):
+    if (
+        not validator.is_type(instance, "array") or
+        validator.is_type(schema.get("items", {}), "object")
+    ):
+        return
+
+    len_items = len(schema.get("items", []))
+    if validator.is_type(aI, "object"):
+        for index, item in enumerate(instance[len_items:], start=len_items):
+            for error in validator.descend(item, aI, path=index):
+                yield error
+    elif not aI and len(instance) > len(schema.get("items", [])):
+        error = "Additional items are not allowed (%s %s unexpected)"
+        yield ValidationError(
+            error %
+            _utils.extras_msg(instance[len(schema.get("items", [])):])
+        )
+
+
+def minimum(validator, minimum, instance, schema):
+    if not validator.is_type(instance, "number"):
+        return
+
+    if schema.get("exclusiveMinimum", False):
+        failed = float(instance) <= minimum
+        cmp = "less than or equal to"
+    else:
+        failed = float(instance) < minimum
+        cmp = "less than"
+
+    if failed:
+        yield ValidationError(
+            "%r is %s the minimum of %r" % (instance, cmp, minimum)
+        )
+
+
+def maximum(validator, maximum, instance, schema):
+    if not validator.is_type(instance, "number"):
+        return
+
+    if schema.get("exclusiveMaximum", False):
+        failed = instance >= maximum
+        cmp = "greater than or equal to"
+    else:
+        failed = instance > maximum
+        cmp = "greater than"
+
+    if failed:
+        yield ValidationError(
+            "%r is %s the maximum of %r" % (instance, cmp, maximum)
+        )
+
+
+def multipleOf(validator, dB, instance, schema):
+    if not validator.is_type(instance, "number"):
+        return
+
+    if isinstance(dB, float):
+        mod = instance % dB
+        failed = (mod > FLOAT_TOLERANCE) and (dB - mod) > FLOAT_TOLERANCE
+    else:
+        failed = instance % dB
+
+    if failed:
+        yield ValidationError("%r is not a multiple of %r" % (instance, dB))
+
+
+def minItems(validator, mI, instance, schema):
+    if validator.is_type(instance, "array") and len(instance) < mI:
+        yield ValidationError("%r is too short" % (instance,))
+
+
+def maxItems(validator, mI, instance, schema):
+    if validator.is_type(instance, "array") and len(instance) > mI:
+        yield ValidationError("%r is too long" % (instance,))
+
+
+def uniqueItems(validator, uI, instance, schema):
+    if (
+        uI and
+        validator.is_type(instance, "array") and
+        not _utils.uniq(instance)
+    ):
+        yield ValidationError("%r has non-unique elements" % instance)
+
+
+def pattern(validator, patrn, instance, schema):
+    if (
+        validator.is_type(instance, "string") and
+        not re.search(patrn, instance)
+    ):
+        yield ValidationError("%r does not match %r" % (instance, patrn))
+
+
+def format(validator, format, instance, schema):
+    if validator.format_checker is not None:
+        try:
+            validator.format_checker.check(instance, format)
+        except FormatError as error:
+            yield ValidationError(error.message, cause=error.cause)
+
+
+def minLength(validator, mL, instance, schema):
+    if validator.is_type(instance, "string") and len(instance) < mL:
+        yield ValidationError("%r is too short" % (instance,))
+
+
+def maxLength(validator, mL, instance, schema):
+    if validator.is_type(instance, "string") and len(instance) > mL:
+        yield ValidationError("%r is too long" % (instance,))
+
+
+def dependencies(validator, dependencies, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+
+    for property, dependency in iteritems(dependencies):
+        if property not in instance:
+            continue
+
+        if validator.is_type(dependency, "object"):
+            for error in validator.descend(
+                instance, dependency, schema_path=property,
+            ):
+                yield error
+        else:
+            dependencies = _utils.ensure_list(dependency)
+            for dependency in dependencies:
+                if dependency not in instance:
+                    yield ValidationError(
+                        "%r is a dependency of %r" % (dependency, property)
+                    )
+
+
+def enum(validator, enums, instance, schema):
+    if instance not in enums:
+        yield ValidationError("%r is not one of %r" % (instance, enums))
+
+
+def ref(validator, ref, instance, schema):
+    with validator.resolver.resolving(ref) as resolved:
+        for error in validator.descend(instance, resolved):
+            yield error
+
+
+def type_draft3(validator, types, instance, schema):
+    types = _utils.ensure_list(types)
+
+    all_errors = []
+    for index, type in enumerate(types):
+        if type == "any":
+            return
+        if validator.is_type(type, "object"):
+            errors = list(validator.descend(instance, type, schema_path=index))
+            if not errors:
+                return
+            all_errors.extend(errors)
+        else:
+            if validator.is_type(instance, type):
+                return
+    else:
+        yield ValidationError(
+            _utils.types_msg(instance, types), context=all_errors,
+        )
+
+
+def properties_draft3(validator, properties, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+
+    for property, subschema in iteritems(properties):
+        if property in instance:
+            for error in validator.descend(
+                instance[property],
+                subschema,
+                path=property,
+                schema_path=property,
+            ):
+                yield error
+        elif subschema.get("required", False):
+            error = ValidationError("%r is a required property" % property)
+            error._set(
+                validator="required",
+                validator_value=subschema["required"],
+                instance=instance,
+                schema=schema,
+            )
+            error.path.appendleft(property)
+            error.schema_path.extend([property, "required"])
+            yield error
+
+
+def disallow_draft3(validator, disallow, instance, schema):
+    for disallowed in _utils.ensure_list(disallow):
+        if validator.is_valid(instance, {"type" : [disallowed]}):
+            yield ValidationError(
+                "%r is disallowed for %r" % (disallowed, instance)
+            )
+
+
+def extends_draft3(validator, extends, instance, schema):
+    if validator.is_type(extends, "object"):
+        for error in validator.descend(instance, extends):
+            yield error
+        return
+    for index, subschema in enumerate(extends):
+        for error in validator.descend(instance, subschema, schema_path=index):
+            yield error
+
+
+def type_draft4(validator, types, instance, schema):
+    types = _utils.ensure_list(types)
+
+    if not any(validator.is_type(instance, type) for type in types):
+        yield ValidationError(_utils.types_msg(instance, types))
+
+
+def properties_draft4(validator, properties, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+
+    for property, subschema in iteritems(properties):
+        if property in instance:
+            for error in validator.descend(
+                instance[property],
+                subschema,
+                path=property,
+                schema_path=property,
+            ):
+                yield error
+
+
+def required_draft4(validator, required, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+    for property in required:
+        if property not in instance:
+            yield ValidationError("%r is a required property" % property)
+
+
+def minProperties_draft4(validator, mP, instance, schema):
+    if validator.is_type(instance, "object") and len(instance) < mP:
+        yield ValidationError(
+            "%r does not have enough properties" % (instance,)
+        )
+
+
+def maxProperties_draft4(validator, mP, instance, schema):
+    if not validator.is_type(instance, "object"):
+        return
+    if validator.is_type(instance, "object") and len(instance) > mP:
+        yield ValidationError("%r has too many properties" % (instance,))
+
+
+def allOf_draft4(validator, allOf, instance, schema):
+    for index, subschema in enumerate(allOf):
+        for error in validator.descend(instance, subschema, schema_path=index):
+            yield error
+
+
+def oneOf_draft4(validator, oneOf, instance, schema):
+    subschemas = enumerate(oneOf)
+    all_errors = []
+    for index, subschema in subschemas:
+        errs = list(validator.descend(instance, subschema, schema_path=index))
+        if not errs:
+            first_valid = subschema
+            break
+        all_errors.extend(errs)
+    else:
+        yield ValidationError(
+            "%r is not valid under any of the given schemas" % (instance,),
+            context=all_errors,
+        )
+
+    more_valid = [s for i, s in subschemas if validator.is_valid(instance, s)]
+    if more_valid:
+        more_valid.append(first_valid)
+        reprs = ", ".join(repr(schema) for schema in more_valid)
+        yield ValidationError(
+            "%r is valid under each of %s" % (instance, reprs)
+        )
+
+
+def anyOf_draft4(validator, anyOf, instance, schema):
+    all_errors = []
+    for index, subschema in enumerate(anyOf):
+        errs = list(validator.descend(instance, subschema, schema_path=index))
+        if not errs:
+            break
+        all_errors.extend(errs)
+    else:
+        yield ValidationError(
+            "%r is not valid under any of the given schemas" % (instance,),
+            context=all_errors,
+        )
+
+
+def not_draft4(validator, not_schema, instance, schema):
+    if validator.is_valid(instance, not_schema):
+        yield ValidationError(
+            "%r is not allowed for %r" % (not_schema, instance)
+        )
diff --git a/lib/spack/external/jsonschema/cli.py b/lib/spack/external/jsonschema/cli.py
new file mode 100644
index 0000000000..0126564f46
--- /dev/null
+++ b/lib/spack/external/jsonschema/cli.py
@@ -0,0 +1,72 @@
+from __future__ import absolute_import
+import argparse
+import json
+import sys
+
+from jsonschema._reflect import namedAny
+from jsonschema.validators import validator_for
+
+
+def _namedAnyWithDefault(name):
+    if "." not in name:
+        name = "jsonschema." + name
+    return namedAny(name)
+
+
+def _json_file(path):
+    with open(path) as file:
+        return json.load(file)
+
+
+parser = argparse.ArgumentParser(
+    description="JSON Schema Validation CLI",
+)
+parser.add_argument(
+    "-i", "--instance",
+    action="append",
+    dest="instances",
+    type=_json_file,
+    help="a path to a JSON instance to validate "
+         "(may be specified multiple times)",
+)
+parser.add_argument(
+    "-F", "--error-format",
+    default="{error.instance}: {error.message}\n",
+    help="the format to use for each error output message, specified in "
+         "a form suitable for passing to str.format, which will be called "
+         "with 'error' for each error",
+)
+parser.add_argument(
+    "-V", "--validator",
+    type=_namedAnyWithDefault,
+    help="the fully qualified object name of a validator to use, or, for "
+         "validators that are registered with jsonschema, simply the name "
+         "of the class.",
+)
+parser.add_argument(
+    "schema",
+    help="the JSON Schema to validate with",
+    type=_json_file,
+)
+
+
+def parse_args(args):
+    arguments = vars(parser.parse_args(args=args or ["--help"]))
+    if arguments["validator"] is None:
+        arguments["validator"] = validator_for(arguments["schema"])
+    return arguments
+
+
+def main(args=sys.argv[1:]):
+    sys.exit(run(arguments=parse_args(args=args)))
+
+
+def run(arguments, stdout=sys.stdout, stderr=sys.stderr):
+    error_format = arguments["error_format"]
+    validator = arguments["validator"](schema=arguments["schema"])
+    errored = False
+    for instance in arguments["instances"] or ():
+        for error in validator.iter_errors(instance):
+            stderr.write(error_format.format(error=error))
+            errored = True
+    return errored
diff --git a/lib/spack/external/jsonschema/compat.py b/lib/spack/external/jsonschema/compat.py
new file mode 100644
index 0000000000..6ca49ab6be
--- /dev/null
+++ b/lib/spack/external/jsonschema/compat.py
@@ -0,0 +1,53 @@
+from __future__ import unicode_literals
+import sys
+import operator
+
+try:
+    from collections import MutableMapping, Sequence  # noqa
+except ImportError:
+    from collections.abc import MutableMapping, Sequence  # noqa
+
+PY3 = sys.version_info[0] >= 3
+
+if PY3:
+    zip = zip
+    from io import StringIO
+    from urllib.parse import (
+        unquote, urljoin, urlunsplit, SplitResult, urlsplit as _urlsplit
+    )
+    from urllib.request import urlopen
+    str_types = str,
+    int_types = int,
+    iteritems = operator.methodcaller("items")
+else:
+    from itertools import izip as zip  # noqa
+    from StringIO import StringIO
+    from urlparse import (
+        urljoin, urlunsplit, SplitResult, urlsplit as _urlsplit # noqa
+    )
+    from urllib import unquote  # noqa
+    from urllib2 import urlopen  # noqa
+    str_types = basestring
+    int_types = int, long
+    iteritems = operator.methodcaller("iteritems")
+
+
+# On python < 3.3 fragments are not handled properly with unknown schemes
+def urlsplit(url):
+    scheme, netloc, path, query, fragment = _urlsplit(url)
+    if "#" in path:
+        path, fragment = path.split("#", 1)
+    return SplitResult(scheme, netloc, path, query, fragment)
+
+
+def urldefrag(url):
+    if "#" in url:
+        s, n, p, q, frag = urlsplit(url)
+        defrag = urlunsplit((s, n, p, q, ''))
+    else:
+        defrag = url
+        frag = ''
+    return defrag, frag
+
+
+# flake8: noqa
diff --git a/lib/spack/external/jsonschema/exceptions.py b/lib/spack/external/jsonschema/exceptions.py
new file mode 100644
index 0000000000..478e59c531
--- /dev/null
+++ b/lib/spack/external/jsonschema/exceptions.py
@@ -0,0 +1,264 @@
+from collections import defaultdict, deque
+import itertools
+import pprint
+import textwrap
+
+from jsonschema import _utils
+from jsonschema.compat import PY3, iteritems
+
+
+WEAK_MATCHES = frozenset(["anyOf", "oneOf"])
+STRONG_MATCHES = frozenset()
+
+_unset = _utils.Unset()
+
+
+class _Error(Exception):
+    def __init__(
+        self,
+        message,
+        validator=_unset,
+        path=(),
+        cause=None,
+        context=(),
+        validator_value=_unset,
+        instance=_unset,
+        schema=_unset,
+        schema_path=(),
+        parent=None,
+    ):
+        self.message = message
+        self.path = self.relative_path = deque(path)
+        self.schema_path = self.relative_schema_path = deque(schema_path)
+        self.context = list(context)
+        self.cause = self.__cause__ = cause
+        self.validator = validator
+        self.validator_value = validator_value
+        self.instance = instance
+        self.schema = schema
+        self.parent = parent
+
+        for error in context:
+            error.parent = self
+
+    def __repr__(self):
+        return "<%s: %r>" % (self.__class__.__name__, self.message)
+
+    def __str__(self):
+        return unicode(self).encode("utf-8")
+
+    def __unicode__(self):
+        essential_for_verbose = (
+            self.validator, self.validator_value, self.instance, self.schema,
+        )
+        if any(m is _unset for m in essential_for_verbose):
+            return self.message
+
+        pschema = pprint.pformat(self.schema, width=72)
+        pinstance = pprint.pformat(self.instance, width=72)
+        return self.message + textwrap.dedent("""
+
+            Failed validating %r in schema%s:
+            %s
+
+            On instance%s:
+            %s
+            """.rstrip()
+        ) % (
+            self.validator,
+            _utils.format_as_index(list(self.relative_schema_path)[:-1]),
+            _utils.indent(pschema),
+            _utils.format_as_index(self.relative_path),
+            _utils.indent(pinstance),
+        )
+
+    if PY3:
+        __str__ = __unicode__
+
+    @classmethod
+    def create_from(cls, other):
+        return cls(**other._contents())
+
+    @property
+    def absolute_path(self):
+        parent = self.parent
+        if parent is None:
+            return self.relative_path
+
+        path = deque(self.relative_path)
+        path.extendleft(parent.absolute_path)
+        return path
+
+    @property
+    def absolute_schema_path(self):
+        parent = self.parent
+        if parent is None:
+            return self.relative_schema_path
+
+        path = deque(self.relative_schema_path)
+        path.extendleft(parent.absolute_schema_path)
+        return path
+
+    def _set(self, **kwargs):
+        for k, v in iteritems(kwargs):
+            if getattr(self, k) is _unset:
+                setattr(self, k, v)
+
+    def _contents(self):
+        attrs = (
+            "message", "cause", "context", "validator", "validator_value",
+            "path", "schema_path", "instance", "schema", "parent",
+        )
+        return dict((attr, getattr(self, attr)) for attr in attrs)
+
+
+class ValidationError(_Error):
+    pass
+
+
+class SchemaError(_Error):
+    pass
+
+
+class RefResolutionError(Exception):
+    pass
+
+
+class UnknownType(Exception):
+    def __init__(self, type, instance, schema):
+        self.type = type
+        self.instance = instance
+        self.schema = schema
+
+    def __str__(self):
+        return unicode(self).encode("utf-8")
+
+    def __unicode__(self):
+        pschema = pprint.pformat(self.schema, width=72)
+        pinstance = pprint.pformat(self.instance, width=72)
+        return textwrap.dedent("""
+            Unknown type %r for validator with schema:
+            %s
+
+            While checking instance:
+            %s
+            """.rstrip()
+        ) % (self.type, _utils.indent(pschema), _utils.indent(pinstance))
+
+    if PY3:
+        __str__ = __unicode__
+
+
+
+class FormatError(Exception):
+    def __init__(self, message, cause=None):
+        super(FormatError, self).__init__(message, cause)
+        self.message = message
+        self.cause = self.__cause__ = cause
+
+    def __str__(self):
+        return self.message.encode("utf-8")
+
+    def __unicode__(self):
+        return self.message
+
+    if PY3:
+        __str__ = __unicode__
+
+
+class ErrorTree(object):
+    """
+    ErrorTrees make it easier to check which validations failed.
+
+    """
+
+    _instance = _unset
+
+    def __init__(self, errors=()):
+        self.errors = {}
+        self._contents = defaultdict(self.__class__)
+
+        for error in errors:
+            container = self
+            for element in error.path:
+                container = container[element]
+            container.errors[error.validator] = error
+
+            self._instance = error.instance
+
+    def __contains__(self, index):
+        """
+        Check whether ``instance[index]`` has any errors.
+
+        """
+
+        return index in self._contents
+
+    def __getitem__(self, index):
+        """
+        Retrieve the child tree one level down at the given ``index``.
+
+        If the index is not in the instance that this tree corresponds to and
+        is not known by this tree, whatever error would be raised by
+        ``instance.__getitem__`` will be propagated (usually this is some
+        subclass of :class:`LookupError`.
+
+        """
+
+        if self._instance is not _unset and index not in self:
+            self._instance[index]
+        return self._contents[index]
+
+    def __setitem__(self, index, value):
+        self._contents[index] = value
+
+    def __iter__(self):
+        """
+        Iterate (non-recursively) over the indices in the instance with errors.
+
+        """
+
+        return iter(self._contents)
+
+    def __len__(self):
+        """
+        Same as :attr:`total_errors`.
+
+        """
+
+        return self.total_errors
+
+    def __repr__(self):
+        return "<%s (%s total errors)>" % (self.__class__.__name__, len(self))
+
+    @property
+    def total_errors(self):
+        """
+        The total number of errors in the entire tree, including children.
+
+        """
+
+        child_errors = sum(len(tree) for _, tree in iteritems(self._contents))
+        return len(self.errors) + child_errors
+
+
+def by_relevance(weak=WEAK_MATCHES, strong=STRONG_MATCHES):
+    def relevance(error):
+        validator = error.validator
+        return -len(error.path), validator not in weak, validator in strong
+    return relevance
+
+
+relevance = by_relevance()
+
+
+def best_match(errors, key=relevance):
+    errors = iter(errors)
+    best = next(errors, None)
+    if best is None:
+        return
+    best = max(itertools.chain([best], errors), key=key)
+
+    while best.context:
+        best = min(best.context, key=key)
+    return best
diff --git a/lib/spack/external/jsonschema/schemas/draft3.json b/lib/spack/external/jsonschema/schemas/draft3.json
new file mode 100644
index 0000000000..5bcefe30d5
--- /dev/null
+++ b/lib/spack/external/jsonschema/schemas/draft3.json
@@ -0,0 +1,201 @@
+{
+    "$schema": "http://json-schema.org/draft-03/schema#",
+    "dependencies": {
+        "exclusiveMaximum": "maximum",
+        "exclusiveMinimum": "minimum"
+    },
+    "id": "http://json-schema.org/draft-03/schema#",
+    "properties": {
+        "$ref": {
+            "format": "uri",
+            "type": "string"
+        },
+        "$schema": {
+            "format": "uri",
+            "type": "string"
+        },
+        "additionalItems": {
+            "default": {},
+            "type": [
+                {
+                    "$ref": "#"
+                },
+                "boolean"
+            ]
+        },
+        "additionalProperties": {
+            "default": {},
+            "type": [
+                {
+                    "$ref": "#"
+                },
+                "boolean"
+            ]
+        },
+        "default": {
+            "type": "any"
+        },
+        "dependencies": {
+            "additionalProperties": {
+                "items": {
+                    "type": "string"
+                },
+                "type": [
+                    "string",
+                    "array",
+                    {
+                        "$ref": "#"
+                    }
+                ]
+            },
+            "default": {},
+            "type": [
+                "string",
+                "array",
+                "object"
+            ]
+        },
+        "description": {
+            "type": "string"
+        },
+        "disallow": {
+            "items": {
+                "type": [
+                    "string",
+                    {
+                        "$ref": "#"
+                    }
+                ]
+            },
+            "type": [
+                "string",
+                "array"
+            ],
+            "uniqueItems": true
+        },
+        "divisibleBy": {
+            "default": 1,
+            "exclusiveMinimum": true,
+            "minimum": 0,
+            "type": "number"
+        },
+        "enum": {
+            "minItems": 1,
+            "type": "array",
+            "uniqueItems": true
+        },
+        "exclusiveMaximum": {
+            "default": false,
+            "type": "boolean"
+        },
+        "exclusiveMinimum": {
+            "default": false,
+            "type": "boolean"
+        },
+        "extends": {
+            "default": {},
+            "items": {
+                "$ref": "#"
+            },
+            "type": [
+                {
+                    "$ref": "#"
+                },
+                "array"
+            ]
+        },
+        "format": {
+            "type": "string"
+        },
+        "id": {
+            "format": "uri",
+            "type": "string"
+        },
+        "items": {
+            "default": {},
+            "items": {
+                "$ref": "#"
+            },
+            "type": [
+                {
+                    "$ref": "#"
+                },
+                "array"
+            ]
+        },
+        "maxDecimal": {
+            "minimum": 0,
+            "type": "number"
+        },
+        "maxItems": {
+            "minimum": 0,
+            "type": "integer"
+        },
+        "maxLength": {
+            "type": "integer"
+        },
+        "maximum": {
+            "type": "number"
+        },
+        "minItems": {
+            "default": 0,
+            "minimum": 0,
+            "type": "integer"
+        },
+        "minLength": {
+            "default": 0,
+            "minimum": 0,
+            "type": "integer"
+        },
+        "minimum": {
+            "type": "number"
+        },
+        "pattern": {
+            "format": "regex",
+            "type": "string"
+        },
+        "patternProperties": {
+            "additionalProperties": {
+                "$ref": "#"
+            },
+            "default": {},
+            "type": "object"
+        },
+        "properties": {
+            "additionalProperties": {
+                "$ref": "#",
+                "type": "object"
+            },
+            "default": {},
+            "type": "object"
+        },
+        "required": {
+            "default": false,
+            "type": "boolean"
+        },
+        "title": {
+            "type": "string"
+        },
+        "type": {
+            "default": "any",
+            "items": {
+                "type": [
+                    "string",
+                    {
+                        "$ref": "#"
+                    }
+                ]
+            },
+            "type": [
+                "string",
+                "array"
+            ],
+            "uniqueItems": true
+        },
+        "uniqueItems": {
+            "default": false,
+            "type": "boolean"
+        }
+    },
+    "type": "object"
+}
diff --git a/lib/spack/external/jsonschema/schemas/draft4.json b/lib/spack/external/jsonschema/schemas/draft4.json
new file mode 100644
index 0000000000..fead5cefab
--- /dev/null
+++ b/lib/spack/external/jsonschema/schemas/draft4.json
@@ -0,0 +1,221 @@
+{
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "default": {},
+    "definitions": {
+        "positiveInteger": {
+            "minimum": 0,
+            "type": "integer"
+        },
+        "positiveIntegerDefault0": {
+            "allOf": [
+                {
+                    "$ref": "#/definitions/positiveInteger"
+                },
+                {
+                    "default": 0
+                }
+            ]
+        },
+        "schemaArray": {
+            "items": {
+                "$ref": "#"
+            },
+            "minItems": 1,
+            "type": "array"
+        },
+        "simpleTypes": {
+            "enum": [
+                "array",
+                "boolean",
+                "integer",
+                "null",
+                "number",
+                "object",
+                "string"
+            ]
+        },
+        "stringArray": {
+            "items": {
+                "type": "string"
+            },
+            "minItems": 1,
+            "type": "array",
+            "uniqueItems": true
+        }
+    },
+    "dependencies": {
+        "exclusiveMaximum": [
+            "maximum"
+        ],
+        "exclusiveMinimum": [
+            "minimum"
+        ]
+    },
+    "description": "Core schema meta-schema",
+    "id": "http://json-schema.org/draft-04/schema#",
+    "properties": {
+        "$schema": {
+            "format": "uri",
+            "type": "string"
+        },
+        "additionalItems": {
+            "anyOf": [
+                {
+                    "type": "boolean"
+                },
+                {
+                    "$ref": "#"
+                }
+            ],
+            "default": {}
+        },
+        "additionalProperties": {
+            "anyOf": [
+                {
+                    "type": "boolean"
+                },
+                {
+                    "$ref": "#"
+                }
+            ],
+            "default": {}
+        },
+        "allOf": {
+            "$ref": "#/definitions/schemaArray"
+        },
+        "anyOf": {
+            "$ref": "#/definitions/schemaArray"
+        },
+        "default": {},
+        "definitions": {
+            "additionalProperties": {
+                "$ref": "#"
+            },
+            "default": {},
+            "type": "object"
+        },
+        "dependencies": {
+            "additionalProperties": {
+                "anyOf": [
+                    {
+                        "$ref": "#"
+                    },
+                    {
+                        "$ref": "#/definitions/stringArray"
+                    }
+                ]
+            },
+            "type": "object"
+        },
+        "description": {
+            "type": "string"
+        },
+        "enum": {
+            "minItems": 1,
+            "type": "array",
+            "uniqueItems": true
+        },
+        "exclusiveMaximum": {
+            "default": false,
+            "type": "boolean"
+        },
+        "exclusiveMinimum": {
+            "default": false,
+            "type": "boolean"
+        },
+        "id": {
+            "format": "uri",
+            "type": "string"
+        },
+        "items": {
+            "anyOf": [
+                {
+                    "$ref": "#"
+                },
+                {
+                    "$ref": "#/definitions/schemaArray"
+                }
+            ],
+            "default": {}
+        },
+        "maxItems": {
+            "$ref": "#/definitions/positiveInteger"
+        },
+        "maxLength": {
+            "$ref": "#/definitions/positiveInteger"
+        },
+        "maxProperties": {
+            "$ref": "#/definitions/positiveInteger"
+        },
+        "maximum": {
+            "type": "number"
+        },
+        "minItems": {
+            "$ref": "#/definitions/positiveIntegerDefault0"
+        },
+        "minLength": {
+            "$ref": "#/definitions/positiveIntegerDefault0"
+        },
+        "minProperties": {
+            "$ref": "#/definitions/positiveIntegerDefault0"
+        },
+        "minimum": {
+            "type": "number"
+        },
+        "multipleOf": {
+            "exclusiveMinimum": true,
+            "minimum": 0,
+            "type": "number"
+        },
+        "not": {
+            "$ref": "#"
+        },
+        "oneOf": {
+            "$ref": "#/definitions/schemaArray"
+        },
+        "pattern": {
+            "format": "regex",
+            "type": "string"
+        },
+        "patternProperties": {
+            "additionalProperties": {
+                "$ref": "#"
+            },
+            "default": {},
+            "type": "object"
+        },
+        "properties": {
+            "additionalProperties": {
+                "$ref": "#"
+            },
+            "default": {},
+            "type": "object"
+        },
+        "required": {
+            "$ref": "#/definitions/stringArray"
+        },
+        "title": {
+            "type": "string"
+        },
+        "type": {
+            "anyOf": [
+                {
+                    "$ref": "#/definitions/simpleTypes"
+                },
+                {
+                    "items": {
+                        "$ref": "#/definitions/simpleTypes"
+                    },
+                    "minItems": 1,
+                    "type": "array",
+                    "uniqueItems": true
+                }
+            ]
+        },
+        "uniqueItems": {
+            "default": false,
+            "type": "boolean"
+        }
+    },
+    "type": "object"
+}
diff --git a/lib/spack/external/jsonschema/tests/__init__.py b/lib/spack/external/jsonschema/tests/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/__init__.py
diff --git a/lib/spack/external/jsonschema/tests/compat.py b/lib/spack/external/jsonschema/tests/compat.py
new file mode 100644
index 0000000000..b37483f5dd
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/compat.py
@@ -0,0 +1,15 @@
+import sys
+
+
+if sys.version_info[:2] < (2, 7):  # pragma: no cover
+    import unittest2 as unittest
+else:
+    import unittest
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+
+# flake8: noqa
diff --git a/lib/spack/external/jsonschema/tests/test_cli.py b/lib/spack/external/jsonschema/tests/test_cli.py
new file mode 100644
index 0000000000..f625ca989d
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/test_cli.py
@@ -0,0 +1,110 @@
+from jsonschema import Draft4Validator, ValidationError, cli
+from jsonschema.compat import StringIO
+from jsonschema.tests.compat import mock, unittest
+
+
+def fake_validator(*errors):
+    errors = list(reversed(errors))
+
+    class FakeValidator(object):
+        def __init__(self, *args, **kwargs):
+            pass
+
+        def iter_errors(self, instance):
+            if errors:
+                return errors.pop()
+            return []
+    return FakeValidator
+
+
+class TestParser(unittest.TestCase):
+    FakeValidator = fake_validator()
+
+    def setUp(self):
+        mock_open = mock.mock_open()
+        patch_open = mock.patch.object(cli, "open", mock_open, create=True)
+        patch_open.start()
+        self.addCleanup(patch_open.stop)
+
+        mock_json_load = mock.Mock()
+        mock_json_load.return_value = {}
+        patch_json_load = mock.patch("json.load")
+        patch_json_load.start()
+        self.addCleanup(patch_json_load.stop)
+
+    def test_find_validator_by_fully_qualified_object_name(self):
+        arguments = cli.parse_args(
+            [
+                "--validator",
+                "jsonschema.tests.test_cli.TestParser.FakeValidator",
+                "--instance", "foo.json",
+                "schema.json",
+            ]
+        )
+        self.assertIs(arguments["validator"], self.FakeValidator)
+
+    def test_find_validator_in_jsonschema(self):
+        arguments = cli.parse_args(
+            [
+                "--validator", "Draft4Validator",
+                "--instance", "foo.json",
+                "schema.json",
+            ]
+        )
+        self.assertIs(arguments["validator"], Draft4Validator)
+
+
+class TestCLI(unittest.TestCase):
+    def test_successful_validation(self):
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator": fake_validator(),
+                "schema": {},
+                "instances": [1],
+                "error_format": "{error.message}",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertFalse(stderr.getvalue())
+        self.assertEqual(exit_code, 0)
+
+    def test_unsuccessful_validation(self):
+        error = ValidationError("I am an error!", instance=1)
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator": fake_validator([error]),
+                "schema": {},
+                "instances": [1],
+                "error_format": "{error.instance} - {error.message}",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertEqual(stderr.getvalue(), "1 - I am an error!")
+        self.assertEqual(exit_code, 1)
+
+    def test_unsuccessful_validation_multiple_instances(self):
+        first_errors = [
+            ValidationError("9", instance=1),
+            ValidationError("8", instance=1),
+        ]
+        second_errors = [ValidationError("7", instance=2)]
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator": fake_validator(first_errors, second_errors),
+                "schema": {},
+                "instances": [1, 2],
+                "error_format": "{error.instance} - {error.message}\t",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertEqual(stderr.getvalue(), "1 - 9\t1 - 8\t2 - 7\t")
+        self.assertEqual(exit_code, 1)
diff --git a/lib/spack/external/jsonschema/tests/test_exceptions.py b/lib/spack/external/jsonschema/tests/test_exceptions.py
new file mode 100644
index 0000000000..9e5793c628
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/test_exceptions.py
@@ -0,0 +1,382 @@
+import textwrap
+
+from jsonschema import Draft4Validator, exceptions
+from jsonschema.compat import PY3
+from jsonschema.tests.compat import mock, unittest
+
+
+class TestBestMatch(unittest.TestCase):
+    def best_match(self, errors):
+        errors = list(errors)
+        best = exceptions.best_match(errors)
+        reversed_best = exceptions.best_match(reversed(errors))
+        self.assertEqual(
+            best,
+            reversed_best,
+            msg="Didn't return a consistent best match!\n"
+                "Got: {0}\n\nThen: {1}".format(best, reversed_best),
+        )
+        return best
+
+    def test_shallower_errors_are_better_matches(self):
+        validator = Draft4Validator(
+            {
+                "properties" : {
+                    "foo" : {
+                        "minProperties" : 2,
+                        "properties" : {"bar" : {"type" : "object"}},
+                    }
+                }
+            }
+        )
+        best = self.best_match(validator.iter_errors({"foo" : {"bar" : []}}))
+        self.assertEqual(best.validator, "minProperties")
+
+    def test_oneOf_and_anyOf_are_weak_matches(self):
+        """
+        A property you *must* match is probably better than one you have to
+        match a part of.
+
+        """
+
+        validator = Draft4Validator(
+            {
+                "minProperties" : 2,
+                "anyOf" : [{"type" : "string"}, {"type" : "number"}],
+                "oneOf" : [{"type" : "string"}, {"type" : "number"}],
+            }
+        )
+        best = self.best_match(validator.iter_errors({}))
+        self.assertEqual(best.validator, "minProperties")
+
+    def test_if_the_most_relevant_error_is_anyOf_it_is_traversed(self):
+        """
+        If the most relevant error is an anyOf, then we traverse its context
+        and select the otherwise *least* relevant error, since in this case
+        that means the most specific, deep, error inside the instance.
+
+        I.e. since only one of the schemas must match, we look for the most
+        relevant one.
+
+        """
+
+        validator = Draft4Validator(
+            {
+                "properties" : {
+                    "foo" : {
+                        "anyOf" : [
+                            {"type" : "string"},
+                            {"properties" : {"bar" : {"type" : "array"}}},
+                        ],
+                    },
+                },
+            },
+        )
+        best = self.best_match(validator.iter_errors({"foo" : {"bar" : 12}}))
+        self.assertEqual(best.validator_value, "array")
+
+    def test_if_the_most_relevant_error_is_oneOf_it_is_traversed(self):
+        """
+        If the most relevant error is an oneOf, then we traverse its context
+        and select the otherwise *least* relevant error, since in this case
+        that means the most specific, deep, error inside the instance.
+
+        I.e. since only one of the schemas must match, we look for the most
+        relevant one.
+
+        """
+
+        validator = Draft4Validator(
+            {
+                "properties" : {
+                    "foo" : {
+                        "oneOf" : [
+                            {"type" : "string"},
+                            {"properties" : {"bar" : {"type" : "array"}}},
+                        ],
+                    },
+                },
+            },
+        )
+        best = self.best_match(validator.iter_errors({"foo" : {"bar" : 12}}))
+        self.assertEqual(best.validator_value, "array")
+
+    def test_if_the_most_relevant_error_is_allOf_it_is_traversed(self):
+        """
+        Now, if the error is allOf, we traverse but select the *most* relevant
+        error from the context, because all schemas here must match anyways.
+
+        """
+
+        validator = Draft4Validator(
+            {
+                "properties" : {
+                    "foo" : {
+                        "allOf" : [
+                            {"type" : "string"},
+                            {"properties" : {"bar" : {"type" : "array"}}},
+                        ],
+                    },
+                },
+            },
+        )
+        best = self.best_match(validator.iter_errors({"foo" : {"bar" : 12}}))
+        self.assertEqual(best.validator_value, "string")
+
+    def test_nested_context_for_oneOf(self):
+        validator = Draft4Validator(
+            {
+                "properties" : {
+                    "foo" : {
+                        "oneOf" : [
+                            {"type" : "string"},
+                            {
+                                "oneOf" : [
+                                    {"type" : "string"},
+                                    {
+                                        "properties" : {
+                                            "bar" : {"type" : "array"}
+                                        },
+                                    },
+                                ],
+                            },
+                        ],
+                    },
+                },
+            },
+        )
+        best = self.best_match(validator.iter_errors({"foo" : {"bar" : 12}}))
+        self.assertEqual(best.validator_value, "array")
+
+    def test_one_error(self):
+        validator = Draft4Validator({"minProperties" : 2})
+        error, = validator.iter_errors({})
+        self.assertEqual(
+            exceptions.best_match(validator.iter_errors({})).validator,
+            "minProperties",
+        )
+
+    def test_no_errors(self):
+        validator = Draft4Validator({})
+        self.assertIsNone(exceptions.best_match(validator.iter_errors({})))
+
+
+class TestByRelevance(unittest.TestCase):
+    def test_short_paths_are_better_matches(self):
+        shallow = exceptions.ValidationError("Oh no!", path=["baz"])
+        deep = exceptions.ValidationError("Oh yes!", path=["foo", "bar"])
+        match = max([shallow, deep], key=exceptions.relevance)
+        self.assertIs(match, shallow)
+
+        match = max([deep, shallow], key=exceptions.relevance)
+        self.assertIs(match, shallow)
+
+    def test_global_errors_are_even_better_matches(self):
+        shallow = exceptions.ValidationError("Oh no!", path=[])
+        deep = exceptions.ValidationError("Oh yes!", path=["foo"])
+
+        errors = sorted([shallow, deep], key=exceptions.relevance)
+        self.assertEqual(
+            [list(error.path) for error in errors],
+            [["foo"], []],
+        )
+
+        errors = sorted([deep, shallow], key=exceptions.relevance)
+        self.assertEqual(
+            [list(error.path) for error in errors],
+            [["foo"], []],
+        )
+
+    def test_weak_validators_are_lower_priority(self):
+        weak = exceptions.ValidationError("Oh no!", path=[], validator="a")
+        normal = exceptions.ValidationError("Oh yes!", path=[], validator="b")
+
+        best_match = exceptions.by_relevance(weak="a")
+
+        match = max([weak, normal], key=best_match)
+        self.assertIs(match, normal)
+
+        match = max([normal, weak], key=best_match)
+        self.assertIs(match, normal)
+
+    def test_strong_validators_are_higher_priority(self):
+        weak = exceptions.ValidationError("Oh no!", path=[], validator="a")
+        normal = exceptions.ValidationError("Oh yes!", path=[], validator="b")
+        strong = exceptions.ValidationError("Oh fine!", path=[], validator="c")
+
+        best_match = exceptions.by_relevance(weak="a", strong="c")
+
+        match = max([weak, normal, strong], key=best_match)
+        self.assertIs(match, strong)
+
+        match = max([strong, normal, weak], key=best_match)
+        self.assertIs(match, strong)
+
+
+class TestErrorTree(unittest.TestCase):
+    def test_it_knows_how_many_total_errors_it_contains(self):
+        errors = [mock.MagicMock() for _ in range(8)]
+        tree = exceptions.ErrorTree(errors)
+        self.assertEqual(tree.total_errors, 8)
+
+    def test_it_contains_an_item_if_the_item_had_an_error(self):
+        errors = [exceptions.ValidationError("a message", path=["bar"])]
+        tree = exceptions.ErrorTree(errors)
+        self.assertIn("bar", tree)
+
+    def test_it_does_not_contain_an_item_if_the_item_had_no_error(self):
+        errors = [exceptions.ValidationError("a message", path=["bar"])]
+        tree = exceptions.ErrorTree(errors)
+        self.assertNotIn("foo", tree)
+
+    def test_validators_that_failed_appear_in_errors_dict(self):
+        error = exceptions.ValidationError("a message", validator="foo")
+        tree = exceptions.ErrorTree([error])
+        self.assertEqual(tree.errors, {"foo" : error})
+
+    def test_it_creates_a_child_tree_for_each_nested_path(self):
+        errors = [
+            exceptions.ValidationError("a bar message", path=["bar"]),
+            exceptions.ValidationError("a bar -> 0 message", path=["bar", 0]),
+        ]
+        tree = exceptions.ErrorTree(errors)
+        self.assertIn(0, tree["bar"])
+        self.assertNotIn(1, tree["bar"])
+
+    def test_children_have_their_errors_dicts_built(self):
+        e1, e2 = (
+            exceptions.ValidationError("1", validator="foo", path=["bar", 0]),
+            exceptions.ValidationError("2", validator="quux", path=["bar", 0]),
+        )
+        tree = exceptions.ErrorTree([e1, e2])
+        self.assertEqual(tree["bar"][0].errors, {"foo" : e1, "quux" : e2})
+
+    def test_it_does_not_contain_subtrees_that_are_not_in_the_instance(self):
+        error = exceptions.ValidationError("123", validator="foo", instance=[])
+        tree = exceptions.ErrorTree([error])
+
+        with self.assertRaises(IndexError):
+            tree[0]
+
+    def test_if_its_in_the_tree_anyhow_it_does_not_raise_an_error(self):
+        """
+        If a validator is dumb (like :validator:`required` in draft 3) and
+        refers to a path that isn't in the instance, the tree still properly
+        returns a subtree for that path.
+
+        """
+
+        error = exceptions.ValidationError(
+            "a message", validator="foo", instance={}, path=["foo"],
+        )
+        tree = exceptions.ErrorTree([error])
+        self.assertIsInstance(tree["foo"], exceptions.ErrorTree)
+
+
+class TestErrorReprStr(unittest.TestCase):
+    def make_error(self, **kwargs):
+        defaults = dict(
+            message=u"hello",
+            validator=u"type",
+            validator_value=u"string",
+            instance=5,
+            schema={u"type": u"string"},
+        )
+        defaults.update(kwargs)
+        return exceptions.ValidationError(**defaults)
+
+    def assertShows(self, expected, **kwargs):
+        if PY3:
+            expected = expected.replace("u'", "'")
+        expected = textwrap.dedent(expected).rstrip("\n")
+
+        error = self.make_error(**kwargs)
+        message_line, _, rest = str(error).partition("\n")
+        self.assertEqual(message_line, error.message)
+        self.assertEqual(rest, expected)
+
+    def test_repr(self):
+        self.assertEqual(
+            repr(exceptions.ValidationError(message="Hello!")),
+            "<ValidationError: %r>" % "Hello!",
+        )
+
+    def test_unset_error(self):
+        error = exceptions.ValidationError("message")
+        self.assertEqual(str(error), "message")
+
+        kwargs = {
+            "validator": "type",
+            "validator_value": "string",
+            "instance": 5,
+            "schema": {"type": "string"}
+        }
+        # Just the message should show if any of the attributes are unset
+        for attr in kwargs:
+            k = dict(kwargs)
+            del k[attr]
+            error = exceptions.ValidationError("message", **k)
+            self.assertEqual(str(error), "message")
+
+    def test_empty_paths(self):
+        self.assertShows(
+            """
+            Failed validating u'type' in schema:
+                {u'type': u'string'}
+
+            On instance:
+                5
+            """,
+            path=[],
+            schema_path=[],
+        )
+
+    def test_one_item_paths(self):
+        self.assertShows(
+            """
+            Failed validating u'type' in schema:
+                {u'type': u'string'}
+
+            On instance[0]:
+                5
+            """,
+            path=[0],
+            schema_path=["items"],
+        )
+
+    def test_multiple_item_paths(self):
+        self.assertShows(
+            """
+            Failed validating u'type' in schema[u'items'][0]:
+                {u'type': u'string'}
+
+            On instance[0][u'a']:
+                5
+            """,
+            path=[0, u"a"],
+            schema_path=[u"items", 0, 1],
+        )
+
+    def test_uses_pprint(self):
+        with mock.patch("pprint.pformat") as pformat:
+            str(self.make_error())
+            self.assertEqual(pformat.call_count, 2)  # schema + instance
+
+    def test_str_works_with_instances_having_overriden_eq_operator(self):
+        """
+        Check for https://github.com/Julian/jsonschema/issues/164 which
+        rendered exceptions unusable when a `ValidationError` involved
+        instances with an `__eq__` method that returned truthy values.
+
+        """
+
+        instance = mock.MagicMock()
+        error = exceptions.ValidationError(
+            "a message",
+            validator="foo",
+            instance=instance,
+            validator_value="some",
+            schema="schema",
+        )
+        str(error)
+        self.assertFalse(instance.__eq__.called)
diff --git a/lib/spack/external/jsonschema/tests/test_format.py b/lib/spack/external/jsonschema/tests/test_format.py
new file mode 100644
index 0000000000..8392ca1de3
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/test_format.py
@@ -0,0 +1,63 @@
+"""
+Tests for the parts of jsonschema related to the :validator:`format` property.
+
+"""
+
+from jsonschema.tests.compat import mock, unittest
+
+from jsonschema import FormatError, ValidationError, FormatChecker
+from jsonschema.validators import Draft4Validator
+
+
+class TestFormatChecker(unittest.TestCase):
+    def setUp(self):
+        self.fn = mock.Mock()
+
+    def test_it_can_validate_no_formats(self):
+        checker = FormatChecker(formats=())
+        self.assertFalse(checker.checkers)
+
+    def test_it_raises_a_key_error_for_unknown_formats(self):
+        with self.assertRaises(KeyError):
+            FormatChecker(formats=["o noes"])
+
+    def test_it_can_register_cls_checkers(self):
+        with mock.patch.dict(FormatChecker.checkers, clear=True):
+            FormatChecker.cls_checks("new")(self.fn)
+            self.assertEqual(FormatChecker.checkers, {"new" : (self.fn, ())})
+
+    def test_it_can_register_checkers(self):
+        checker = FormatChecker()
+        checker.checks("new")(self.fn)
+        self.assertEqual(
+            checker.checkers,
+            dict(FormatChecker.checkers, new=(self.fn, ()))
+        )
+
+    def test_it_catches_registered_errors(self):
+        checker = FormatChecker()
+        cause = self.fn.side_effect = ValueError()
+
+        checker.checks("foo", raises=ValueError)(self.fn)
+
+        with self.assertRaises(FormatError) as cm:
+            checker.check("bar", "foo")
+
+        self.assertIs(cm.exception.cause, cause)
+        self.assertIs(cm.exception.__cause__, cause)
+
+        # Unregistered errors should not be caught
+        self.fn.side_effect = AttributeError
+        with self.assertRaises(AttributeError):
+            checker.check("bar", "foo")
+
+    def test_format_error_causes_become_validation_error_causes(self):
+        checker = FormatChecker()
+        checker.checks("foo", raises=ValueError)(self.fn)
+        cause = self.fn.side_effect = ValueError()
+        validator = Draft4Validator({"format" : "foo"}, format_checker=checker)
+
+        with self.assertRaises(ValidationError) as cm:
+            validator.validate("bar")
+
+        self.assertIs(cm.exception.__cause__, cause)
diff --git a/lib/spack/external/jsonschema/tests/test_jsonschema_test_suite.py b/lib/spack/external/jsonschema/tests/test_jsonschema_test_suite.py
new file mode 100644
index 0000000000..75c6857bc0
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/test_jsonschema_test_suite.py
@@ -0,0 +1,290 @@
+"""
+Test runner for the JSON Schema official test suite
+
+Tests comprehensive correctness of each draft's validator.
+
+See https://github.com/json-schema/JSON-Schema-Test-Suite for details.
+
+"""
+
+from contextlib import closing
+from decimal import Decimal
+import glob
+import json
+import io
+import itertools
+import os
+import re
+import subprocess
+import sys
+
+try:
+    from sys import pypy_version_info
+except ImportError:
+    pypy_version_info = None
+
+from jsonschema import (
+    FormatError, SchemaError, ValidationError, Draft3Validator,
+    Draft4Validator, FormatChecker, draft3_format_checker,
+    draft4_format_checker, validate,
+)
+from jsonschema.compat import PY3
+from jsonschema.tests.compat import mock, unittest
+import jsonschema
+
+
+REPO_ROOT = os.path.join(os.path.dirname(jsonschema.__file__), os.path.pardir)
+SUITE = os.getenv("JSON_SCHEMA_TEST_SUITE", os.path.join(REPO_ROOT, "json"))
+
+if not os.path.isdir(SUITE):
+    raise ValueError(
+        "Can't find the JSON-Schema-Test-Suite directory. Set the "
+        "'JSON_SCHEMA_TEST_SUITE' environment variable or run the tests from "
+        "alongside a checkout of the suite."
+    )
+
+TESTS_DIR = os.path.join(SUITE, "tests")
+JSONSCHEMA_SUITE = os.path.join(SUITE, "bin", "jsonschema_suite")
+
+remotes_stdout = subprocess.Popen(
+    ["python", JSONSCHEMA_SUITE, "remotes"], stdout=subprocess.PIPE,
+).stdout
+
+with closing(remotes_stdout):
+    if PY3:
+        remotes_stdout = io.TextIOWrapper(remotes_stdout)
+    REMOTES = json.load(remotes_stdout)
+
+
+def make_case(schema, data, valid, name):
+    if valid:
+        def test_case(self):
+            kwargs = getattr(self, "validator_kwargs", {})
+            validate(data, schema, cls=self.validator_class, **kwargs)
+    else:
+        def test_case(self):
+            kwargs = getattr(self, "validator_kwargs", {})
+            with self.assertRaises(ValidationError):
+                validate(data, schema, cls=self.validator_class, **kwargs)
+
+    if not PY3:
+        name = name.encode("utf-8")
+    test_case.__name__ = name
+
+    return test_case
+
+
+def maybe_skip(skip, test_case, case, test):
+    if skip is not None:
+        reason = skip(case, test)
+        if reason is not None:
+            test_case = unittest.skip(reason)(test_case)
+    return test_case
+
+
+def load_json_cases(tests_glob, ignore_glob="", basedir=TESTS_DIR, skip=None):
+    if ignore_glob:
+        ignore_glob = os.path.join(basedir, ignore_glob)
+
+    def add_test_methods(test_class):
+        ignored = set(glob.iglob(ignore_glob))
+
+        for filename in glob.iglob(os.path.join(basedir, tests_glob)):
+            if filename in ignored:
+                continue
+
+            validating, _ = os.path.splitext(os.path.basename(filename))
+            id = itertools.count(1)
+
+            with open(filename) as test_file:
+                for case in json.load(test_file):
+                    for test in case["tests"]:
+                        name = "test_%s_%s_%s" % (
+                            validating,
+                            next(id),
+                            re.sub(r"[\W ]+", "_", test["description"]),
+                        )
+                        assert not hasattr(test_class, name), name
+
+                        test_case = make_case(
+                            data=test["data"],
+                            schema=case["schema"],
+                            valid=test["valid"],
+                            name=name,
+                        )
+                        test_case = maybe_skip(skip, test_case, case, test)
+                        setattr(test_class, name, test_case)
+
+        return test_class
+    return add_test_methods
+
+
+class TypesMixin(object):
+    @unittest.skipIf(PY3, "In Python 3 json.load always produces unicode")
+    def test_string_a_bytestring_is_a_string(self):
+        self.validator_class({"type" : "string"}).validate(b"foo")
+
+
+class DecimalMixin(object):
+    def test_it_can_validate_with_decimals(self):
+        schema = {"type" : "number"}
+        validator = self.validator_class(
+            schema, types={"number" : (int, float, Decimal)}
+        )
+
+        for valid in [1, 1.1, Decimal(1) / Decimal(8)]:
+            validator.validate(valid)
+
+        for invalid in ["foo", {}, [], True, None]:
+            with self.assertRaises(ValidationError):
+                validator.validate(invalid)
+
+
+def missing_format(checker):
+    def missing_format(case, test):
+        format = case["schema"].get("format")
+        if format not in checker.checkers:
+            return "Format checker {0!r} not found.".format(format)
+        elif (
+            format == "date-time" and
+            pypy_version_info is not None and
+            pypy_version_info[:2] <= (1, 9)
+        ):
+            # datetime.datetime is overzealous about typechecking in <=1.9
+            return "datetime.datetime is broken on this version of PyPy."
+    return missing_format
+
+
+class FormatMixin(object):
+    def test_it_returns_true_for_formats_it_does_not_know_about(self):
+        validator = self.validator_class(
+            {"format" : "carrot"}, format_checker=FormatChecker(),
+        )
+        validator.validate("bugs")
+
+    def test_it_does_not_validate_formats_by_default(self):
+        validator = self.validator_class({})
+        self.assertIsNone(validator.format_checker)
+
+    def test_it_validates_formats_if_a_checker_is_provided(self):
+        checker = mock.Mock(spec=FormatChecker)
+        validator = self.validator_class(
+            {"format" : "foo"}, format_checker=checker,
+        )
+
+        validator.validate("bar")
+
+        checker.check.assert_called_once_with("bar", "foo")
+
+        cause = ValueError()
+        checker.check.side_effect = FormatError('aoeu', cause=cause)
+
+        with self.assertRaises(ValidationError) as cm:
+            validator.validate("bar")
+        # Make sure original cause is attached
+        self.assertIs(cm.exception.cause, cause)
+
+    def test_it_validates_formats_of_any_type(self):
+        checker = mock.Mock(spec=FormatChecker)
+        validator = self.validator_class(
+            {"format" : "foo"}, format_checker=checker,
+        )
+
+        validator.validate([1, 2, 3])
+
+        checker.check.assert_called_once_with([1, 2, 3], "foo")
+
+        cause = ValueError()
+        checker.check.side_effect = FormatError('aoeu', cause=cause)
+
+        with self.assertRaises(ValidationError) as cm:
+            validator.validate([1, 2, 3])
+        # Make sure original cause is attached
+        self.assertIs(cm.exception.cause, cause)
+
+
+if sys.maxunicode == 2 ** 16 - 1:          # This is a narrow build.
+    def narrow_unicode_build(case, test):
+        if "supplementary Unicode" in test["description"]:
+            return "Not running surrogate Unicode case, this Python is narrow."
+else:
+    def narrow_unicode_build(case, test):  # This isn't, skip nothing.
+        return
+
+
+@load_json_cases(
+    "draft3/*.json",
+    skip=narrow_unicode_build,
+    ignore_glob="draft3/refRemote.json",
+)
+@load_json_cases(
+    "draft3/optional/format.json", skip=missing_format(draft3_format_checker)
+)
+@load_json_cases("draft3/optional/bignum.json")
+@load_json_cases("draft3/optional/zeroTerminatedFloats.json")
+class TestDraft3(unittest.TestCase, TypesMixin, DecimalMixin, FormatMixin):
+    validator_class = Draft3Validator
+    validator_kwargs = {"format_checker" : draft3_format_checker}
+
+    def test_any_type_is_valid_for_type_any(self):
+        validator = self.validator_class({"type" : "any"})
+        validator.validate(mock.Mock())
+
+    # TODO: we're in need of more meta schema tests
+    def test_invalid_properties(self):
+        with self.assertRaises(SchemaError):
+            validate({}, {"properties": {"test": True}},
+                     cls=self.validator_class)
+
+    def test_minItems_invalid_string(self):
+        with self.assertRaises(SchemaError):
+            # needs to be an integer
+            validate([1], {"minItems" : "1"}, cls=self.validator_class)
+
+
+@load_json_cases(
+    "draft4/*.json",
+    skip=narrow_unicode_build,
+    ignore_glob="draft4/refRemote.json",
+)
+@load_json_cases(
+    "draft4/optional/format.json", skip=missing_format(draft4_format_checker)
+)
+@load_json_cases("draft4/optional/bignum.json")
+@load_json_cases("draft4/optional/zeroTerminatedFloats.json")
+class TestDraft4(unittest.TestCase, TypesMixin, DecimalMixin, FormatMixin):
+    validator_class = Draft4Validator
+    validator_kwargs = {"format_checker" : draft4_format_checker}
+
+    # TODO: we're in need of more meta schema tests
+    def test_invalid_properties(self):
+        with self.assertRaises(SchemaError):
+            validate({}, {"properties": {"test": True}},
+                     cls=self.validator_class)
+
+    def test_minItems_invalid_string(self):
+        with self.assertRaises(SchemaError):
+            # needs to be an integer
+            validate([1], {"minItems" : "1"}, cls=self.validator_class)
+
+
+class RemoteRefResolutionMixin(object):
+    def setUp(self):
+        patch = mock.patch("jsonschema.validators.requests")
+        requests = patch.start()
+        requests.get.side_effect = self.resolve
+        self.addCleanup(patch.stop)
+
+    def resolve(self, reference):
+        _, _, reference = reference.partition("http://localhost:1234/")
+        return mock.Mock(**{"json.return_value" : REMOTES.get(reference)})
+
+
+@load_json_cases("draft3/refRemote.json")
+class Draft3RemoteResolution(RemoteRefResolutionMixin, unittest.TestCase):
+    validator_class = Draft3Validator
+
+
+@load_json_cases("draft4/refRemote.json")
+class Draft4RemoteResolution(RemoteRefResolutionMixin, unittest.TestCase):
+    validator_class = Draft4Validator
diff --git a/lib/spack/external/jsonschema/tests/test_validators.py b/lib/spack/external/jsonschema/tests/test_validators.py
new file mode 100644
index 0000000000..f8692388ea
--- /dev/null
+++ b/lib/spack/external/jsonschema/tests/test_validators.py
@@ -0,0 +1,786 @@
+from collections import deque
+from contextlib import contextmanager
+import json
+
+from jsonschema import FormatChecker, ValidationError
+from jsonschema.tests.compat import mock, unittest
+from jsonschema.validators import (
+    RefResolutionError, UnknownType, Draft3Validator,
+    Draft4Validator, RefResolver, create, extend, validator_for, validate,
+)
+
+
+class TestCreateAndExtend(unittest.TestCase):
+    def setUp(self):
+        self.meta_schema = {u"properties" : {u"smelly" : {}}}
+        self.smelly = mock.MagicMock()
+        self.validators = {u"smelly" : self.smelly}
+        self.types = {u"dict" : dict}
+        self.Validator = create(
+            meta_schema=self.meta_schema,
+            validators=self.validators,
+            default_types=self.types,
+        )
+
+        self.validator_value = 12
+        self.schema = {u"smelly" : self.validator_value}
+        self.validator = self.Validator(self.schema)
+
+    def test_attrs(self):
+        self.assertEqual(self.Validator.VALIDATORS, self.validators)
+        self.assertEqual(self.Validator.META_SCHEMA, self.meta_schema)
+        self.assertEqual(self.Validator.DEFAULT_TYPES, self.types)
+
+    def test_init(self):
+        self.assertEqual(self.validator.schema, self.schema)
+
+    def test_iter_errors(self):
+        instance = "hello"
+
+        self.smelly.return_value = []
+        self.assertEqual(list(self.validator.iter_errors(instance)), [])
+
+        error = mock.Mock()
+        self.smelly.return_value = [error]
+        self.assertEqual(list(self.validator.iter_errors(instance)), [error])
+
+        self.smelly.assert_called_with(
+            self.validator, self.validator_value, instance, self.schema,
+        )
+
+    def test_if_a_version_is_provided_it_is_registered(self):
+        with mock.patch("jsonschema.validators.validates") as validates:
+            validates.side_effect = lambda version : lambda cls : cls
+            Validator = create(meta_schema={u"id" : ""}, version="my version")
+        validates.assert_called_once_with("my version")
+        self.assertEqual(Validator.__name__, "MyVersionValidator")
+
+    def test_if_a_version_is_not_provided_it_is_not_registered(self):
+        with mock.patch("jsonschema.validators.validates") as validates:
+            create(meta_schema={u"id" : "id"})
+        self.assertFalse(validates.called)
+
+    def test_extend(self):
+        validators = dict(self.Validator.VALIDATORS)
+        new = mock.Mock()
+
+        Extended = extend(self.Validator, validators={u"a new one" : new})
+
+        validators.update([(u"a new one", new)])
+        self.assertEqual(Extended.VALIDATORS, validators)
+        self.assertNotIn(u"a new one", self.Validator.VALIDATORS)
+
+        self.assertEqual(Extended.META_SCHEMA, self.Validator.META_SCHEMA)
+        self.assertEqual(Extended.DEFAULT_TYPES, self.Validator.DEFAULT_TYPES)
+
+
+class TestIterErrors(unittest.TestCase):
+    def setUp(self):
+        self.validator = Draft3Validator({})
+
+    def test_iter_errors(self):
+        instance = [1, 2]
+        schema = {
+            u"disallow" : u"array",
+            u"enum" : [["a", "b", "c"], ["d", "e", "f"]],
+            u"minItems" : 3
+        }
+
+        got = (e.message for e in self.validator.iter_errors(instance, schema))
+        expected = [
+            "%r is disallowed for [1, 2]" % (schema["disallow"],),
+            "[1, 2] is too short",
+            "[1, 2] is not one of %r" % (schema["enum"],),
+        ]
+        self.assertEqual(sorted(got), sorted(expected))
+
+    def test_iter_errors_multiple_failures_one_validator(self):
+        instance = {"foo" : 2, "bar" : [1], "baz" : 15, "quux" : "spam"}
+        schema = {
+            u"properties" : {
+                "foo" : {u"type" : "string"},
+                "bar" : {u"minItems" : 2},
+                "baz" : {u"maximum" : 10, u"enum" : [2, 4, 6, 8]},
+            }
+        }
+
+        errors = list(self.validator.iter_errors(instance, schema))
+        self.assertEqual(len(errors), 4)
+
+
+class TestValidationErrorMessages(unittest.TestCase):
+    def message_for(self, instance, schema, *args, **kwargs):
+        kwargs.setdefault("cls", Draft3Validator)
+        with self.assertRaises(ValidationError) as e:
+            validate(instance, schema, *args, **kwargs)
+        return e.exception.message
+
+    def test_single_type_failure(self):
+        message = self.message_for(instance=1, schema={u"type" : u"string"})
+        self.assertEqual(message, "1 is not of type %r" % u"string")
+
+    def test_single_type_list_failure(self):
+        message = self.message_for(instance=1, schema={u"type" : [u"string"]})
+        self.assertEqual(message, "1 is not of type %r" % u"string")
+
+    def test_multiple_type_failure(self):
+        types = u"string", u"object"
+        message = self.message_for(instance=1, schema={u"type" : list(types)})
+        self.assertEqual(message, "1 is not of type %r, %r" % types)
+
+    def test_object_without_title_type_failure(self):
+        type = {u"type" : [{u"minimum" : 3}]}
+        message = self.message_for(instance=1, schema={u"type" : [type]})
+        self.assertEqual(message, "1 is not of type %r" % (type,))
+
+    def test_object_with_name_type_failure(self):
+        name = "Foo"
+        schema = {u"type" : [{u"name" : name, u"minimum" : 3}]}
+        message = self.message_for(instance=1, schema=schema)
+        self.assertEqual(message, "1 is not of type %r" % (name,))
+
+    def test_minimum(self):
+        message = self.message_for(instance=1, schema={"minimum" : 2})
+        self.assertEqual(message, "1 is less than the minimum of 2")
+
+    def test_maximum(self):
+        message = self.message_for(instance=1, schema={"maximum" : 0})
+        self.assertEqual(message, "1 is greater than the maximum of 0")
+
+    def test_dependencies_failure_has_single_element_not_list(self):
+        depend, on = "bar", "foo"
+        schema = {u"dependencies" : {depend : on}}
+        message = self.message_for({"bar" : 2}, schema)
+        self.assertEqual(message, "%r is a dependency of %r" % (on, depend))
+
+    def test_additionalItems_single_failure(self):
+        message = self.message_for(
+            [2], {u"items" : [], u"additionalItems" : False},
+        )
+        self.assertIn("(2 was unexpected)", message)
+
+    def test_additionalItems_multiple_failures(self):
+        message = self.message_for(
+            [1, 2, 3], {u"items" : [], u"additionalItems" : False}
+        )
+        self.assertIn("(1, 2, 3 were unexpected)", message)
+
+    def test_additionalProperties_single_failure(self):
+        additional = "foo"
+        schema = {u"additionalProperties" : False}
+        message = self.message_for({additional : 2}, schema)
+        self.assertIn("(%r was unexpected)" % (additional,), message)
+
+    def test_additionalProperties_multiple_failures(self):
+        schema = {u"additionalProperties" : False}
+        message = self.message_for(dict.fromkeys(["foo", "bar"]), schema)
+
+        self.assertIn(repr("foo"), message)
+        self.assertIn(repr("bar"), message)
+        self.assertIn("were unexpected)", message)
+
+    def test_invalid_format_default_message(self):
+        checker = FormatChecker(formats=())
+        check_fn = mock.Mock(return_value=False)
+        checker.checks(u"thing")(check_fn)
+
+        schema = {u"format" : u"thing"}
+        message = self.message_for("bla", schema, format_checker=checker)
+
+        self.assertIn(repr("bla"), message)
+        self.assertIn(repr("thing"), message)
+        self.assertIn("is not a", message)
+
+
+class TestValidationErrorDetails(unittest.TestCase):
+    # TODO: These really need unit tests for each individual validator, rather
+    #       than just these higher level tests.
+    def test_anyOf(self):
+        instance = 5
+        schema = {
+            "anyOf": [
+                {"minimum": 20},
+                {"type": "string"}
+            ]
+        }
+
+        validator = Draft4Validator(schema)
+        errors = list(validator.iter_errors(instance))
+        self.assertEqual(len(errors), 1)
+        e = errors[0]
+
+        self.assertEqual(e.validator, "anyOf")
+        self.assertEqual(e.validator_value, schema["anyOf"])
+        self.assertEqual(e.instance, instance)
+        self.assertEqual(e.schema, schema)
+        self.assertIsNone(e.parent)
+
+        self.assertEqual(e.path, deque([]))
+        self.assertEqual(e.relative_path, deque([]))
+        self.assertEqual(e.absolute_path, deque([]))
+
+        self.assertEqual(e.schema_path, deque(["anyOf"]))
+        self.assertEqual(e.relative_schema_path, deque(["anyOf"]))
+        self.assertEqual(e.absolute_schema_path, deque(["anyOf"]))
+
+        self.assertEqual(len(e.context), 2)
+
+        e1, e2 = sorted_errors(e.context)
+
+        self.assertEqual(e1.validator, "minimum")
+        self.assertEqual(e1.validator_value, schema["anyOf"][0]["minimum"])
+        self.assertEqual(e1.instance, instance)
+        self.assertEqual(e1.schema, schema["anyOf"][0])
+        self.assertIs(e1.parent, e)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e1.absolute_path, deque([]))
+        self.assertEqual(e1.relative_path, deque([]))
+
+        self.assertEqual(e1.schema_path, deque([0, "minimum"]))
+        self.assertEqual(e1.relative_schema_path, deque([0, "minimum"]))
+        self.assertEqual(
+            e1.absolute_schema_path, deque(["anyOf", 0, "minimum"]),
+        )
+
+        self.assertFalse(e1.context)
+
+        self.assertEqual(e2.validator, "type")
+        self.assertEqual(e2.validator_value, schema["anyOf"][1]["type"])
+        self.assertEqual(e2.instance, instance)
+        self.assertEqual(e2.schema, schema["anyOf"][1])
+        self.assertIs(e2.parent, e)
+
+        self.assertEqual(e2.path, deque([]))
+        self.assertEqual(e2.relative_path, deque([]))
+        self.assertEqual(e2.absolute_path, deque([]))
+
+        self.assertEqual(e2.schema_path, deque([1, "type"]))
+        self.assertEqual(e2.relative_schema_path, deque([1, "type"]))
+        self.assertEqual(e2.absolute_schema_path, deque(["anyOf", 1, "type"]))
+
+        self.assertEqual(len(e2.context), 0)
+
+    def test_type(self):
+        instance = {"foo": 1}
+        schema = {
+            "type": [
+                {"type": "integer"},
+                {
+                    "type": "object",
+                    "properties": {
+                        "foo": {"enum": [2]}
+                    }
+                }
+            ]
+        }
+
+        validator = Draft3Validator(schema)
+        errors = list(validator.iter_errors(instance))
+        self.assertEqual(len(errors), 1)
+        e = errors[0]
+
+        self.assertEqual(e.validator, "type")
+        self.assertEqual(e.validator_value, schema["type"])
+        self.assertEqual(e.instance, instance)
+        self.assertEqual(e.schema, schema)
+        self.assertIsNone(e.parent)
+
+        self.assertEqual(e.path, deque([]))
+        self.assertEqual(e.relative_path, deque([]))
+        self.assertEqual(e.absolute_path, deque([]))
+
+        self.assertEqual(e.schema_path, deque(["type"]))
+        self.assertEqual(e.relative_schema_path, deque(["type"]))
+        self.assertEqual(e.absolute_schema_path, deque(["type"]))
+
+        self.assertEqual(len(e.context), 2)
+
+        e1, e2 = sorted_errors(e.context)
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e1.validator_value, schema["type"][0]["type"])
+        self.assertEqual(e1.instance, instance)
+        self.assertEqual(e1.schema, schema["type"][0])
+        self.assertIs(e1.parent, e)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e1.relative_path, deque([]))
+        self.assertEqual(e1.absolute_path, deque([]))
+
+        self.assertEqual(e1.schema_path, deque([0, "type"]))
+        self.assertEqual(e1.relative_schema_path, deque([0, "type"]))
+        self.assertEqual(e1.absolute_schema_path, deque(["type", 0, "type"]))
+
+        self.assertFalse(e1.context)
+
+        self.assertEqual(e2.validator, "enum")
+        self.assertEqual(e2.validator_value, [2])
+        self.assertEqual(e2.instance, 1)
+        self.assertEqual(e2.schema, {u"enum" : [2]})
+        self.assertIs(e2.parent, e)
+
+        self.assertEqual(e2.path, deque(["foo"]))
+        self.assertEqual(e2.relative_path, deque(["foo"]))
+        self.assertEqual(e2.absolute_path, deque(["foo"]))
+
+        self.assertEqual(
+            e2.schema_path, deque([1, "properties", "foo", "enum"]),
+        )
+        self.assertEqual(
+            e2.relative_schema_path, deque([1, "properties", "foo", "enum"]),
+        )
+        self.assertEqual(
+            e2.absolute_schema_path,
+            deque(["type", 1, "properties", "foo", "enum"]),
+        )
+
+        self.assertFalse(e2.context)
+
+    def test_single_nesting(self):
+        instance = {"foo" : 2, "bar" : [1], "baz" : 15, "quux" : "spam"}
+        schema = {
+            "properties" : {
+                "foo" : {"type" : "string"},
+                "bar" : {"minItems" : 2},
+                "baz" : {"maximum" : 10, "enum" : [2, 4, 6, 8]},
+            }
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2, e3, e4 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["baz"]))
+        self.assertEqual(e3.path, deque(["baz"]))
+        self.assertEqual(e4.path, deque(["foo"]))
+
+        self.assertEqual(e1.relative_path, deque(["bar"]))
+        self.assertEqual(e2.relative_path, deque(["baz"]))
+        self.assertEqual(e3.relative_path, deque(["baz"]))
+        self.assertEqual(e4.relative_path, deque(["foo"]))
+
+        self.assertEqual(e1.absolute_path, deque(["bar"]))
+        self.assertEqual(e2.absolute_path, deque(["baz"]))
+        self.assertEqual(e3.absolute_path, deque(["baz"]))
+        self.assertEqual(e4.absolute_path, deque(["foo"]))
+
+        self.assertEqual(e1.validator, "minItems")
+        self.assertEqual(e2.validator, "enum")
+        self.assertEqual(e3.validator, "maximum")
+        self.assertEqual(e4.validator, "type")
+
+    def test_multiple_nesting(self):
+        instance = [1, {"foo" : 2, "bar" : {"baz" : [1]}}, "quux"]
+        schema = {
+            "type" : "string",
+            "items" : {
+                "type" : ["string", "object"],
+                "properties" : {
+                    "foo" : {"enum" : [1, 3]},
+                    "bar" : {
+                        "type" : "array",
+                        "properties" : {
+                            "bar" : {"required" : True},
+                            "baz" : {"minItems" : 2},
+                        }
+                    }
+                }
+            }
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2, e3, e4, e5, e6 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([]))
+        self.assertEqual(e2.path, deque([0]))
+        self.assertEqual(e3.path, deque([1, "bar"]))
+        self.assertEqual(e4.path, deque([1, "bar", "bar"]))
+        self.assertEqual(e5.path, deque([1, "bar", "baz"]))
+        self.assertEqual(e6.path, deque([1, "foo"]))
+
+        self.assertEqual(e1.schema_path, deque(["type"]))
+        self.assertEqual(e2.schema_path, deque(["items", "type"]))
+        self.assertEqual(
+            list(e3.schema_path), ["items", "properties", "bar", "type"],
+        )
+        self.assertEqual(
+            list(e4.schema_path),
+            ["items", "properties", "bar", "properties", "bar", "required"],
+        )
+        self.assertEqual(
+            list(e5.schema_path),
+            ["items", "properties", "bar", "properties", "baz", "minItems"]
+        )
+        self.assertEqual(
+            list(e6.schema_path), ["items", "properties", "foo", "enum"],
+        )
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "type")
+        self.assertEqual(e3.validator, "type")
+        self.assertEqual(e4.validator, "required")
+        self.assertEqual(e5.validator, "minItems")
+        self.assertEqual(e6.validator, "enum")
+
+    def test_additionalProperties(self):
+        instance = {"bar": "bar", "foo": 2}
+        schema = {
+            "additionalProperties" : {"type": "integer", "minimum": 5}
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["foo"]))
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_patternProperties(self):
+        instance = {"bar": 1, "foo": 2}
+        schema = {
+            "patternProperties" : {
+                "bar": {"type": "string"},
+                "foo": {"minimum": 5}
+            }
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque(["bar"]))
+        self.assertEqual(e2.path, deque(["foo"]))
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_additionalItems(self):
+        instance = ["foo", 1]
+        schema = {
+            "items": [],
+            "additionalItems" : {"type": "integer", "minimum": 5}
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([0]))
+        self.assertEqual(e2.path, deque([1]))
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+    def test_additionalItems_with_items(self):
+        instance = ["foo", "bar", 1]
+        schema = {
+            "items": [{}],
+            "additionalItems" : {"type": "integer", "minimum": 5}
+        }
+
+        validator = Draft3Validator(schema)
+        errors = validator.iter_errors(instance)
+        e1, e2 = sorted_errors(errors)
+
+        self.assertEqual(e1.path, deque([1]))
+        self.assertEqual(e2.path, deque([2]))
+
+        self.assertEqual(e1.validator, "type")
+        self.assertEqual(e2.validator, "minimum")
+
+
+class ValidatorTestMixin(object):
+    def setUp(self):
+        self.instance = mock.Mock()
+        self.schema = {}
+        self.resolver = mock.Mock()
+        self.validator = self.validator_class(self.schema)
+
+    def test_valid_instances_are_valid(self):
+        errors = iter([])
+
+        with mock.patch.object(
+            self.validator, "iter_errors", return_value=errors,
+        ):
+            self.assertTrue(
+                self.validator.is_valid(self.instance, self.schema)
+            )
+
+    def test_invalid_instances_are_not_valid(self):
+        errors = iter([mock.Mock()])
+
+        with mock.patch.object(
+            self.validator, "iter_errors", return_value=errors,
+        ):
+            self.assertFalse(
+                self.validator.is_valid(self.instance, self.schema)
+            )
+
+    def test_non_existent_properties_are_ignored(self):
+        instance, my_property, my_value = mock.Mock(), mock.Mock(), mock.Mock()
+        validate(instance=instance, schema={my_property : my_value})
+
+    def test_it_creates_a_ref_resolver_if_not_provided(self):
+        self.assertIsInstance(self.validator.resolver, RefResolver)
+
+    def test_it_delegates_to_a_ref_resolver(self):
+        resolver = RefResolver("", {})
+        schema = {"$ref" : mock.Mock()}
+
+        @contextmanager
+        def resolving():
+            yield {"type": "integer"}
+
+        with mock.patch.object(resolver, "resolving") as resolve:
+            resolve.return_value = resolving()
+            with self.assertRaises(ValidationError):
+                self.validator_class(schema, resolver=resolver).validate(None)
+
+        resolve.assert_called_once_with(schema["$ref"])
+
+    def test_is_type_is_true_for_valid_type(self):
+        self.assertTrue(self.validator.is_type("foo", "string"))
+
+    def test_is_type_is_false_for_invalid_type(self):
+        self.assertFalse(self.validator.is_type("foo", "array"))
+
+    def test_is_type_evades_bool_inheriting_from_int(self):
+        self.assertFalse(self.validator.is_type(True, "integer"))
+        self.assertFalse(self.validator.is_type(True, "number"))
+
+    def test_is_type_raises_exception_for_unknown_type(self):
+        with self.assertRaises(UnknownType):
+            self.validator.is_type("foo", object())
+
+
+class TestDraft3Validator(ValidatorTestMixin, unittest.TestCase):
+    validator_class = Draft3Validator
+
+    def test_is_type_is_true_for_any_type(self):
+        self.assertTrue(self.validator.is_valid(mock.Mock(), {"type": "any"}))
+
+    def test_is_type_does_not_evade_bool_if_it_is_being_tested(self):
+        self.assertTrue(self.validator.is_type(True, "boolean"))
+        self.assertTrue(self.validator.is_valid(True, {"type": "any"}))
+
+    def test_non_string_custom_types(self):
+        schema = {'type': [None]}
+        cls = self.validator_class(schema, types={None: type(None)})
+        cls.validate(None, schema)
+
+
+class TestDraft4Validator(ValidatorTestMixin, unittest.TestCase):
+    validator_class = Draft4Validator
+
+
+class TestBuiltinFormats(unittest.TestCase):
+    """
+    The built-in (specification-defined) formats do not raise type errors.
+
+    If an instance or value is not a string, it should be ignored.
+
+    """
+
+
+for format in FormatChecker.checkers:
+    def test(self, format=format):
+        v = Draft4Validator({"format": format}, format_checker=FormatChecker())
+        v.validate(123)
+
+    name = "test_{0}_ignores_non_strings".format(format)
+    test.__name__ = name
+    setattr(TestBuiltinFormats, name, test)
+    del test  # Ugh py.test. Stop discovering top level tests.
+
+
+class TestValidatorFor(unittest.TestCase):
+    def test_draft_3(self):
+        schema = {"$schema" : "http://json-schema.org/draft-03/schema"}
+        self.assertIs(validator_for(schema), Draft3Validator)
+
+        schema = {"$schema" : "http://json-schema.org/draft-03/schema#"}
+        self.assertIs(validator_for(schema), Draft3Validator)
+
+    def test_draft_4(self):
+        schema = {"$schema" : "http://json-schema.org/draft-04/schema"}
+        self.assertIs(validator_for(schema), Draft4Validator)
+
+        schema = {"$schema" : "http://json-schema.org/draft-04/schema#"}
+        self.assertIs(validator_for(schema), Draft4Validator)
+
+    def test_custom_validator(self):
+        Validator = create(meta_schema={"id" : "meta schema id"}, version="12")
+        schema = {"$schema" : "meta schema id"}
+        self.assertIs(validator_for(schema), Validator)
+
+    def test_validator_for_jsonschema_default(self):
+        self.assertIs(validator_for({}), Draft4Validator)
+
+    def test_validator_for_custom_default(self):
+        self.assertIs(validator_for({}, default=None), None)
+
+
+class TestValidate(unittest.TestCase):
+    def test_draft3_validator_is_chosen(self):
+        schema = {"$schema" : "http://json-schema.org/draft-03/schema#"}
+        with mock.patch.object(Draft3Validator, "check_schema") as chk_schema:
+            validate({}, schema)
+            chk_schema.assert_called_once_with(schema)
+        # Make sure it works without the empty fragment
+        schema = {"$schema" : "http://json-schema.org/draft-03/schema"}
+        with mock.patch.object(Draft3Validator, "check_schema") as chk_schema:
+            validate({}, schema)
+            chk_schema.assert_called_once_with(schema)
+
+    def test_draft4_validator_is_chosen(self):
+        schema = {"$schema" : "http://json-schema.org/draft-04/schema#"}
+        with mock.patch.object(Draft4Validator, "check_schema") as chk_schema:
+            validate({}, schema)
+            chk_schema.assert_called_once_with(schema)
+
+    def test_draft4_validator_is_the_default(self):
+        with mock.patch.object(Draft4Validator, "check_schema") as chk_schema:
+            validate({}, {})
+            chk_schema.assert_called_once_with({})
+
+
+class TestRefResolver(unittest.TestCase):
+
+    base_uri = ""
+    stored_uri = "foo://stored"
+    stored_schema = {"stored" : "schema"}
+
+    def setUp(self):
+        self.referrer = {}
+        self.store = {self.stored_uri : self.stored_schema}
+        self.resolver = RefResolver(self.base_uri, self.referrer, self.store)
+
+    def test_it_does_not_retrieve_schema_urls_from_the_network(self):
+        ref = Draft3Validator.META_SCHEMA["id"]
+        with mock.patch.object(self.resolver, "resolve_remote") as remote:
+            with self.resolver.resolving(ref) as resolved:
+                self.assertEqual(resolved, Draft3Validator.META_SCHEMA)
+        self.assertFalse(remote.called)
+
+    def test_it_resolves_local_refs(self):
+        ref = "#/properties/foo"
+        self.referrer["properties"] = {"foo" : object()}
+        with self.resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, self.referrer["properties"]["foo"])
+
+    def test_it_resolves_local_refs_with_id(self):
+        schema = {"id": "foo://bar/schema#", "a": {"foo": "bar"}}
+        resolver = RefResolver.from_schema(schema)
+        with resolver.resolving("#/a") as resolved:
+            self.assertEqual(resolved, schema["a"])
+        with resolver.resolving("foo://bar/schema#/a") as resolved:
+            self.assertEqual(resolved, schema["a"])
+
+    def test_it_retrieves_stored_refs(self):
+        with self.resolver.resolving(self.stored_uri) as resolved:
+            self.assertIs(resolved, self.stored_schema)
+
+        self.resolver.store["cached_ref"] = {"foo" : 12}
+        with self.resolver.resolving("cached_ref#/foo") as resolved:
+            self.assertEqual(resolved, 12)
+
+    def test_it_retrieves_unstored_refs_via_requests(self):
+        ref = "http://bar#baz"
+        schema = {"baz" : 12}
+
+        with mock.patch("jsonschema.validators.requests") as requests:
+            requests.get.return_value.json.return_value = schema
+            with self.resolver.resolving(ref) as resolved:
+                self.assertEqual(resolved, 12)
+        requests.get.assert_called_once_with("http://bar")
+
+    def test_it_retrieves_unstored_refs_via_urlopen(self):
+        ref = "http://bar#baz"
+        schema = {"baz" : 12}
+
+        with mock.patch("jsonschema.validators.requests", None):
+            with mock.patch("jsonschema.validators.urlopen") as urlopen:
+                urlopen.return_value.read.return_value = (
+                    json.dumps(schema).encode("utf8"))
+                with self.resolver.resolving(ref) as resolved:
+                    self.assertEqual(resolved, 12)
+        urlopen.assert_called_once_with("http://bar")
+
+    def test_it_can_construct_a_base_uri_from_a_schema(self):
+        schema = {"id" : "foo"}
+        resolver = RefResolver.from_schema(schema)
+        self.assertEqual(resolver.base_uri, "foo")
+        with resolver.resolving("") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("#") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("foo") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("foo#") as resolved:
+            self.assertEqual(resolved, schema)
+
+    def test_it_can_construct_a_base_uri_from_a_schema_without_id(self):
+        schema = {}
+        resolver = RefResolver.from_schema(schema)
+        self.assertEqual(resolver.base_uri, "")
+        with resolver.resolving("") as resolved:
+            self.assertEqual(resolved, schema)
+        with resolver.resolving("#") as resolved:
+            self.assertEqual(resolved, schema)
+
+    def test_custom_uri_scheme_handlers(self):
+        schema = {"foo": "bar"}
+        ref = "foo://bar"
+        foo_handler = mock.Mock(return_value=schema)
+        resolver = RefResolver("", {}, handlers={"foo": foo_handler})
+        with resolver.resolving(ref) as resolved:
+            self.assertEqual(resolved, schema)
+        foo_handler.assert_called_once_with(ref)
+
+    def test_cache_remote_on(self):
+        ref = "foo://bar"
+        foo_handler = mock.Mock()
+        resolver = RefResolver(
+            "", {}, cache_remote=True, handlers={"foo" : foo_handler},
+        )
+        with resolver.resolving(ref):
+            pass
+        with resolver.resolving(ref):
+            pass
+        foo_handler.assert_called_once_with(ref)
+
+    def test_cache_remote_off(self):
+        ref = "foo://bar"
+        foo_handler = mock.Mock()
+        resolver = RefResolver(
+            "", {}, cache_remote=False, handlers={"foo" : foo_handler},
+        )
+        with resolver.resolving(ref):
+            pass
+        with resolver.resolving(ref):
+            pass
+        self.assertEqual(foo_handler.call_count, 2)
+
+    def test_if_you_give_it_junk_you_get_a_resolution_error(self):
+        ref = "foo://bar"
+        foo_handler = mock.Mock(side_effect=ValueError("Oh no! What's this?"))
+        resolver = RefResolver("", {}, handlers={"foo" : foo_handler})
+        with self.assertRaises(RefResolutionError) as err:
+            with resolver.resolving(ref):
+                pass
+        self.assertEqual(str(err.exception), "Oh no! What's this?")
+
+
+def sorted_errors(errors):
+    def key(error):
+        return (
+            [str(e) for e in error.path],
+            [str(e) for e in error.schema_path]
+        )
+    return sorted(errors, key=key)
diff --git a/lib/spack/external/jsonschema/validators.py b/lib/spack/external/jsonschema/validators.py
new file mode 100644
index 0000000000..3e326844f4
--- /dev/null
+++ b/lib/spack/external/jsonschema/validators.py
@@ -0,0 +1,428 @@
+from __future__ import division
+
+import contextlib
+import json
+import numbers
+
+try:
+    import requests
+except ImportError:
+    requests = None
+
+from jsonschema import _utils, _validators
+from jsonschema.compat import (
+    Sequence, urljoin, urlsplit, urldefrag, unquote, urlopen,
+    str_types, int_types, iteritems,
+)
+from jsonschema.exceptions import ErrorTree  # Backwards compatibility  # noqa
+from jsonschema.exceptions import RefResolutionError, SchemaError, UnknownType
+
+
+_unset = _utils.Unset()
+
+validators = {}
+meta_schemas = _utils.URIDict()
+
+
+def validates(version):
+    """
+    Register the decorated validator for a ``version`` of the specification.
+
+    Registered validators and their meta schemas will be considered when
+    parsing ``$schema`` properties' URIs.
+
+    :argument str version: an identifier to use as the version's name
+    :returns: a class decorator to decorate the validator with the version
+
+    """
+
+    def _validates(cls):
+        validators[version] = cls
+        if u"id" in cls.META_SCHEMA:
+            meta_schemas[cls.META_SCHEMA[u"id"]] = cls
+        return cls
+    return _validates
+
+
+def create(meta_schema, validators=(), version=None, default_types=None):  # noqa
+    if default_types is None:
+        default_types = {
+            u"array" : list, u"boolean" : bool, u"integer" : int_types,
+            u"null" : type(None), u"number" : numbers.Number, u"object" : dict,
+            u"string" : str_types,
+        }
+
+    class Validator(object):
+        VALIDATORS = dict(validators)
+        META_SCHEMA = dict(meta_schema)
+        DEFAULT_TYPES = dict(default_types)
+
+        def __init__(
+            self, schema, types=(), resolver=None, format_checker=None,
+        ):
+            self._types = dict(self.DEFAULT_TYPES)
+            self._types.update(types)
+
+            if resolver is None:
+                resolver = RefResolver.from_schema(schema)
+
+            self.resolver = resolver
+            self.format_checker = format_checker
+            self.schema = schema
+
+        @classmethod
+        def check_schema(cls, schema):
+            for error in cls(cls.META_SCHEMA).iter_errors(schema):
+                raise SchemaError.create_from(error)
+
+        def iter_errors(self, instance, _schema=None):
+            if _schema is None:
+                _schema = self.schema
+
+            with self.resolver.in_scope(_schema.get(u"id", u"")):
+                ref = _schema.get(u"$ref")
+                if ref is not None:
+                    validators = [(u"$ref", ref)]
+                else:
+                    validators = iteritems(_schema)
+
+                for k, v in validators:
+                    validator = self.VALIDATORS.get(k)
+                    if validator is None:
+                        continue
+
+                    errors = validator(self, v, instance, _schema) or ()
+                    for error in errors:
+                        # set details if not already set by the called fn
+                        error._set(
+                            validator=k,
+                            validator_value=v,
+                            instance=instance,
+                            schema=_schema,
+                        )
+                        if k != u"$ref":
+                            error.schema_path.appendleft(k)
+                        yield error
+
+        def descend(self, instance, schema, path=None, schema_path=None):
+            for error in self.iter_errors(instance, schema):
+                if path is not None:
+                    error.path.appendleft(path)
+                if schema_path is not None:
+                    error.schema_path.appendleft(schema_path)
+                yield error
+
+        def validate(self, *args, **kwargs):
+            for error in self.iter_errors(*args, **kwargs):
+                raise error
+
+        def is_type(self, instance, type):
+            if type not in self._types:
+                raise UnknownType(type, instance, self.schema)
+            pytypes = self._types[type]
+
+            # bool inherits from int, so ensure bools aren't reported as ints
+            if isinstance(instance, bool):
+                pytypes = _utils.flatten(pytypes)
+                is_number = any(
+                    issubclass(pytype, numbers.Number) for pytype in pytypes
+                )
+                if is_number and bool not in pytypes:
+                    return False
+            return isinstance(instance, pytypes)
+
+        def is_valid(self, instance, _schema=None):
+            error = next(self.iter_errors(instance, _schema), None)
+            return error is None
+
+    if version is not None:
+        Validator = validates(version)(Validator)
+        Validator.__name__ = version.title().replace(" ", "") + "Validator"
+
+    return Validator
+
+
+def extend(validator, validators, version=None):
+    all_validators = dict(validator.VALIDATORS)
+    all_validators.update(validators)
+    return create(
+        meta_schema=validator.META_SCHEMA,
+        validators=all_validators,
+        version=version,
+        default_types=validator.DEFAULT_TYPES,
+    )
+
+
+Draft3Validator = create(
+    meta_schema=_utils.load_schema("draft3"),
+    validators={
+        u"$ref" : _validators.ref,
+        u"additionalItems" : _validators.additionalItems,
+        u"additionalProperties" : _validators.additionalProperties,
+        u"dependencies" : _validators.dependencies,
+        u"disallow" : _validators.disallow_draft3,
+        u"divisibleBy" : _validators.multipleOf,
+        u"enum" : _validators.enum,
+        u"extends" : _validators.extends_draft3,
+        u"format" : _validators.format,
+        u"items" : _validators.items,
+        u"maxItems" : _validators.maxItems,
+        u"maxLength" : _validators.maxLength,
+        u"maximum" : _validators.maximum,
+        u"minItems" : _validators.minItems,
+        u"minLength" : _validators.minLength,
+        u"minimum" : _validators.minimum,
+        u"multipleOf" : _validators.multipleOf,
+        u"pattern" : _validators.pattern,
+        u"patternProperties" : _validators.patternProperties,
+        u"properties" : _validators.properties_draft3,
+        u"type" : _validators.type_draft3,
+        u"uniqueItems" : _validators.uniqueItems,
+    },
+    version="draft3",
+)
+
+Draft4Validator = create(
+    meta_schema=_utils.load_schema("draft4"),
+    validators={
+        u"$ref" : _validators.ref,
+        u"additionalItems" : _validators.additionalItems,
+        u"additionalProperties" : _validators.additionalProperties,
+        u"allOf" : _validators.allOf_draft4,
+        u"anyOf" : _validators.anyOf_draft4,
+        u"dependencies" : _validators.dependencies,
+        u"enum" : _validators.enum,
+        u"format" : _validators.format,
+        u"items" : _validators.items,
+        u"maxItems" : _validators.maxItems,
+        u"maxLength" : _validators.maxLength,
+        u"maxProperties" : _validators.maxProperties_draft4,
+        u"maximum" : _validators.maximum,
+        u"minItems" : _validators.minItems,
+        u"minLength" : _validators.minLength,
+        u"minProperties" : _validators.minProperties_draft4,
+        u"minimum" : _validators.minimum,
+        u"multipleOf" : _validators.multipleOf,
+        u"not" : _validators.not_draft4,
+        u"oneOf" : _validators.oneOf_draft4,
+        u"pattern" : _validators.pattern,
+        u"patternProperties" : _validators.patternProperties,
+        u"properties" : _validators.properties_draft4,
+        u"required" : _validators.required_draft4,
+        u"type" : _validators.type_draft4,
+        u"uniqueItems" : _validators.uniqueItems,
+    },
+    version="draft4",
+)
+
+
+class RefResolver(object):
+    """
+    Resolve JSON References.
+
+    :argument str base_uri: URI of the referring document
+    :argument referrer: the actual referring document
+    :argument dict store: a mapping from URIs to documents to cache
+    :argument bool cache_remote: whether remote refs should be cached after
+        first resolution
+    :argument dict handlers: a mapping from URI schemes to functions that
+        should be used to retrieve them
+
+    """
+
+    def __init__(
+        self, base_uri, referrer, store=(), cache_remote=True, handlers=(),
+    ):
+        self.base_uri = base_uri
+        self.resolution_scope = base_uri
+        # This attribute is not used, it is for backwards compatibility
+        self.referrer = referrer
+        self.cache_remote = cache_remote
+        self.handlers = dict(handlers)
+
+        self.store = _utils.URIDict(
+            (id, validator.META_SCHEMA)
+            for id, validator in iteritems(meta_schemas)
+        )
+        self.store.update(store)
+        self.store[base_uri] = referrer
+
+    @classmethod
+    def from_schema(cls, schema, *args, **kwargs):
+        """
+        Construct a resolver from a JSON schema object.
+
+        :argument schema schema: the referring schema
+        :rtype: :class:`RefResolver`
+
+        """
+
+        return cls(schema.get(u"id", u""), schema, *args, **kwargs)
+
+    @contextlib.contextmanager
+    def in_scope(self, scope):
+        old_scope = self.resolution_scope
+        self.resolution_scope = urljoin(old_scope, scope)
+        try:
+            yield
+        finally:
+            self.resolution_scope = old_scope
+
+    @contextlib.contextmanager
+    def resolving(self, ref):
+        """
+        Context manager which resolves a JSON ``ref`` and enters the
+        resolution scope of this ref.
+
+        :argument str ref: reference to resolve
+
+        """
+
+        full_uri = urljoin(self.resolution_scope, ref)
+        uri, fragment = urldefrag(full_uri)
+        if not uri:
+            uri = self.base_uri
+
+        if uri in self.store:
+            document = self.store[uri]
+        else:
+            try:
+                document = self.resolve_remote(uri)
+            except Exception as exc:
+                raise RefResolutionError(exc)
+
+        old_base_uri, self.base_uri = self.base_uri, uri
+        try:
+            with self.in_scope(uri):
+                yield self.resolve_fragment(document, fragment)
+        finally:
+            self.base_uri = old_base_uri
+
+    def resolve_fragment(self, document, fragment):
+        """
+        Resolve a ``fragment`` within the referenced ``document``.
+
+        :argument document: the referrant document
+        :argument str fragment: a URI fragment to resolve within it
+
+        """
+
+        fragment = fragment.lstrip(u"/")
+        parts = unquote(fragment).split(u"/") if fragment else []
+
+        for part in parts:
+            part = part.replace(u"~1", u"/").replace(u"~0", u"~")
+
+            if isinstance(document, Sequence):
+                # Array indexes should be turned into integers
+                try:
+                    part = int(part)
+                except ValueError:
+                    pass
+            try:
+                document = document[part]
+            except (TypeError, LookupError):
+                raise RefResolutionError(
+                    "Unresolvable JSON pointer: %r" % fragment
+                )
+
+        return document
+
+    def resolve_remote(self, uri):
+        """
+        Resolve a remote ``uri``.
+
+        Does not check the store first, but stores the retrieved document in
+        the store if :attr:`RefResolver.cache_remote` is True.
+
+        .. note::
+
+            If the requests_ library is present, ``jsonschema`` will use it to
+            request the remote ``uri``, so that the correct encoding is
+            detected and used.
+
+            If it isn't, or if the scheme of the ``uri`` is not ``http`` or
+            ``https``, UTF-8 is assumed.
+
+        :argument str uri: the URI to resolve
+        :returns: the retrieved document
+
+        .. _requests: http://pypi.python.org/pypi/requests/
+
+        """
+
+        scheme = urlsplit(uri).scheme
+
+        if scheme in self.handlers:
+            result = self.handlers[scheme](uri)
+        elif (
+            scheme in [u"http", u"https"] and
+            requests and
+            getattr(requests.Response, "json", None) is not None
+        ):
+            # Requests has support for detecting the correct encoding of
+            # json over http
+            if callable(requests.Response.json):
+                result = requests.get(uri).json()
+            else:
+                result = requests.get(uri).json
+        else:
+            # Otherwise, pass off to urllib and assume utf-8
+            result = json.loads(urlopen(uri).read().decode("utf-8"))
+
+        if self.cache_remote:
+            self.store[uri] = result
+        return result
+
+
+def validator_for(schema, default=_unset):
+    if default is _unset:
+        default = Draft4Validator
+    return meta_schemas.get(schema.get(u"$schema", u""), default)
+
+
+def validate(instance, schema, cls=None, *args, **kwargs):
+    """
+    Validate an instance under the given schema.
+
+        >>> validate([2, 3, 4], {"maxItems" : 2})
+        Traceback (most recent call last):
+            ...
+        ValidationError: [2, 3, 4] is too long
+
+    :func:`validate` will first verify that the provided schema is itself
+    valid, since not doing so can lead to less obvious error messages and fail
+    in less obvious or consistent ways. If you know you have a valid schema
+    already or don't care, you might prefer using the
+    :meth:`~IValidator.validate` method directly on a specific validator
+    (e.g. :meth:`Draft4Validator.validate`).
+
+
+    :argument instance: the instance to validate
+    :argument schema: the schema to validate with
+    :argument cls: an :class:`IValidator` class that will be used to validate
+                   the instance.
+
+    If the ``cls`` argument is not provided, two things will happen in
+    accordance with the specification. First, if the schema has a
+    :validator:`$schema` property containing a known meta-schema [#]_ then the
+    proper validator will be used.  The specification recommends that all
+    schemas contain :validator:`$schema` properties for this reason. If no
+    :validator:`$schema` property is found, the default validator class is
+    :class:`Draft4Validator`.
+
+    Any other provided positional and keyword arguments will be passed on when
+    instantiating the ``cls``.
+
+    :raises:
+        :exc:`ValidationError` if the instance is invalid
+
+        :exc:`SchemaError` if the schema itself is invalid
+
+    .. rubric:: Footnotes
+    .. [#] known by a validator registered with :func:`validates`
+    """
+    if cls is None:
+        cls = validator_for(schema)
+    cls.check_schema(schema)
+    cls(schema, *args, **kwargs).validate(instance)
diff --git a/lib/spack/llnl/util/lang.py b/lib/spack/llnl/util/lang.py
index c84828951d..1c4d1ed623 100644
--- a/lib/spack/llnl/util/lang.py
+++ b/lib/spack/llnl/util/lang.py
@@ -26,6 +26,7 @@ import os
 import re
 import sys
 import functools
+import collections
 import inspect
 
 # Ignore emacs backups when listing modules
@@ -167,16 +168,32 @@ def has_method(cls, name):
     return False
 
 
-def memoized(obj):
+class memoized(object):
     """Decorator that caches the results of a function, storing them
        in an attribute of that function."""
-    cache = obj.cache = {}
-    @functools.wraps(obj)
-    def memoizer(*args, **kwargs):
-        if args not in cache:
-            cache[args] = obj(*args, **kwargs)
-        return cache[args]
-    return memoizer
+    def __init__(self, func):
+        self.func = func
+        self.cache = {}
+
+
+    def __call__(self, *args):
+        if not isinstance(args, collections.Hashable):
+            # Not hashable, so just call the function.
+            return self.func(*args)
+
+        if args not in self.cache:
+            self.cache[args] = self.func(*args)
+        return self.cache[args]
+
+
+    def __get__(self, obj, objtype):
+        """Support instance methods."""
+        return functools.partial(self.__call__, obj)
+
+
+    def clear(self):
+        """Expunge cache so that self.func will be called again."""
+        self.cache.clear()
 
 
 def list_modules(directory, **kwargs):
diff --git a/lib/spack/llnl/util/tty/__init__.py b/lib/spack/llnl/util/tty/__init__.py
index 203f429a48..3ecd3a4ac2 100644
--- a/lib/spack/llnl/util/tty/__init__.py
+++ b/lib/spack/llnl/util/tty/__init__.py
@@ -63,35 +63,46 @@ def msg(message, *args):
 def info(message, *args, **kwargs):
     format = kwargs.get('format', '*b')
     stream = kwargs.get('stream', sys.stdout)
+    wrap   = kwargs.get('wrap', False)
 
     cprint("@%s{==>} %s" % (format, cescape(str(message))), stream=stream)
     for arg in args:
-        lines = textwrap.wrap(
-            str(arg), initial_indent=indent, subsequent_indent=indent)
-        for line in lines:
-            stream.write(line + '\n')
+        if wrap:
+            lines = textwrap.wrap(
+                str(arg), initial_indent=indent, subsequent_indent=indent)
+            for line in lines:
+                stream.write(line + '\n')
+        else:
+            stream.write(indent + str(arg) + '\n')
 
 
-def verbose(message, *args):
+def verbose(message, *args, **kwargs):
     if _verbose:
-        info(message, *args, format='c')
+        kwargs.setdefault('format', 'c')
+        info(message, *args, **kwargs)
 
 
-def debug(message, *args):
+def debug(message, *args, **kwargs):
     if _debug:
-        info(message, *args, format='g', stream=sys.stderr)
+        kwargs.setdefault('format', 'g')
+        kwargs.setdefault('stream', sys.stderr)
+        info(message, *args, **kwargs)
 
 
-def error(message, *args):
-    info("Error: " + str(message), *args, format='*r', stream=sys.stderr)
+def error(message, *args, **kwargs):
+    kwargs.setdefault('format', '*r')
+    kwargs.setdefault('stream', sys.stderr)
+    info("Error: " + str(message), *args, **kwargs)
 
 
-def warn(message, *args):
-    info("Warning: " + str(message), *args, format='*Y', stream=sys.stderr)
+def warn(message, *args, **kwargs):
+    kwargs.setdefault('format', '*Y')
+    kwargs.setdefault('stream', sys.stderr)
+    info("Warning: " + str(message), *args, **kwargs)
 
 
-def die(message, *args):
-    error(message, *args)
+def die(message, *args, **kwargs):
+    error(message, *args, **kwargs)
     sys.exit(1)
 
 
diff --git a/lib/spack/llnl/util/tty/colify.py b/lib/spack/llnl/util/tty/colify.py
index 5545cf0311..47c3cc4f8f 100644
--- a/lib/spack/llnl/util/tty/colify.py
+++ b/lib/spack/llnl/util/tty/colify.py
@@ -210,6 +210,13 @@ def colify(elts, **options):
 
 
 def colify_table(table, **options):
+    """Version of colify() for data expressed in rows, (list of lists).
+
+       Same as regular colify but takes a list of lists, where each
+       sub-list must be the same length, and each is interpreted as a
+       row in a table.  Regular colify displays a sequential list of
+       values in columns.
+    """
     if table is None:
         raise TypeError("Can't call colify_table on NoneType")
     elif not table or not table[0]:
diff --git a/lib/spack/spack/__init__.py b/lib/spack/spack/__init__.py
index 92cb417a85..ab78ecef30 100644
--- a/lib/spack/spack/__init__.py
+++ b/lib/spack/spack/__init__.py
@@ -23,9 +23,11 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import os
+import sys
 import tempfile
 import getpass
 from llnl.util.filesystem import *
+import llnl.util.tty as tty
 
 # This lives in $prefix/lib/spack/spack/__file__
 spack_root = ancestor(__file__, 4)
@@ -42,6 +44,7 @@ test_path      = join_path(module_path, "test")
 hooks_path     = join_path(module_path, "hooks")
 var_path       = join_path(spack_root, "var", "spack")
 stage_path     = join_path(var_path, "stage")
+repos_path     = join_path(var_path, "repos")
 share_path     = join_path(spack_root, "share", "spack")
 
 prefix = spack_root
@@ -50,11 +53,14 @@ install_path   = join_path(opt_path, "spack")
 etc_path       = join_path(prefix, "etc")
 
 #
-# Set up the packages database.
+# Set up the default packages database.
 #
-from spack.packages import PackageDB
-packages_path = join_path(var_path, "packages")
-db = PackageDB(packages_path)
+import spack.repository
+try:
+    repo = spack.repository.RepoPath()
+    sys.meta_path.append(repo)
+except spack.error.SpackError, e:
+    tty.die('while initializing Spack RepoPath:', e.message)
 
 #
 # Set up the installed packages database
@@ -63,13 +69,10 @@ from spack.database import Database
 installed_db = Database(install_path)
 
 #
-# Paths to mock files for testing.
+# Paths to built-in Spack repositories.
 #
-mock_packages_path = join_path(var_path, "mock_packages")
-
-mock_config_path = join_path(var_path, "mock_configs")
-mock_site_config = join_path(mock_config_path, "site_spackconfig")
-mock_user_config = join_path(mock_config_path, "user_spackconfig")
+packages_path      = join_path(repos_path, "builtin")
+mock_packages_path = join_path(repos_path, "builtin.mock")
 
 #
 # This controls how spack lays out install prefixes and
@@ -149,7 +152,7 @@ sys_type = None
 # When packages call 'from spack import *', this extra stuff is brought in.
 #
 # Spack internal code should call 'import spack' and accesses other
-# variables (spack.db, paths, etc.) directly.
+# variables (spack.repo, paths, etc.) directly.
 #
 # TODO: maybe this should be separated out and should go in build_environment.py?
 # TODO: it's not clear where all the stuff that needs to be included in packages
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index 84c2f6015b..b2db83acb7 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -173,7 +173,7 @@ def set_build_environment_variables(pkg):
     path_set("PKG_CONFIG_PATH", pkg_config_dirs)
 
 
-def set_module_variables_for_package(pkg):
+def set_module_variables_for_package(pkg, m):
     """Populate the module scope of install() with some useful functions.
        This makes things easier for package writers.
     """
@@ -244,11 +244,32 @@ def get_rpaths(pkg):
     return rpaths
 
 
+def parent_class_modules(cls):
+    """Get list of super class modules that are all descend from spack.Package"""
+    if not issubclass(cls, spack.Package) or issubclass(spack.Package, cls):
+        return []
+    result = []
+    module = sys.modules.get(cls.__module__)
+    if module:
+        result = [ module ]
+    for c in cls.__bases__:
+        result.extend(parent_class_modules(c))
+    return result
+
+
 def setup_package(pkg):
     """Execute all environment setup routines."""
     set_compiler_environment_variables(pkg)
     set_build_environment_variables(pkg)
-    set_module_variables_for_package(pkg)
+
+    # If a user makes their own package repo, e.g.
+    # spack.repos.mystuff.libelf.Libelf, and they inherit from
+    # an existing class like spack.repos.original.libelf.Libelf,
+    # then set the module variables for both classes so the
+    # parent class can still use them if it gets called.
+    modules = parent_class_modules(pkg.__class__)
+    for mod in modules:
+        set_module_variables_for_package(pkg, mod)
 
     # Allow dependencies to set up environment as well.
     for dep_spec in pkg.spec.traverse(root=False):
diff --git a/lib/spack/spack/cmd/__init__.py b/lib/spack/spack/cmd/__init__.py
index 926e7ac14a..6c635a1e6c 100644
--- a/lib/spack/spack/cmd/__init__.py
+++ b/lib/spack/spack/cmd/__init__.py
@@ -31,6 +31,15 @@ from llnl.util.lang import attr_setdefault
 
 import spack
 import spack.spec
+import spack.config
+
+#
+# Settings for commands that modify configuration
+#
+# Commands that modify confguration By default modify the *highest* priority scope.
+default_modify_scope = spack.config.highest_precedence_scope().name
+# Commands that list confguration list *all* scopes by default.
+default_list_scope = None
 
 # cmd has a submodule called "list" so preserve the python list module
 python_list = list
diff --git a/lib/spack/spack/cmd/checksum.py b/lib/spack/spack/cmd/checksum.py
index 6b7022a7a1..b1ad89dbb8 100644
--- a/lib/spack/spack/cmd/checksum.py
+++ b/lib/spack/spack/cmd/checksum.py
@@ -81,7 +81,7 @@ def get_checksums(versions, urls, **kwargs):
 
 def checksum(parser, args):
     # get the package we're going to generate checksums for
-    pkg = spack.db.get(args.package)
+    pkg = spack.repo.get(args.package)
 
     # If the user asked for specific versions, use those.
     if args.versions:
diff --git a/lib/spack/spack/cmd/clean.py b/lib/spack/spack/cmd/clean.py
index c3409887fb..6e7179122c 100644
--- a/lib/spack/spack/cmd/clean.py
+++ b/lib/spack/spack/cmd/clean.py
@@ -42,5 +42,5 @@ def clean(parser, args):
 
     specs = spack.cmd.parse_specs(args.packages, concretize=True)
     for spec in specs:
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         package.do_clean()
diff --git a/lib/spack/spack/cmd/compiler.py b/lib/spack/spack/cmd/compiler.py
index 589ca87fb5..75b51f6b49 100644
--- a/lib/spack/spack/cmd/compiler.py
+++ b/lib/spack/spack/cmd/compiler.py
@@ -22,6 +22,7 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
+import sys
 import argparse
 
 import llnl.util.tty as tty
@@ -41,17 +42,32 @@ def setup_parser(subparser):
     sp = subparser.add_subparsers(
         metavar='SUBCOMMAND', dest='compiler_command')
 
-    update_parser = sp.add_parser(
-        'add', help='Add compilers to the Spack configuration.')
-    update_parser.add_argument('add_paths', nargs=argparse.REMAINDER)
-
-    remove_parser = sp.add_parser('remove', help='remove compiler')
-    remove_parser.add_argument('path')
-
-    list_parser   = sp.add_parser('list', help='list available compilers')
-
-    info_parser   = sp.add_parser('info', help='Show compiler paths.')
+    scopes = spack.config.config_scopes
+
+    # Add
+    add_parser = sp.add_parser('add', help='Add compilers to the Spack configuration.')
+    add_parser.add_argument('add_paths', nargs=argparse.REMAINDER)
+    add_parser.add_argument('--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+                            help="Configuration scope to modify.")
+
+    # Remove
+    remove_parser = sp.add_parser('remove', aliases=['rm'], help='Remove compiler by spec.')
+    remove_parser.add_argument(
+        '-a', '--all', action='store_true', help='Remove ALL compilers that match spec.')
+    remove_parser.add_argument('compiler_spec')
+    remove_parser.add_argument('--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+                               help="Configuration scope to modify.")
+
+    # List
+    list_parser = sp.add_parser('list', help='list available compilers')
+    list_parser.add_argument('--scope', choices=scopes, default=spack.cmd.default_list_scope,
+                             help="Configuration scope to read from.")
+
+    # Info
+    info_parser = sp.add_parser('info', help='Show compiler paths.')
     info_parser.add_argument('compiler_spec')
+    info_parser.add_argument('--scope', choices=scopes, default=spack.cmd.default_list_scope,
+                             help="Configuration scope to read from.")
 
 
 def compiler_add(args):
@@ -62,26 +78,40 @@ def compiler_add(args):
         paths = get_path('PATH')
 
     compilers = [c for c in spack.compilers.find_compilers(*args.add_paths)
-                 if c.spec not in spack.compilers.all_compilers()]
+                 if c.spec not in spack.compilers.all_compilers(scope=args.scope)]
 
     if compilers:
-        spack.compilers.add_compilers_to_config('user', *compilers)
+        spack.compilers.add_compilers_to_config(compilers, scope=args.scope)
         n = len(compilers)
-        tty.msg("Added %d new compiler%s to %s" % (
-            n, 's' if n > 1 else '', spack.config.get_config_scope_filename('user', 'compilers')))
+        s = 's' if n > 1 else ''
+        filename = spack.config.get_config_filename(args.scope, 'compilers')
+        tty.msg("Added %d new compiler%s to %s" % (n, s, filename))
         colify(reversed(sorted(c.spec for c in compilers)), indent=4)
     else:
         tty.msg("Found no new compilers")
 
 
 def compiler_remove(args):
-    pass
+    cspec = CompilerSpec(args.compiler_spec)
+    compilers = spack.compilers.compilers_for_spec(cspec, scope=args.scope)
+
+    if not compilers:
+        tty.die("No compilers match spec %s." % cspec)
+    elif not args.all and len(compilers) > 1:
+        tty.error("Multiple compilers match spec %s. Choose one:" % cspec)
+        colify(reversed(sorted([c.spec for c in compilers])), indent=4)
+        tty.msg("Or, you can use `spack compiler remove -a` to remove all of them.")
+        sys.exit(1)
+
+    for compiler in compilers:
+        spack.compilers.remove_compiler_from_config(compiler.spec, scope=args.scope)
+        tty.msg("Removed compiler %s." % compiler.spec)
 
 
 def compiler_info(args):
     """Print info about all compilers matching a spec."""
     cspec = CompilerSpec(args.compiler_spec)
-    compilers = spack.compilers.compilers_for_spec(cspec)
+    compilers = spack.compilers.compilers_for_spec(cspec, scope=args.scope)
 
     if not compilers:
         tty.error("No compilers match spec %s." % cspec)
@@ -96,7 +126,7 @@ def compiler_info(args):
 
 def compiler_list(args):
     tty.msg("Available compilers")
-    index = index_by(spack.compilers.all_compilers(), 'name')
+    index = index_by(spack.compilers.all_compilers(scope=args.scope), 'name')
     for i, (name, compilers) in enumerate(index.items()):
         if i >= 1: print
 
@@ -108,6 +138,7 @@ def compiler_list(args):
 def compiler(parser, args):
     action = { 'add'    : compiler_add,
                'remove' : compiler_remove,
+               'rm'     : compiler_remove,
                'info'   : compiler_info,
                'list'   : compiler_list }
     action[args.compiler_command](args)
diff --git a/lib/spack/spack/cmd/compilers.py b/lib/spack/spack/cmd/compilers.py
index c485a910eb..7e09016f2d 100644
--- a/lib/spack/spack/cmd/compilers.py
+++ b/lib/spack/spack/cmd/compilers.py
@@ -26,9 +26,14 @@ import llnl.util.tty as tty
 from llnl.util.tty.colify import colify
 from llnl.util.lang import index_by
 
+import spack
 from spack.cmd.compiler import compiler_list
 
 description = "List available compilers. Same as 'spack compiler list'."
 
+def setup_parser(subparser):
+    subparser.add_argument('--scope', choices=spack.config.config_scopes,
+                           help="Configuration scope to read/modify.")
+
 def compilers(parser, args):
     compiler_list(args)
diff --git a/lib/spack/spack/cmd/config.py b/lib/spack/spack/cmd/config.py
index a6e914131e..5e6d4e4d7d 100644
--- a/lib/spack/spack/cmd/config.py
+++ b/lib/spack/spack/cmd/config.py
@@ -44,22 +44,22 @@ def setup_parser(subparser):
     sp = subparser.add_subparsers(metavar='SUBCOMMAND', dest='config_command')
 
     get_parser = sp.add_parser('get', help='Print configuration values.')
-    get_parser.add_argument('category', help="Configuration category to print.")
+    get_parser.add_argument('section', help="Configuration section to print.")
 
     edit_parser = sp.add_parser('edit', help='Edit configuration file.')
-    edit_parser.add_argument('category', help="Configuration category to edit")
+    edit_parser.add_argument('section', help="Configuration section to edit")
 
 
 def config_get(args):
-    spack.config.print_category(args.category)
+    spack.config.print_section(args.section)
 
 
 def config_edit(args):
     if not args.scope:
         args.scope = 'user'
-    if not args.category:
-        args.category = None
-    config_file = spack.config.get_config_scope_filename(args.scope, args.category)
+    if not args.section:
+        args.section = None
+    config_file = spack.config.get_config_filename(args.scope, args.section)
     spack.editor(config_file)
 
 
diff --git a/lib/spack/spack/cmd/create.py b/lib/spack/spack/cmd/create.py
index 9ecb709110..7cea39cb55 100644
--- a/lib/spack/spack/cmd/create.py
+++ b/lib/spack/spack/cmd/create.py
@@ -36,7 +36,9 @@ import spack.cmd
 import spack.cmd.checksum
 import spack.url
 import spack.util.web
+from spack.spec import Spec
 from spack.util.naming import *
+from spack.repository import Repo, RepoError
 import spack.util.crypto as crypto
 
 from spack.util.executable import which
@@ -85,18 +87,34 @@ ${versions}
 """)
 
 
+def make_version_calls(ver_hash_tuples):
+    """Adds a version() call to the package for each version found."""
+    max_len = max(len(str(v)) for v, h in ver_hash_tuples)
+    format = "    version(%%-%ds, '%%s')" % (max_len + 2)
+    return '\n'.join(format % ("'%s'" % v, h) for v, h in ver_hash_tuples)
+
+
 def setup_parser(subparser):
     subparser.add_argument('url', nargs='?', help="url of package archive")
     subparser.add_argument(
-        '--keep-stage', action='store_true', dest='keep_stage',
+        '--keep-stage', action='store_true',
         help="Don't clean up staging area when command completes.")
     subparser.add_argument(
-        '-n', '--name', dest='alternate_name', default=None,
+        '-n', '--name', dest='alternate_name', default=None, metavar='NAME',
         help="Override the autodetected name for the created package.")
     subparser.add_argument(
+        '-r', '--repo', default=None,
+        help="Path to a repository where the package should be created.")
+    subparser.add_argument(
+        '-N', '--namespace',
+        help="Specify a namespace for the package. Must be the namespace of "
+        "a repository registered with Spack.")
+    subparser.add_argument(
         '-f', '--force', action='store_true', dest='force',
         help="Overwrite any existing package file with the same name.")
 
+    setup_parser.subparser = subparser
+
 
 class ConfigureGuesser(object):
     def __call__(self, stage):
@@ -134,16 +152,7 @@ class ConfigureGuesser(object):
         self.build_system = build_system
 
 
-def make_version_calls(ver_hash_tuples):
-    """Adds a version() call to the package for each version found."""
-    max_len = max(len(str(v)) for v, h in ver_hash_tuples)
-    format = "    version(%%-%ds, '%%s')" % (max_len + 2)
-    return '\n'.join(format % ("'%s'" % v, h) for v, h in ver_hash_tuples)
-
-
-def create(parser, args):
-    url = args.url
-
+def guess_name_and_version(url, args):
     # Try to deduce name and version of the new package from the URL
     version = spack.url.parse_version(url)
     if not version:
@@ -160,12 +169,52 @@ def create(parser, args):
             tty.die("Couldn't guess a name for this package. Try running:", "",
                     "spack create --name <name> <url>")
 
-    if not valid_module_name(name):
+    if not valid_fully_qualified_module_name(name):
         tty.die("Package name can only contain A-Z, a-z, 0-9, '_' and '-'")
 
-    tty.msg("This looks like a URL for %s version %s." % (name, version))
-    tty.msg("Creating template for package %s" % name)
+    return name, version
+
 
+def find_repository(spec, args):
+    # figure out namespace for spec
+    if spec.namespace and args.namespace and spec.namespace != args.namespace:
+        tty.die("Namespaces '%s' and '%s' do not match." % (spec.namespace, args.namespace))
+
+    if not spec.namespace and args.namespace:
+        spec.namespace = args.namespace
+
+    # Figure out where the new package should live.
+    repo_path = args.repo
+    if repo_path is not None:
+        try:
+            repo = Repo(repo_path)
+            if spec.namespace and spec.namespace != repo.namespace:
+                tty.die("Can't create package with namespace %s in repo with namespace %s."
+                        % (spec.namespace, repo.namespace))
+        except RepoError as e:
+            tty.die(str(e))
+    else:
+        if spec.namespace:
+            repo = spack.repo.get_repo(spec.namespace, None)
+            if not repo:
+                tty.die("Unknown namespace: %s" % spec.namespace)
+        else:
+            repo = spack.repo.first_repo()
+
+    # Set the namespace on the spec if it's not there already
+    if not spec.namespace:
+        spec.namespace = repo.namespace
+
+    return repo
+
+
+def fetch_tarballs(url, name, args):
+    """Try to find versions of the supplied archive by scraping the web.
+
+    Prompts the user to select how many to download if many are found.
+
+
+    """
     versions = spack.util.web.find_versions_of_archive(url)
     rkeys = sorted(versions.keys(), reverse=True)
     versions = OrderedDict(zip(rkeys, (versions[v] for v in rkeys)))
@@ -184,13 +233,35 @@ def create(parser, args):
             default=5, abort='q')
 
         if not archives_to_fetch:
-            tty.msg("Aborted.")
-            return
+            tty.die("Aborted.")
+
+    sorted_versions = sorted(versions.keys(), reverse=True)
+    sorted_urls = [versions[v] for v in sorted_versions]
+    return sorted_versions[:archives_to_fetch], sorted_urls[:archives_to_fetch]
+
+
+def create(parser, args):
+    url = args.url
+    if not url:
+        setup_parser.subparser.print_help()
+        return
+
+    # Figure out a name and repo for the package.
+    name, version = guess_name_and_version(url, args)
+    spec = Spec(name)
+    name = spec.name  # factors out namespace, if any
+    repo = find_repository(spec, args)
+
+    tty.msg("This looks like a URL for %s version %s." % (name, version))
+    tty.msg("Creating template for package %s" % name)
+
+    # Fetch tarballs (prompting user if necessary)
+    versions, urls = fetch_tarballs(url, name, args)
 
+    # Try to guess what configure system is used.
     guesser = ConfigureGuesser()
     ver_hash_tuples = spack.cmd.checksum.get_checksums(
-        versions.keys()[:archives_to_fetch],
-        [versions[v] for v in versions.keys()[:archives_to_fetch]],
+        versions, urls,
         first_stage_function=guesser,
         keep_stage=args.keep_stage)
 
@@ -202,7 +273,7 @@ def create(parser, args):
         name = 'py-%s' % name
 
     # Create a directory for the new package.
-    pkg_path = spack.db.filename_for_package_name(name)
+    pkg_path = repo.filename_for_package_name(name)
     if os.path.exists(pkg_path) and not args.force:
         tty.die("%s already exists." % pkg_path)
     else:
diff --git a/lib/spack/spack/cmd/diy.py b/lib/spack/spack/cmd/diy.py
index ebe8424f09..9df53312f8 100644
--- a/lib/spack/spack/cmd/diy.py
+++ b/lib/spack/spack/cmd/diy.py
@@ -61,7 +61,7 @@ def diy(self, args):
     # Take a write lock before checking for existence.
     with spack.installed_db.write_transaction():
         spec = specs[0]
-        if not spack.db.exists(spec.name):
+        if not spack.repo.exists(spec.name):
             tty.warn("No such package: %s" % spec.name)
             create = tty.get_yes_or_no("Create this package?", default=False)
             if not create:
@@ -69,14 +69,14 @@ def diy(self, args):
                 sys.exit(1)
             else:
                 tty.msg("Running 'spack edit -f %s'" % spec.name)
-                edit_package(spec.name, True)
+                edit_package(spec.name, spack.repo.first_repo(), None, True)
                 return
 
         if not spec.version.concrete:
             tty.die("spack diy spec must have a single, concrete version.")
 
         spec.concretize()
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
 
         if package.installed:
             tty.error("Already installed in %s" % package.prefix)
diff --git a/lib/spack/spack/cmd/edit.py b/lib/spack/spack/cmd/edit.py
index b168d967b9..a20e40df9b 100644
--- a/lib/spack/spack/cmd/edit.py
+++ b/lib/spack/spack/cmd/edit.py
@@ -30,6 +30,8 @@ from llnl.util.filesystem import mkdirp, join_path
 
 import spack
 import spack.cmd
+from spack.spec import Spec
+from spack.repository import Repo
 from spack.util.naming import mod_to_class
 
 description = "Open package files in $EDITOR"
@@ -53,9 +55,16 @@ class ${class_name}(Package):
 """)
 
 
-def edit_package(name, force=False):
-    path = spack.db.filename_for_package_name(name)
+def edit_package(name, repo_path, namespace, force=False):
+    if repo_path:
+        repo = Repo(repo_path)
+    elif namespace:
+        repo = spack.repo.get_repo(namespace)
+    else:
+        repo = spack.repo
+    path = repo.filename_for_package_name(name)
 
+    spec = Spec(name)
     if os.path.exists(path):
         if not os.path.isfile(path):
             tty.die("Something's wrong.  '%s' is not a file!" % path)
@@ -63,13 +72,13 @@ def edit_package(name, force=False):
             tty.die("Insufficient permissions on '%s'!" % path)
     elif not force:
         tty.die("No package '%s'.  Use spack create, or supply -f/--force "
-                "to edit a new file." % name)
+                "to edit a new file." % spec.name)
     else:
         mkdirp(os.path.dirname(path))
         with open(path, "w") as pkg_file:
             pkg_file.write(
                 package_template.substitute(
-                    name=name, class_name=mod_to_class(name)))
+                    name=spec.name, class_name=mod_to_class(spec.name)))
 
     spack.editor(path)
 
@@ -78,9 +87,26 @@ def setup_parser(subparser):
     subparser.add_argument(
         '-f', '--force', dest='force', action='store_true',
         help="Open a new file in $EDITOR even if package doesn't exist.")
-    subparser.add_argument(
-        '-c', '--command', dest='edit_command', action='store_true',
-        help="Edit the command with the supplied name instead of a package.")
+
+    excl_args = subparser.add_mutually_exclusive_group()
+
+    # Various filetypes you can edit directly from the cmd line.
+    excl_args.add_argument(
+        '-c', '--command', dest='path', action='store_const',
+        const=spack.cmd.command_path, help="Edit the command with the supplied name.")
+    excl_args.add_argument(
+        '-t', '--test', dest='path', action='store_const',
+        const=spack.test_path, help="Edit the test with the supplied name.")
+    excl_args.add_argument(
+        '-m', '--module', dest='path', action='store_const',
+        const=spack.module_path, help="Edit the main spack module with the supplied name.")
+
+    # Options for editing packages
+    excl_args.add_argument(
+        '-r', '--repo', default=None, help="Path to repo to edit package in.")
+    excl_args.add_argument(
+        '-N', '--namespace', default=None, help="Namespace of package to edit.")
+
     subparser.add_argument(
         'name', nargs='?', default=None, help="name of package to edit")
 
@@ -88,19 +114,17 @@ def setup_parser(subparser):
 def edit(parser, args):
     name = args.name
 
-    if args.edit_command:
-        if not name:
-            path = spack.cmd.command_path
-        else:
-            path = join_path(spack.cmd.command_path, name + ".py")
-            if not os.path.exists(path):
+    path = spack.packages_path
+    if args.path:
+        path = args.path
+        if name:
+            path = join_path(path, name + ".py")
+            if not args.force and not os.path.exists(path):
                 tty.die("No command named '%s'." % name)
         spack.editor(path)
 
+    elif name:
+        edit_package(name, args.repo, args.namespace, args.force)
     else:
         # By default open the directory where packages or commands live.
-        if not name:
-            path = spack.packages_path
-            spack.editor(path)
-        else:
-            edit_package(name, args.force)
+        spack.editor(path)
diff --git a/lib/spack/spack/cmd/extensions.py b/lib/spack/spack/cmd/extensions.py
index 2ce6f406ca..ccb0fe4e1f 100644
--- a/lib/spack/spack/cmd/extensions.py
+++ b/lib/spack/spack/cmd/extensions.py
@@ -74,8 +74,7 @@ def extensions(parser, args):
 
     #
     # List package names of extensions
-    #
-    extensions = spack.db.extensions_for(spec)
+    extensions = spack.repo.extensions_for(spec)
     if not extensions:
         tty.msg("%s has no extensions." % spec.cshort_spec)
         return
diff --git a/lib/spack/spack/cmd/fetch.py b/lib/spack/spack/cmd/fetch.py
index 57d6f6b63b..adad545cae 100644
--- a/lib/spack/spack/cmd/fetch.py
+++ b/lib/spack/spack/cmd/fetch.py
@@ -52,10 +52,10 @@ def fetch(parser, args):
         if args.missing or args.dependencies:
             to_fetch = set()
             for s in spec.traverse():
-                package = spack.db.get(s)
+                package = spack.repo.get(s)
                 if args.missing and package.installed:
                     continue
                 package.do_fetch()
 
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         package.do_fetch()
diff --git a/lib/spack/spack/cmd/find.py b/lib/spack/spack/cmd/find.py
index c7a376fd8d..714f1d514b 100644
--- a/lib/spack/spack/cmd/find.py
+++ b/lib/spack/spack/cmd/find.py
@@ -41,6 +41,9 @@ description ="Find installed spack packages"
 def setup_parser(subparser):
     format_group = subparser.add_mutually_exclusive_group()
     format_group.add_argument(
+        '-s', '--short', action='store_const', dest='mode', const='short',
+        help='Show only specs (default)')
+    format_group.add_argument(
         '-p', '--paths', action='store_const', dest='mode', const='paths',
         help='Show paths to package install directories')
     format_group.add_argument(
@@ -48,21 +51,24 @@ def setup_parser(subparser):
         help='Show full dependency DAG of installed packages')
 
     subparser.add_argument(
-        '-l', '--long', action='store_true', dest='long',
+        '-l', '--long', action='store_true',
         help='Show dependency hashes as well as versions.')
     subparser.add_argument(
-        '-L', '--very-long', action='store_true', dest='very_long',
+        '-L', '--very-long', action='store_true',
         help='Show dependency hashes as well as versions.')
 
     subparser.add_argument(
-        '-u', '--unknown', action='store_true', dest='unknown',
+        '-u', '--unknown', action='store_true',
         help='Show only specs Spack does not have a package for.')
     subparser.add_argument(
-        '-m', '--missing', action='store_true', dest='missing',
+        '-m', '--missing', action='store_true',
         help='Show missing dependencies as well as installed specs.')
     subparser.add_argument(
-        '-M', '--only-missing', action='store_true', dest='only_missing',
+        '-M', '--only-missing', action='store_true',
         help='Show only missing dependencies.')
+    subparser.add_argument(
+        '-N', '--namespace', action='store_true',
+        help='Show fully qualified package names.')
 
     subparser.add_argument(
         'query_specs', nargs=argparse.REMAINDER,
@@ -76,6 +82,7 @@ def gray_hash(spec, length):
 def display_specs(specs, **kwargs):
     mode = kwargs.get('mode', 'short')
     hashes = kwargs.get('long', False)
+    namespace = kwargs.get('namespace', False)
 
     hlen = 7
     if kwargs.get('very_long', False):
@@ -97,7 +104,8 @@ def display_specs(specs, **kwargs):
         specs = index[(architecture,compiler)]
         specs.sort()
 
-        abbreviated = [s.format('$_$@$+', color=True) for s in specs]
+        nfmt = '.' if namespace else '_'
+        abbreviated = [s.format('$%s$@$+' % nfmt, color=True) for s in specs]
         if mode == 'paths':
             # Print one spec per line along with prefix path
             width = max(len(s) for s in abbreviated)
@@ -112,7 +120,7 @@ def display_specs(specs, **kwargs):
         elif mode == 'deps':
             for spec in specs:
                 print spec.tree(
-                    format='$_$@$+',
+                    format='$%s$@$+' % nfmt,
                     color=True,
                     indent=4,
                     prefix=(lambda s: gray_hash(s, hlen)) if hashes else None)
@@ -122,7 +130,7 @@ def display_specs(specs, **kwargs):
                 string = ""
                 if hashes:
                     string += gray_hash(s, hlen) + ' '
-                string += s.format('$-_$@$+', color=True)
+                string += s.format('$-%s$@$+' % nfmt, color=True)
 
                 return string
             colify(fmt(s) for s in specs)
@@ -137,7 +145,7 @@ def find(parser, args):
     # Filter out specs that don't exist.
     query_specs = spack.cmd.parse_specs(args.query_specs)
     query_specs, nonexisting = partition_list(
-        query_specs, lambda s: spack.db.exists(s.name))
+        query_specs, lambda s: spack.repo.exists(s.name))
 
     if nonexisting:
         msg = "No such package%s: " % ('s' if len(nonexisting) > 1 else '')
@@ -171,4 +179,5 @@ def find(parser, args):
         tty.msg("%d installed packages." % len(specs))
     display_specs(specs, mode=args.mode,
                   long=args.long,
-                  very_long=args.very_long)
+                  very_long=args.very_long,
+                  namespace=args.namespace)
diff --git a/lib/spack/spack/cmd/info.py b/lib/spack/spack/cmd/info.py
index 8040e23936..e7abe7f4a5 100644
--- a/lib/spack/spack/cmd/info.py
+++ b/lib/spack/spack/cmd/info.py
@@ -105,5 +105,5 @@ def print_text_info(pkg):
 
 
 def info(parser, args):
-    pkg = spack.db.get(args.name)
+    pkg = spack.repo.get(args.name)
     print_text_info(pkg)
diff --git a/lib/spack/spack/cmd/install.py b/lib/spack/spack/cmd/install.py
index 5ee7bc01b7..1fef750c80 100644
--- a/lib/spack/spack/cmd/install.py
+++ b/lib/spack/spack/cmd/install.py
@@ -70,7 +70,7 @@ def install(parser, args):
 
     specs = spack.cmd.parse_specs(args.packages, concretize=True)
     for spec in specs:
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         with spack.installed_db.write_transaction():
             package.do_install(
                 keep_prefix=args.keep_prefix,
diff --git a/lib/spack/spack/cmd/list.py b/lib/spack/spack/cmd/list.py
index b51d5b429a..7c50ccb9cd 100644
--- a/lib/spack/spack/cmd/list.py
+++ b/lib/spack/spack/cmd/list.py
@@ -43,7 +43,7 @@ def setup_parser(subparser):
 
 def list(parser, args):
     # Start with all package names.
-    pkgs = spack.db.all_package_names()
+    pkgs = spack.repo.all_package_names()
 
     # filter if a filter arg was provided
     if args.filter:
diff --git a/lib/spack/spack/cmd/location.py b/lib/spack/spack/cmd/location.py
index e805cc4012..39c225e9b2 100644
--- a/lib/spack/spack/cmd/location.py
+++ b/lib/spack/spack/cmd/location.py
@@ -72,7 +72,7 @@ def location(parser, args):
         print spack.prefix
 
     elif args.packages:
-        print spack.db.root
+        print spack.repo.root
 
     elif args.stages:
         print spack.stage_path
@@ -94,12 +94,12 @@ def location(parser, args):
 
             if args.package_dir:
                 # This one just needs the spec name.
-                print join_path(spack.db.root, spec.name)
+                print join_path(spack.repo.root, spec.name)
 
             else:
                 # These versions need concretized specs.
                 spec.concretize()
-                pkg = spack.db.get(spec)
+                pkg = spack.repo.get(spec)
 
                 if args.stage_dir:
                     print pkg.stage.path
diff --git a/lib/spack/spack/cmd/mirror.py b/lib/spack/spack/cmd/mirror.py
index 89d51bbe04..885483a840 100644
--- a/lib/spack/spack/cmd/mirror.py
+++ b/lib/spack/spack/cmd/mirror.py
@@ -36,6 +36,7 @@ import spack.config
 import spack.mirror
 from spack.spec import Spec
 from spack.error import SpackError
+from spack.util.spack_yaml import syaml_dict
 
 description = "Manage mirrors."
 
@@ -47,6 +48,7 @@ def setup_parser(subparser):
     sp = subparser.add_subparsers(
         metavar='SUBCOMMAND', dest='mirror_command')
 
+    # Create
     create_parser = sp.add_parser('create', help=mirror_create.__doc__)
     create_parser.add_argument('-d', '--directory', default=None,
                                help="Directory in which to create mirror.")
@@ -60,15 +62,29 @@ def setup_parser(subparser):
         '-o', '--one-version-per-spec', action='store_const', const=1, default=0,
         help="Only fetch one 'preferred' version per spec, not all known versions.")
 
+    scopes = spack.config.config_scopes
+
+    # Add
     add_parser = sp.add_parser('add', help=mirror_add.__doc__)
     add_parser.add_argument('name', help="Mnemonic name for mirror.")
     add_parser.add_argument(
         'url', help="URL of mirror directory created by 'spack mirror create'.")
+    add_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        help="Configuration scope to modify.")
 
-    remove_parser = sp.add_parser('remove', help=mirror_remove.__doc__)
+    # Remove
+    remove_parser = sp.add_parser('remove', aliases=['rm'], help=mirror_remove.__doc__)
     remove_parser.add_argument('name')
+    remove_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        help="Configuration scope to modify.")
 
+    # List
     list_parser = sp.add_parser('list', help=mirror_list.__doc__)
+    list_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        help="Configuration scope to read from.")
 
 
 def mirror_add(args):
@@ -77,31 +93,51 @@ def mirror_add(args):
     if url.startswith('/'):
         url = 'file://' + url
 
-    mirror_dict = { args.name : url }
-    spack.config.add_to_mirror_config({ args.name : url })
+    mirrors = spack.config.get_config('mirrors', scope=args.scope)
+    if not mirrors:
+        mirrors = syaml_dict()
+
+    for name, u in mirrors.items():
+        if name == args.name:
+            tty.die("Mirror with name %s already exists." % name)
+        if u == url:
+            tty.die("Mirror with url %s already exists." % url)
+        # should only be one item per mirror dict.
+
+    items = [(n,u) for n,u in mirrors.items()]
+    items.insert(0, (args.name, url))
+    mirrors = syaml_dict(items)
+    spack.config.update_config('mirrors', mirrors, scope=args.scope)
 
 
 def mirror_remove(args):
     """Remove a mirror by name."""
     name = args.name
 
-    rmd_something = spack.config.remove_from_config('mirrors', name)
-    if not rmd_something:
-        tty.die("No such mirror: %s" % name)
+    mirrors = spack.config.get_config('mirrors', scope=args.scope)
+    if not mirrors:
+        mirrors = syaml_dict()
+
+    if not name in mirrors:
+        tty.die("No mirror with name %s" % name)
+
+    old_value = mirrors.pop(name)
+    spack.config.update_config('mirrors', mirrors, scope=args.scope)
+    tty.msg("Removed mirror %s with url %s." % (name, old_value))
 
 
 def mirror_list(args):
     """Print out available mirrors to the console."""
-    sec_names = spack.config.get_mirror_config()
-    if not sec_names:
+    mirrors = spack.config.get_config('mirrors', scope=args.scope)
+    if not mirrors:
         tty.msg("No mirrors configured.")
         return
 
-    max_len = max(len(s) for s in sec_names)
+    max_len = max(len(n) for n in mirrors.keys())
     fmt = "%%-%ds%%s" % (max_len + 4)
 
-    for name, val in sec_names.iteritems():
-        print fmt % (name, val)
+    for name in mirrors:
+        print fmt % (name, mirrors[name])
 
 
 def _read_specs_from_file(filename):
@@ -130,7 +166,7 @@ def mirror_create(args):
 
     # If nothing is passed, use all packages.
     if not specs:
-        specs = [Spec(n) for n in spack.db.all_package_names()]
+        specs = [Spec(n) for n in spack.repo.all_package_names()]
         specs.sort(key=lambda s: s.format("$_$@").lower())
 
     if args.dependencies:
@@ -175,6 +211,7 @@ def mirror(parser, args):
     action = { 'create' : mirror_create,
                'add'    : mirror_add,
                'remove' : mirror_remove,
+               'rm'     : mirror_remove,
                'list'   : mirror_list }
 
     action[args.mirror_command](args)
diff --git a/lib/spack/spack/cmd/package-list.py b/lib/spack/spack/cmd/package-list.py
index eca9f918f1..5e37d5c16b 100644
--- a/lib/spack/spack/cmd/package-list.py
+++ b/lib/spack/spack/cmd/package-list.py
@@ -48,7 +48,7 @@ def rst_table(elts):
 
 def print_rst_package_list():
     """Print out information on all packages in restructured text."""
-    pkgs = sorted(spack.db.all_packages(), key=lambda s:s.name.lower())
+    pkgs = sorted(spack.repo.all_packages(), key=lambda s:s.name.lower())
 
     print ".. _package-list:"
     print
diff --git a/lib/spack/spack/cmd/patch.py b/lib/spack/spack/cmd/patch.py
index 8fc6f1383e..44fc8696db 100644
--- a/lib/spack/spack/cmd/patch.py
+++ b/lib/spack/spack/cmd/patch.py
@@ -47,5 +47,5 @@ def patch(parser, args):
 
     specs = spack.cmd.parse_specs(args.packages, concretize=True)
     for spec in specs:
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         package.do_patch()
diff --git a/lib/spack/spack/cmd/pkg.py b/lib/spack/spack/cmd/pkg.py
index 1ebc5ce3ee..448f762841 100644
--- a/lib/spack/spack/cmd/pkg.py
+++ b/lib/spack/spack/cmd/pkg.py
@@ -85,7 +85,7 @@ def list_packages(rev):
 
 def pkg_add(args):
     for pkg_name in args.packages:
-        filename = spack.db.filename_for_package_name(pkg_name)
+        filename = spack.repo.filename_for_package_name(pkg_name)
         if not os.path.isfile(filename):
             tty.die("No such package: %s.  Path does not exist:" % pkg_name, filename)
 
diff --git a/lib/spack/spack/cmd/providers.py b/lib/spack/spack/cmd/providers.py
index 0472f9bbe4..49d6ac192a 100644
--- a/lib/spack/spack/cmd/providers.py
+++ b/lib/spack/spack/cmd/providers.py
@@ -39,4 +39,4 @@ def setup_parser(subparser):
 
 def providers(parser, args):
     for spec in spack.cmd.parse_specs(args.vpkg_spec):
-        colify(sorted(spack.db.providers_for(spec)), indent=4)
+        colify(sorted(spack.repo.providers_for(spec)), indent=4)
diff --git a/lib/spack/spack/cmd/repo.py b/lib/spack/spack/cmd/repo.py
new file mode 100644
index 0000000000..34c755fb67
--- /dev/null
+++ b/lib/spack/spack/cmd/repo.py
@@ -0,0 +1,218 @@
+##############################################################################
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import os
+import re
+import shutil
+
+from external import argparse
+import llnl.util.tty as tty
+from llnl.util.filesystem import join_path, mkdirp
+
+import spack.spec
+import spack.config
+from spack.util.environment import get_path
+from spack.repository import *
+
+description = "Manage package source repositories."
+
+def setup_parser(subparser):
+    sp = subparser.add_subparsers(metavar='SUBCOMMAND', dest='repo_command')
+    scopes = spack.config.config_scopes
+
+    # Create
+    create_parser = sp.add_parser('create', help=repo_create.__doc__)
+    create_parser.add_argument(
+        'directory', help="Directory to create the repo in.")
+    create_parser.add_argument(
+        'namespace', help="Namespace to identify packages in the repository. "
+        "Defaults to the directory name.", nargs='?')
+
+    # List
+    list_parser = sp.add_parser('list', help=repo_list.__doc__)
+    list_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_list_scope,
+        help="Configuration scope to read from.")
+
+    # Add
+    add_parser = sp.add_parser('add', help=repo_add.__doc__)
+    add_parser.add_argument('path', help="Path to a Spack package repository directory.")
+    add_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        help="Configuration scope to modify.")
+
+    # Remove
+    remove_parser = sp.add_parser('remove', help=repo_remove.__doc__, aliases=['rm'])
+    remove_parser.add_argument(
+        'path_or_namespace',
+        help="Path or namespace of a Spack package repository.")
+    remove_parser.add_argument(
+        '--scope', choices=scopes, default=spack.cmd.default_modify_scope,
+        help="Configuration scope to modify.")
+
+
+def repo_create(args):
+    """Create a new package repository."""
+    root = canonicalize_path(args.directory)
+    namespace = args.namespace
+
+    if not args.namespace:
+        namespace = os.path.basename(root)
+
+    if not re.match(r'\w[\.\w-]*', namespace):
+        tty.die("'%s' is not a valid namespace." % namespace)
+
+    existed = False
+    if os.path.exists(root):
+        if os.path.isfile(root):
+            tty.die('File %s already exists and is not a directory' % root)
+        elif os.path.isdir(root):
+            if not os.access(root, os.R_OK | os.W_OK):
+                tty.die('Cannot create new repo in %s: cannot access directory.' % root)
+            if os.listdir(root):
+                tty.die('Cannot create new repo in %s: directory is not empty.' % root)
+        existed = True
+
+    full_path = os.path.realpath(root)
+    parent = os.path.dirname(full_path)
+    if not os.access(parent, os.R_OK | os.W_OK):
+        tty.die("Cannot create repository in %s: can't access parent!" % root)
+
+    try:
+        config_path = os.path.join(root, repo_config_name)
+        packages_path = os.path.join(root, packages_dir_name)
+
+        mkdirp(packages_path)
+        with open(config_path, 'w') as config:
+            config.write("repo:\n")
+            config.write("  namespace: '%s'\n" % namespace)
+
+    except (IOError, OSError) as e:
+        tty.die('Failed to create new repository in %s.' % root,
+                "Caused by %s: %s" % (type(e), e))
+
+        # try to clean up.
+        if existed:
+            shutil.rmtree(config_path, ignore_errors=True)
+            shutil.rmtree(packages_path, ignore_errors=True)
+        else:
+            shutil.rmtree(root, ignore_errors=True)
+
+    tty.msg("Created repo with namespace '%s'." % namespace)
+    tty.msg("To register it with spack, run this command:",
+            'spack repo add %s' % full_path)
+
+
+def repo_add(args):
+    """Add a package source to Spack's configuration."""
+    path = args.path
+
+    # real_path is absolute and handles substitution.
+    canon_path = canonicalize_path(path)
+
+    # check if the path exists
+    if not os.path.exists(canon_path):
+        tty.die("No such file or directory: '%s'." % path)
+
+    # Make sure the path is a directory.
+    if not os.path.isdir(canon_path):
+        tty.die("Not a Spack repository: '%s'." % path)
+
+    # Make sure it's actually a spack repository by constructing it.
+    repo = Repo(canon_path)
+
+    # If that succeeds, finally add it to the configuration.
+    repos = spack.config.get_config('repos', args.scope)
+    if not repos: repos = []
+
+    if repo.root in repos or path in repos:
+        tty.die("Repository is already registered with Spack: '%s'" % path)
+
+    repos.insert(0, canon_path)
+    spack.config.update_config('repos', repos, args.scope)
+    tty.msg("Created repo with namespace '%s'." % repo.namespace)
+
+
+def repo_remove(args):
+    """Remove a repository from Spack's configuration."""
+    repos = spack.config.get_config('repos', args.scope)
+    path_or_namespace = args.path_or_namespace
+
+    # If the argument is a path, remove that repository from config.
+    canon_path = canonicalize_path(path_or_namespace)
+    for repo_path in repos:
+        repo_canon_path = canonicalize_path(repo_path)
+        if canon_path == repo_canon_path:
+            repos.remove(repo_path)
+            spack.config.update_config('repos', repos, args.scope)
+            tty.msg("Removed repository '%s'." % repo_path)
+            return
+
+    # If it is a namespace, remove corresponding repo
+    for path in repos:
+        try:
+            repo = Repo(path)
+            if repo.namespace == path_or_namespace:
+                repos.remove(path)
+                spack.config.update_config('repos', repos, args.scope)
+                tty.msg("Removed repository '%s' with namespace %s."
+                        % (repo.root, repo.namespace))
+                return
+        except RepoError as e:
+            continue
+
+    tty.die("No repository with path or namespace: '%s'"
+            % path_or_namespace)
+
+
+def repo_list(args):
+    """Show registered repositories and their namespaces."""
+    roots = spack.config.get_config('repos', args.scope)
+    repos = []
+    for r in roots:
+        try:
+            repos.append(Repo(r))
+        except RepoError as e:
+            continue
+
+    msg = "%d package repositor" % len(repos)
+    msg += "y." if len(repos) == 1 else "ies."
+    tty.msg(msg)
+
+    if not repos:
+        return
+
+    max_ns_len = max(len(r.namespace) for r in repos)
+    for repo in repos:
+        fmt = "%%-%ds%%s" % (max_ns_len + 4)
+        print fmt % (repo.namespace, repo.root)
+
+
+def repo(parser, args):
+    action = { 'create' : repo_create,
+               'list'   : repo_list,
+               'add'    : repo_add,
+               'remove' : repo_remove,
+               'rm'     : repo_remove}
+    action[args.repo_command](args)
diff --git a/lib/spack/spack/cmd/restage.py b/lib/spack/spack/cmd/restage.py
index 703ae30a04..540c2ef2a5 100644
--- a/lib/spack/spack/cmd/restage.py
+++ b/lib/spack/spack/cmd/restage.py
@@ -42,5 +42,5 @@ def restage(parser, args):
 
     specs = spack.cmd.parse_specs(args.packages, concretize=True)
     for spec in specs:
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         package.do_restage()
diff --git a/lib/spack/spack/cmd/stage.py b/lib/spack/spack/cmd/stage.py
index 7638cf31c4..5786780efb 100644
--- a/lib/spack/spack/cmd/stage.py
+++ b/lib/spack/spack/cmd/stage.py
@@ -49,5 +49,5 @@ def stage(parser, args):
 
     specs = spack.cmd.parse_specs(args.specs, concretize=True)
     for spec in specs:
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         package.do_stage()
diff --git a/lib/spack/spack/cmd/test-install.py b/lib/spack/spack/cmd/test-install.py
index e37554155f..74017f59fb 100644
--- a/lib/spack/spack/cmd/test-install.py
+++ b/lib/spack/spack/cmd/test-install.py
@@ -115,7 +115,7 @@ def fetch_log(path):
 
 def failed_dependencies(spec):
     return set(childSpec for childSpec in spec.dependencies.itervalues() if not 
-        spack.db.get(childSpec).installed)
+        spack.repo.get(childSpec).installed)
 
 
 def create_test_output(topSpec, newInstalls, output, getLogFunc=fetch_log):
@@ -126,7 +126,7 @@ def create_test_output(topSpec, newInstalls, output, getLogFunc=fetch_log):
             continue
 
         failedDeps = failed_dependencies(spec)
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         if failedDeps:
             result = TestResult.SKIPPED
             dep = iter(failedDeps).next()
@@ -171,7 +171,7 @@ def test_install(parser, args):
     
     newInstalls = set()
     for spec in topSpec.traverse():
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         if not package.installed:
             newInstalls.add(spec)
     
@@ -188,7 +188,7 @@ def test_install(parser, args):
         # Calling do_install for the top-level package would be sufficient but
         # this attempts to keep going if any package fails (other packages which
         # are not dependents may succeed)
-        package = spack.db.get(spec)
+        package = spack.repo.get(spec)
         if (not failed_dependencies(spec)) and (not package.installed):
             try:
                 package.do_install(
diff --git a/lib/spack/spack/cmd/uninstall.py b/lib/spack/spack/cmd/uninstall.py
index 03873bb5f8..d01aa2136b 100644
--- a/lib/spack/spack/cmd/uninstall.py
+++ b/lib/spack/spack/cmd/uninstall.py
@@ -30,7 +30,7 @@ from llnl.util.tty.colify import colify
 
 import spack
 import spack.cmd
-import spack.packages
+import spack.repository
 from spack.cmd.find import display_specs
 from spack.package import PackageStillNeededError
 
@@ -79,10 +79,9 @@ def uninstall(parser, args):
                 try:
                     # should work if package is known to spack
                     pkgs.append(s.package)
-
-                except spack.packages.UnknownPackageError, e:
-                    # The package.py file has gone away -- but still want to
-                    # uninstall.
+                except spack.repository.UnknownPackageError, e:
+                    # The package.py file has gone away -- but still
+                    # want to uninstall.
                     spack.Package(s).do_uninstall(force=True)
 
         # Sort packages to be uninstalled by the number of installed dependents
diff --git a/lib/spack/spack/cmd/urls.py b/lib/spack/spack/cmd/urls.py
index a544b6153b..ebab65f7d1 100644
--- a/lib/spack/spack/cmd/urls.py
+++ b/lib/spack/spack/cmd/urls.py
@@ -41,7 +41,7 @@ def setup_parser(subparser):
 
 def urls(parser, args):
     urls = set()
-    for pkg in spack.db.all_packages():
+    for pkg in spack.repo.all_packages():
         url = getattr(pkg.__class__, 'url', None)
         if url:
             urls.add(url)
diff --git a/lib/spack/spack/cmd/versions.py b/lib/spack/spack/cmd/versions.py
index 494f13d36d..bba75dae96 100644
--- a/lib/spack/spack/cmd/versions.py
+++ b/lib/spack/spack/cmd/versions.py
@@ -34,7 +34,7 @@ def setup_parser(subparser):
 
 
 def versions(parser, args):
-    pkg = spack.db.get(args.package)
+    pkg = spack.repo.get(args.package)
 
     safe_versions = pkg.versions
     fetched_versions = pkg.fetch_remote_versions()
diff --git a/lib/spack/spack/compilers/__init__.py b/lib/spack/spack/compilers/__init__.py
index 66e608cf79..facc9c338b 100644
--- a/lib/spack/spack/compilers/__init__.py
+++ b/lib/spack/spack/compilers/__init__.py
@@ -27,6 +27,7 @@ system and configuring Spack to use multiple compilers.
 """
 import imp
 import os
+import platform
 
 from llnl.util.lang import memoized, list_modules
 from llnl.util.filesystem import join_path
@@ -35,6 +36,7 @@ import spack
 import spack.error
 import spack.spec
 import spack.config
+import spack.architecture
 
 from spack.util.multiproc import parmap
 from spack.compiler import Compiler
@@ -45,50 +47,128 @@ from spack.util.environment import get_path
 _imported_compilers_module = 'spack.compilers'
 _required_instance_vars = ['cc', 'cxx', 'f77', 'fc']
 
-_default_order = ['gcc', 'intel', 'pgi', 'clang', 'xlc']
+# TODO: customize order in config file
+if platform.system() == 'Darwin':
+    _default_order = ['clang', 'gcc', 'intel']
+else:
+    _default_order = ['gcc', 'intel', 'pgi', 'clang', 'xlc']
+
 
 def _auto_compiler_spec(function):
-    def converter(cspec_like):
+    def converter(cspec_like, *args, **kwargs):
         if not isinstance(cspec_like, spack.spec.CompilerSpec):
             cspec_like = spack.spec.CompilerSpec(cspec_like)
-        return function(cspec_like)
+        return function(cspec_like, *args, **kwargs)
     return converter
 
 
-def _get_config():
-    """Get a Spack config, but make sure it has compiler configuration
-       first."""
+def _to_dict(compiler):
+    """Return a dict version of compiler suitable to insert in YAML."""
+    return {
+        str(compiler.spec) : dict(
+            (attr, getattr(compiler, attr, None))
+            for attr in _required_instance_vars)
+    }
+
+
+def get_compiler_config(arch=None, scope=None):
+    """Return the compiler configuration for the specified architecture.
+    """
     # If any configuration file has compilers, just stick with the
     # ones already configured.
-    config = spack.config.get_compilers_config()
-    existing = [spack.spec.CompilerSpec(s)
-                for s in config]
-    if existing:
-        return config
+    config = spack.config.get_config('compilers', scope=scope)
+
+    my_arch = spack.architecture.sys_type()
+    if arch is None:
+        arch = my_arch
+
+    if arch in config:
+        return config[arch]
+
+    # Only for the current arch in *highest* scope: automatically try to
+    # find compilers if none are configured yet.
+    if arch == my_arch and scope == 'user':
+        config[arch] = {}
+        compilers = find_compilers(*get_path('PATH'))
+        for compiler in compilers:
+            config[arch].update(_to_dict(compiler))
+        spack.config.update_config('compilers', config, scope=scope)
+        return config[arch]
+
+    return {}
+
+
+def add_compilers_to_config(compilers, arch=None, scope=None):
+    """Add compilers to the config for the specified architecture.
+
+    Arguments:
+      - compilers: a list of Compiler objects.
+      - arch:      arch to add compilers for.
+      - scope:     configuration scope to modify.
+    """
+    if arch is None:
+        arch = spack.architecture.sys_type()
+
+    compiler_config = get_compiler_config(arch, scope)
+    for compiler in compilers:
+        compiler_config[str(compiler.spec)] = dict(
+            (c, getattr(compiler, c, "None"))
+            for c in _required_instance_vars)
+
+    update = { arch : compiler_config }
+    spack.config.update_config('compilers', update, scope)
+
+
+@_auto_compiler_spec
+def remove_compiler_from_config(compiler_spec, arch=None, scope=None):
+    """Remove compilers from the config, by spec.
+
+    Arguments:
+      - compiler_specs: a list of CompilerSpec objects.
+      - arch:           arch to add compilers for.
+      - scope:          configuration scope to modify.
+    """
+    if arch is None:
+        arch = spack.architecture.sys_type()
 
-    compilers = find_compilers(*get_path('PATH'))
-    add_compilers_to_config('user', *compilers)
+    compiler_config = get_compiler_config(arch, scope)
+    del compiler_config[str(compiler_spec)]
+    update = { arch : compiler_config }
 
-    # After writing compilers to the user config, return a full config
-    # from all files.
-    return spack.config.get_compilers_config()
+    spack.config.update_config('compilers', update, scope)
+
+
+def all_compilers_config(arch=None, scope=None):
+    """Return a set of specs for all the compiler versions currently
+       available to build with.  These are instances of CompilerSpec.
+    """
+    # Get compilers for this architecture.
+    arch_config = get_compiler_config(arch, scope)
+
+    # Merge 'all' compilers with arch-specific ones.
+    # Arch-specific compilers have higher precedence.
+    merged_config = get_compiler_config('all', scope=scope)
+    merged_config = spack.config._merge_yaml(merged_config, arch_config)
+
+    return merged_config
+
+
+def all_compilers(arch=None, scope=None):
+    # Return compiler specs from the merged config.
+    return [spack.spec.CompilerSpec(s)
+            for s in all_compilers_config(arch, scope)]
 
 
-_cached_default_compiler = None
 def default_compiler():
-    global _cached_default_compiler
-    if _cached_default_compiler:
-        return _cached_default_compiler
     versions = []
-    for name in _default_order:  # TODO: customize order.
+    for name in _default_order:
         versions = find(name)
-        if versions: break
-
-    if not versions:
+        if versions:
+            break
+    else:
         raise NoCompilersError()
 
-    _cached_default_compiler = sorted(versions)[-1]
-    return _cached_default_compiler
+    return sorted(versions)[-1]
 
 
 def find_compilers(*path):
@@ -123,20 +203,6 @@ def find_compilers(*path):
     return clist
 
 
-def add_compilers_to_config(scope, *compilers):
-    compiler_config_tree = {}
-    for compiler in compilers:
-        compiler_entry = {}
-        for c in _required_instance_vars:
-            val = getattr(compiler, c)
-            if not val:
-                val = "None"
-            compiler_entry[c] = val
-        compiler_config_tree[str(compiler.spec)] = compiler_entry
-    spack.config.add_to_compiler_config(compiler_config_tree, scope)
-
-
-
 def supported_compilers():
     """Return a set of names of compilers supported by Spack.
 
@@ -152,27 +218,19 @@ def supported(compiler_spec):
     return compiler_spec.name in supported_compilers()
 
 
-def all_compilers():
-    """Return a set of specs for all the compiler versions currently
-       available to build with.  These are instances of CompilerSpec.
-    """
-    configuration = _get_config()
-    return [spack.spec.CompilerSpec(s) for s in configuration]
-
-
 @_auto_compiler_spec
-def find(compiler_spec):
+def find(compiler_spec, arch=None, scope=None):
     """Return specs of available compilers that match the supplied
        compiler spec.  Return an list if nothing found."""
-    return [c for c in all_compilers() if c.satisfies(compiler_spec)]
+    return [c for c in all_compilers(arch, scope) if c.satisfies(compiler_spec)]
 
 
 @_auto_compiler_spec
-def compilers_for_spec(compiler_spec):
+def compilers_for_spec(compiler_spec, arch=None, scope=None):
     """This gets all compilers that satisfy the supplied CompilerSpec.
        Returns an empty list if none are found.
     """
-    config = _get_config()
+    config = all_compilers_config(arch, scope)
 
     def get_compiler(cspec):
         items = config[str(cspec)]
@@ -191,7 +249,7 @@ def compilers_for_spec(compiler_spec):
 
         return cls(cspec, *compiler_paths)
 
-    matches = find(compiler_spec)
+    matches = find(compiler_spec, arch, scope)
     return [get_compiler(cspec) for cspec in matches]
 
 
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index c127f6a28f..193b311434 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -1,5 +1,5 @@
 ##############################################################################
-# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
 # Produced at the Lawrence Livermore National Laboratory.
 #
 # This file is part of Spack.
@@ -45,11 +45,11 @@ several configuration files, such as compilers.yaml or mirrors.yaml.
 Configuration file format
 ===============================
 
-Configuration files are formatted using YAML syntax.
-This format is implemented by Python's
-yaml class, and it's easy to read and versatile.
+Configuration files are formatted using YAML syntax.  This format is
+implemented by libyaml (included with Spack as an external module),
+and it's easy to read and versatile.
 
-The config files are structured as trees, like this ``compiler`` section::
+Config files are structured as trees, like this ``compiler`` section::
 
      compilers:
        chaos_5_x86_64_ib:
@@ -67,274 +67,475 @@ In this example, entries like ''compilers'' and ''xlc@12.1'' are used to
 categorize entries beneath them in the tree.  At the root of the tree,
 entries like ''cc'' and ''cxx'' are specified as name/value pairs.
 
-Spack returns these trees as nested dicts.  The dict for the above example
-would looks like:
-
-  { 'compilers' :
-      { 'chaos_5_x86_64_ib' :
-         { 'gcc@4.4.7' :
-             { 'cc' : '/usr/bin/gcc',
-               'cxx' : '/usr/bin/g++'
-               'f77' : '/usr/bin/gfortran'
-               'fc' : '/usr/bin/gfortran' }
-         }
-     { 'bgqos_0' :
-         { 'cc' : '/usr/local/bin/mpixlc' }
-     }
-  }
-
-Some routines, like get_mirrors_config and get_compilers_config may strip
-off the top-levels of the tree and return subtrees.
+``config.get_config()`` returns these trees as nested dicts, but it
+strips the first level off.  So, ``config.get_config('compilers')``
+would return something like this for the above example:
+
+   { 'chaos_5_x86_64_ib' :
+       { 'gcc@4.4.7' :
+           { 'cc' : '/usr/bin/gcc',
+             'cxx' : '/usr/bin/g++'
+             'f77' : '/usr/bin/gfortran'
+             'fc' : '/usr/bin/gfortran' }
+           }
+       { 'bgqos_0' :
+          { 'cc' : '/usr/local/bin/mpixlc' } }
+
+Likewise, the ``mirrors.yaml`` file's first line must be ``mirrors:``,
+but ``get_config()`` strips that off too.
+
+Precedence
+===============================
+
+``config.py`` routines attempt to recursively merge configuration
+across scopes.  So if there are ``compilers.py`` files in both the
+site scope and the user scope, ``get_config('compilers')`` will return
+merged dictionaries of *all* the compilers available.  If a user
+compiler conflicts with a site compiler, Spack will overwrite the site
+configuration wtih the user configuration.  If both the user and site
+``mirrors.yaml`` files contain lists of mirrors, then ``get_config()``
+will return a concatenated list of mirrors, with the user config items
+first.
+
+Sometimes, it is useful to *completely* override a site setting with a
+user one.  To accomplish this, you can use *two* colons at the end of
+a key in a configuration file.  For example, this:
+
+     compilers::
+       chaos_5_x86_64_ib:
+          gcc@4.4.7:
+            cc: /usr/bin/gcc
+            cxx: /usr/bin/g++
+            f77: /usr/bin/gfortran
+            fc: /usr/bin/gfortran
+       bgqos_0:
+          xlc@12.1:
+            cc: /usr/local/bin/mpixlc
+            ...
+
+Will make Spack take compilers *only* from the user configuration, and
+the site configuration will be ignored.
+
 """
 import os
-import exceptions
+import re
 import sys
-
-from ordereddict_backport import OrderedDict
-from llnl.util.lang import memoized
-import spack.error
-
+import copy
+import jsonschema
+from jsonschema import Draft4Validator, validators
 import yaml
 from yaml.error import MarkedYAMLError
+from ordereddict_backport import OrderedDict
+
 import llnl.util.tty as tty
 from llnl.util.filesystem import mkdirp
 
-_config_sections = {}
-class _ConfigCategory:
-    name = None
-    filename = None
-    merge = True
-    def __init__(self, n, f, m):
-        self.name = n
-        self.filename = f
-        self.merge = m
-        self.files_read_from = []
-        self.result_dict = {}
-        _config_sections[n] = self
-
-_ConfigCategory('compilers', 'compilers.yaml', True)
-_ConfigCategory('mirrors', 'mirrors.yaml', True)
-_ConfigCategory('view', 'views.yaml', True)
-_ConfigCategory('order', 'orders.yaml', True)
-
-"""Names of scopes and their corresponding configuration files."""
-config_scopes = [('site', os.path.join(spack.etc_path, 'spack')),
-                 ('user', os.path.expanduser('~/.spack'))]
-
-_compiler_by_arch = {}
-_read_config_file_result = {}
-def _read_config_file(filename):
-    """Read a given YAML configuration file"""
-    global _read_config_file_result
-    if filename in _read_config_file_result:
-        return _read_config_file_result[filename]
+import spack
+from spack.error import SpackError
+
+# Hacked yaml for configuration files preserves line numbers.
+import spack.util.spack_yaml as syaml
+
+
+"""Dict from section names -> schema for that section."""
+section_schemas = {
+    'compilers': {
+        '$schema': 'http://json-schema.org/schema#',
+        'title': 'Spack compiler configuration file schema',
+        'type': 'object',
+        'additionalProperties': False,
+        'patternProperties': {
+            'compilers:?': { # optional colon for overriding site config.
+                'type': 'object',
+                'default': {},
+                'additionalProperties': False,
+                'patternProperties': {
+                    r'\w[\w-]*': {           # architecture
+                        'type': 'object',
+                        'additionalProperties': False,
+                        'patternProperties': {
+                            r'\w[\w-]*@\w[\w-]*': {   # compiler spec
+                                'type': 'object',
+                                'additionalProperties': False,
+                                'required': ['cc', 'cxx', 'f77', 'fc'],
+                                'properties': {
+                                    'cc':  { 'anyOf': [ {'type' : 'string' },
+                                                        {'type' : 'null' }]},
+                                    'cxx': { 'anyOf': [ {'type' : 'string' },
+                                                        {'type' : 'null' }]},
+                                    'f77': { 'anyOf': [ {'type' : 'string' },
+                                                        {'type' : 'null' }]},
+                                    'fc':  { 'anyOf': [ {'type' : 'string' },
+                                                        {'type' : 'null' }]},
+                                },},},},},},},},
+
+    'mirrors': {
+        '$schema': 'http://json-schema.org/schema#',
+        'title': 'Spack mirror configuration file schema',
+        'type': 'object',
+        'additionalProperties': False,
+        'patternProperties': {
+            r'mirrors:?': {
+                'type': 'object',
+                'default': {},
+                'additionalProperties': False,
+                'patternProperties': {
+                    r'\w[\w-]*': {
+                        'type': 'string'},},},},},
+
+    'repos': {
+        '$schema': 'http://json-schema.org/schema#',
+        'title': 'Spack repository configuration file schema',
+        'type': 'object',
+        'additionalProperties': False,
+        'patternProperties': {
+            r'repos:?': {
+                'type': 'array',
+                'default': [],
+                'items': {
+                    'type': 'string'},},},},
+}
+
+"""OrderedDict of config scopes keyed by name.
+   Later scopes will override earlier scopes.
+"""
+config_scopes = OrderedDict()
+
+
+def validate_section_name(section):
+    """Raise a ValueError if the section is not a valid section."""
+    if section not in section_schemas:
+        raise ValueError("Invalid config section: '%s'.  Options are %s."
+                         % (section, section_schemas))
+
+
+def extend_with_default(validator_class):
+    """Add support for the 'default' attribute for properties and patternProperties.
+
+       jsonschema does not handle this out of the box -- it only
+       validates.  This allows us to set default values for configs
+       where certain fields are `None` b/c they're deleted or
+       commented out.
+
+    """
+    validate_properties = validator_class.VALIDATORS["properties"]
+    validate_pattern_properties = validator_class.VALIDATORS["patternProperties"]
+
+    def set_defaults(validator, properties, instance, schema):
+        for property, subschema in properties.iteritems():
+            if "default" in subschema:
+                instance.setdefault(property, subschema["default"])
+        for err in validate_properties(validator, properties, instance, schema):
+            yield err
+
+    def set_pp_defaults(validator, properties, instance, schema):
+        for property, subschema in properties.iteritems():
+            if "default" in subschema:
+                if isinstance(instance, dict):
+                    for key, val in instance.iteritems():
+                        if re.match(property, key) and val is None:
+                            instance[key] = subschema["default"]
+
+        for err in validate_pattern_properties(validator, properties, instance, schema):
+            yield err
+
+    return validators.extend(validator_class, {
+        "properties" : set_defaults,
+        "patternProperties" : set_pp_defaults
+    })
+
+
+DefaultSettingValidator = extend_with_default(Draft4Validator)
+
+def validate_section(data, schema):
+    """Validate data read in from a Spack YAML file.
+
+    This leverages the line information (start_mark, end_mark) stored
+    on Spack YAML structures.
+
+    """
+    try:
+        DefaultSettingValidator(schema).validate(data)
+    except jsonschema.ValidationError as e:
+        raise ConfigFormatError(e, data)
+
+
+class ConfigScope(object):
+    """This class represents a configuration scope.
+
+       A scope is one directory containing named configuration files.
+       Each file is a config "section" (e.g., mirrors, compilers, etc).
+    """
+
+    def __init__(self, name, path):
+        self.name = name           # scope name.
+        self.path = path           # path to directory containing configs.
+        self.sections = {}         # sections read from config files.
+
+        # Register in a dict of all ConfigScopes
+        # TODO: make this cleaner.  Mocking up for testing is brittle.
+        global config_scopes
+        config_scopes[name] = self
+
+    def get_section_filename(self, section):
+        validate_section_name(section)
+        return os.path.join(self.path, "%s.yaml" % section)
+
+
+    def get_section(self, section):
+        if not section in self.sections:
+            path   = self.get_section_filename(section)
+            schema = section_schemas[section]
+            data   = _read_config_file(path, schema)
+            self.sections[section] = data
+        return self.sections[section]
+
+
+    def write_section(self, section):
+        filename = self.get_section_filename(section)
+        data = self.get_section(section)
+        try:
+            mkdirp(self.path)
+            with open(filename, 'w') as f:
+                validate_section(data, section_schemas[section])
+                syaml.dump(data, stream=f, default_flow_style=False)
+        except jsonschema.ValidationError as e:
+            raise ConfigSanityError(e, data)
+        except (yaml.YAMLError, IOError) as e:
+            raise ConfigFileError("Error writing to config file: '%s'" % str(e))
+
+
+    def clear(self):
+        """Empty cached config information."""
+        self.sections = {}
+
+
+ConfigScope('site', os.path.join(spack.etc_path, 'spack')),
+ConfigScope('user', os.path.expanduser('~/.spack'))
+
+
+def highest_precedence_scope():
+    """Get the scope with highest precedence (prefs will override others)."""
+    return config_scopes.values()[-1]
+
+
+def validate_scope(scope):
+    """Ensure that scope is valid, and return a valid scope if it is None.
+
+       This should be used by routines in ``config.py`` to validate
+       scope name arguments, and to determine a default scope where no
+       scope is specified.
+
+    """
+    if scope is None:
+        # default to the scope with highest precedence.
+        return highest_precedence_scope()
+
+    elif scope in config_scopes:
+        return config_scopes[scope]
+
+    else:
+        raise ValueError("Invalid config scope: '%s'.  Must be one of %s."
+                         % (scope, config_scopes.keys()))
+
+
+def _read_config_file(filename, schema):
+    """Read a YAML configuration file."""
+    # Ignore nonexisting files.
+    if not os.path.exists(filename):
+        return None
+
+    elif not os.path.isfile(filename):
+        raise ConfigFileError(
+            "Invlaid configuration. %s exists but is not a file." % filename)
+
+    elif not os.access(filename, os.R_OK):
+        raise ConfigFileError("Config file is not readable: %s." % filename)
 
     try:
+        tty.debug("Reading config file %s" % filename)
         with open(filename) as f:
-            ydict = yaml.load(f)
+            data = syaml.load(f)
+
+        validate_section(data, schema)
+
+        return data
+
     except MarkedYAMLError, e:
-        tty.die("Error parsing yaml%s: %s" % (str(e.context_mark), e.problem))
-    except exceptions.IOError, e:
-        _read_config_file_result[filename] = None
-        return None
-    _read_config_file_result[filename] = ydict
-    return ydict
+        raise ConfigFileError(
+            "Error parsing yaml%s: %s" % (str(e.context_mark), e.problem))
+
+    except IOError, e:
+        raise ConfigFileError(
+            "Error reading configuration file %s: %s" % (filename, str(e)))
 
 
 def clear_config_caches():
     """Clears the caches for configuration files, which will cause them
        to be re-read upon the next request"""
-    for key,s in _config_sections.iteritems():
-        s.files_read_from = []
-        s.result_dict = {}
-    spack.config._read_config_file_result = {}
-    spack.config._compiler_by_arch = {}
-    spack.compilers._cached_default_compiler = None
-
-
-def _merge_dicts(d1, d2):
-    """Recursively merges two configuration trees, with entries
-       in d2 taking precedence over d1"""
-    if not d1:
-        return d2.copy()
-    if not d2:
-        return d1
-
-    for key2, val2 in d2.iteritems():
-        if not key2 in d1:
-            d1[key2] = val2
-            continue
-        val1 = d1[key2]
-        if isinstance(val1, dict) and isinstance(val2, dict):
-            d1[key2] = _merge_dicts(val1, val2)
-            continue
-        if isinstance(val1, list) and isinstance(val2, list):
-            val1.extend(val2)
-            seen = set()
-            d1[key2] = [ x for x in val1 if not (x in seen or seen.add(x)) ]
-            continue
-        d1[key2] = val2
-    return d1
-
-
-def get_config(category_name):
-    """Get the confguration tree for the names category.  Strips off the
-       top-level category entry from the dict"""
-    global config_scopes
-    category = _config_sections[category_name]
-    if category.result_dict:
-        return category.result_dict
-
-    category.result_dict = {}
-    for scope, scope_path in config_scopes:
-        path = os.path.join(scope_path, category.filename)
-        result = _read_config_file(path)
-        if not result:
-            continue
-        if not category_name in result:
-            continue
-        category.files_read_from.insert(0, path)
-        result = result[category_name]
-        if category.merge:
-            category.result_dict = _merge_dicts(category.result_dict, result)
-        else:
-            category.result_dict = result
-    return category.result_dict
-
-
-def get_compilers_config(arch=None):
-    """Get the compiler configuration from config files for the given
-       architecture.  Strips off the architecture component of the
-       configuration"""
-    global _compiler_by_arch
-    if not arch:
-        arch = spack.architecture.sys_type()
-    if arch in _compiler_by_arch:
-        return _compiler_by_arch[arch]
-
-    cc_config = get_config('compilers')
-    if arch in cc_config and 'all' in cc_config:
-        arch_compiler = dict(cc_config[arch])
-        _compiler_by_arch[arch] = _merge_dict(arch_compiler, cc_config['all'])
-    elif arch in cc_config:
-        _compiler_by_arch[arch] = cc_config[arch]
-    elif 'all' in cc_config:
-        _compiler_by_arch[arch] = cc_config['all']
+    for scope in config_scopes.values():
+        scope.clear()
+
+
+def _merge_yaml(dest, source):
+    """Merges source into dest; entries in source take precedence over dest.
+
+    This routine may modify dest and should be assigned to dest, in
+    case dest was None to begin with, e.g.:
+
+       dest = _merge_yaml(dest, source)
+
+    Config file authors can optionally end any attribute in a dict
+    with `::` instead of `:`, and the key will override that of the
+    parent instead of merging.
+
+    """
+    def they_are(t):
+        return isinstance(dest, t) and isinstance(source, t)
+
+    # If both are None, handle specially and return None.
+    if source is None and dest is None:
+        return None
+
+    # If source is None, overwrite with source.
+    elif source is None:
+        return None
+
+    # Source list is prepended (for precedence)
+    if they_are(list):
+        seen = set(source)
+        dest[:] = source + [x for x in dest if x not in seen]
+        return dest
+
+    # Source dict is merged into dest.
+    elif they_are(dict):
+        for sk, sv in source.iteritems():
+            if not sk in dest:
+                dest[sk] = copy.copy(sv)
+            else:
+                dest[sk] = _merge_yaml(dest[sk], source[sk])
+        return dest
+
+    # In any other case, overwrite with a copy of the source value.
     else:
-        _compiler_by_arch[arch] = {}
-    return _compiler_by_arch[arch]
-
-
-def get_mirror_config():
-    """Get the mirror configuration from config files"""
-    return get_config('mirrors')
-
-
-def get_config_scope_dirname(scope):
-    """For a scope return the config directory"""
-    global config_scopes
-    for s,p in config_scopes:
-        if s == scope:
-            return p
-    tty.die("Unknown scope %s.  Valid options are %s" %
-            (scope, ", ".join([s for s,p in config_scopes])))
-
-
-def get_config_scope_filename(scope, category_name):
-    """For some scope and category, get the name of the configuration file"""
-    if not category_name in _config_sections:
-        tty.die("Unknown config category %s.  Valid options are: %s" %
-                (category_name, ", ".join([s for s in _config_sections])))
-    return os.path.join(get_config_scope_dirname(scope), _config_sections[category_name].filename)
-
-
-def add_to_config(category_name, addition_dict, scope=None):
-    """Merge a new dict into a configuration tree and write the new
-       configuration to disk"""
-    global _read_config_file_result
-    get_config(category_name)
-    category = _config_sections[category_name]
-
-    #If scope is specified, use it.  Otherwise use the last config scope that
-    #we successfully parsed data from.
-    file = None
-    path = None
-    if not scope and not category.files_read_from:
-        scope = 'user'
-    if scope:
-        try:
-            dir = get_config_scope_dirname(scope)
-            if not os.path.exists(dir):
-                mkdirp(dir)
-            path = os.path.join(dir, category.filename)
-            file = open(path, 'w')
-        except exceptions.IOError, e:
-            pass
+        return copy.copy(source)
+
+
+def get_config(section, scope=None):
+    """Get configuration settings for a section.
+
+       Strips off the top-level section name from the YAML dict.
+    """
+    validate_section_name(section)
+    merged_section = syaml.syaml_dict()
+
+    if scope is None:
+        scopes = config_scopes.values()
     else:
-        for p in category.files_read_from:
-            try:
-                file = open(p, 'w')
-            except exceptions.IOError, e:
-                pass
-            if file:
-                path = p
-                break;
-    if not file:
-        tty.die('Unable to write to config file %s' % path)
-
-    #Merge the new information into the existing file info, then write to disk
-    new_dict = _read_config_file_result[path]
-    if new_dict and category_name in new_dict:
-        new_dict = new_dict[category_name]
-    new_dict = _merge_dicts(new_dict, addition_dict)
-    new_dict = { category_name : new_dict }
-    _read_config_file_result[path] = new_dict
-    yaml.dump(new_dict, stream=file, default_flow_style=False)
-    file.close()
-
-    #Merge the new information into the cached results
-    category.result_dict = _merge_dicts(category.result_dict, addition_dict)
-
-
-def add_to_mirror_config(addition_dict, scope=None):
-    """Add mirrors to the configuration files"""
-    add_to_config('mirrors', addition_dict, scope)
-
-
-def add_to_compiler_config(addition_dict, scope=None, arch=None):
-    """Add compilerss to the configuration files"""
-    if not arch:
-        arch = spack.architecture.sys_type()
-    add_to_config('compilers', { arch : addition_dict }, scope)
-    clear_config_caches()
-
-
-def remove_from_config(category_name, key_to_rm, scope=None):
-    """Remove a configuration key and write a new configuration to disk"""
-    global config_scopes
-    get_config(category_name)
-    scopes_to_rm_from = [scope] if scope else [s for s,p in config_scopes]
-    category = _config_sections[category_name]
-
-    rmd_something = False
-    for s in scopes_to_rm_from:
-        path = get_config_scope_filename(scope, category_name)
-        result = _read_config_file(path)
-        if not result:
+        scopes = [validate_scope(scope)]
+
+    for scope in scopes:
+        # read potentially cached data from the scope.
+        data = scope.get_section(section)
+
+        # Skip empty configs
+        if not data or not isinstance(data, dict):
             continue
-        if not key_to_rm in result[category_name]:
+
+        # Allow complete override of site config with '<section>::'
+        override_key = section + ':'
+        if not (section in data or override_key in data):
+            tty.warn("Skipping bad configuration file: '%s'" % scope.path)
             continue
-        with open(path, 'w') as f:
-            result[category_name].pop(key_to_rm, None)
-            yaml.dump(result, stream=f, default_flow_style=False)
-            category.result_dict.pop(key_to_rm, None)
-            rmd_something = True
-    return rmd_something
-
-
-"""Print a configuration to stdout"""
-def print_category(category_name):
-    if not category_name in _config_sections:
-        tty.die("Unknown config category %s.  Valid options are: %s" %
-                (category_name, ", ".join([s for s in _config_sections])))
-    yaml.dump(get_config(category_name), stream=sys.stdout, default_flow_style=False)
+
+        if override_key in data:
+            merged_section = data[override_key]
+        else:
+            merged_section = _merge_yaml(merged_section, data[section])
+
+    return merged_section
+
+
+def get_config_filename(scope, section):
+    """For some scope and section, get the name of the configuration file"""
+    scope = validate_scope(scope)
+    return scope.get_section_filename(section)
+
+
+def update_config(section, update_data, scope=None):
+    """Update the configuration file for a particular scope.
+
+       Overwrites contents of a section in a scope with update_data,
+       then writes out the config file.
+
+       update_data should have the top-level section name stripped off
+       (it will be re-added).  Data itself can be a list, dict, or any
+       other yaml-ish structure.
+
+    """
+    # read in the config to ensure we've got current data
+    get_config(section)
+
+    validate_section_name(section)       # validate section name
+    scope = validate_scope(scope)   # get ConfigScope object from string.
+
+    # read only the requested section's data.
+    scope.sections[section] = { section : update_data }
+    scope.write_section(section)
+
+
+def print_section(section):
+    """Print a configuration to stdout."""
+    try:
+        data = syaml.syaml_dict()
+        data[section] = get_config(section)
+        syaml.dump(data, stream=sys.stdout, default_flow_style=False)
+    except (yaml.YAMLError, IOError) as e:
+        raise ConfigError("Error reading configuration: %s" % section)
+
+
+class ConfigError(SpackError): pass
+class ConfigFileError(ConfigError): pass
+
+def get_path(path, data):
+    if path:
+        return get_path(path[1:], data[path[0]])
+    else:
+        return data
+
+class ConfigFormatError(ConfigError):
+    """Raised when a configuration format does not match its schema."""
+    def __init__(self, validation_error, data):
+        # Try to get line number from erroneous instance and its parent
+        instance_mark = getattr(validation_error.instance, '_start_mark', None)
+        parent_mark = getattr(validation_error.parent, '_start_mark', None)
+        path = getattr(validation_error, 'path', None)
+
+        # Try really hard to get the parent (which sometimes is not
+        # set) This digs it out of the validated structure if it's not
+        # on the validation_error.
+        if not parent_mark:
+            parent_path = list(path)[:-1]
+            parent = get_path(parent_path, data)
+            if path[-1] in parent:
+                if isinstance(parent, dict):
+                    keylist = parent.keys()
+                elif isinstance(parent, list):
+                    keylist = parent
+                idx = keylist.index(path[-1])
+                parent_mark = getattr(keylist[idx], '_start_mark', None)
+
+        if instance_mark:
+            location = '%s:%d' % (instance_mark.name, instance_mark.line + 1)
+        elif parent_mark:
+            location = '%s:%d' % (parent_mark.name, parent_mark.line + 1)
+        elif path:
+            location = 'At ' + ':'.join(path)
+        else:
+            location = '<unknown line>'
+
+        message = '%s: %s' % (location, validation_error.message)
+        super(ConfigError, self).__init__(message)
+
+class ConfigSanityError(ConfigFormatError):
+    """Same as ConfigFormatError, raised when config is written by Spack."""
diff --git a/lib/spack/spack/database.py b/lib/spack/spack/database.py
index a6f1cc5077..0fa18db34b 100644
--- a/lib/spack/spack/database.py
+++ b/lib/spack/spack/database.py
@@ -54,7 +54,7 @@ import spack.spec
 from spack.version import Version
 from spack.spec import Spec
 from spack.error import SpackError
-from spack.packages import UnknownPackageError
+from spack.repository import UnknownPackageError
 
 # DB goes in this directory underneath the root
 _db_dirname = '.spack-db'
@@ -215,7 +215,6 @@ class Database(object):
         # Specs from the database need to be marked concrete because
         # they represent actual installations.
         spec._mark_concrete()
-
         return spec
 
 
@@ -554,7 +553,7 @@ class Database(object):
             for key, rec in self._data.items():
                 if installed is not any and rec.installed != installed:
                     continue
-                if known is not any and spack.db.exists(rec.spec.name) != known:
+                if known is not any and spack.repo.exists(rec.spec.name) != known:
                     continue
                 if query_spec is any or rec.spec.satisfies(query_spec):
                     results.append(rec.spec)
diff --git a/lib/spack/spack/directives.py b/lib/spack/spack/directives.py
index aa9fbd8d33..0b98211cb9 100644
--- a/lib/spack/spack/directives.py
+++ b/lib/spack/spack/directives.py
@@ -244,11 +244,10 @@ def patch(pkg, url_or_filename, level=1, when=None):
     if when is None:
         when = pkg.name
     when_spec = parse_anonymous_spec(when, pkg.name)
-
     cur_patches = pkg.patches.setdefault(when_spec, [])
     # if this spec is identical to some other, then append this
     # patch to the existing list.
-    cur_patches.append(Patch(pkg.name, url_or_filename, level))
+    cur_patches.append(Patch(pkg, url_or_filename, level))
 
 
 @directive('variants')
diff --git a/lib/spack/spack/directory_layout.py b/lib/spack/spack/directory_layout.py
index d91fbe9f4e..3e416a6a1f 100644
--- a/lib/spack/spack/directory_layout.py
+++ b/lib/spack/spack/directory_layout.py
@@ -213,7 +213,6 @@ class YamlDirectoryLayout(DirectoryLayout):
 
         # Specs read from actual installations are always concrete
         spec._mark_concrete()
-
         return spec
 
 
diff --git a/lib/spack/spack/graph.py b/lib/spack/spack/graph.py
index e8c5cfb080..f3732dfbff 100644
--- a/lib/spack/spack/graph.py
+++ b/lib/spack/spack/graph.py
@@ -523,7 +523,7 @@ def graph_dot(*specs, **kwargs):
         return '"%s"' % string
 
     if not specs:
-        specs = [p.name for p in spack.db.all_packages()]
+        specs = [p.name for p in spack.repo.all_packages()]
     else:
         roots = specs
         specs = set()
diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index fe82d58394..fba2912b75 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -374,7 +374,7 @@ class Package(object):
         self._total_time = 0.0
 
         if self.is_extension:
-            spack.db.get(self.extendee_spec)._check_extendable()
+            spack.repo.get(self.extendee_spec)._check_extendable()
 
 
     @property
@@ -566,7 +566,7 @@ class Package(object):
                     yield spec
                 continue
 
-            for pkg in spack.db.get(name).preorder_traversal(visited, **kwargs):
+            for pkg in spack.repo.get(name).preorder_traversal(visited, **kwargs):
                 yield pkg
 
 
@@ -808,6 +808,12 @@ class Package(object):
             touch(no_patches_file)
 
 
+    @property
+    def namespace(self):
+        namespace, dot, module = self.__module__.rpartition('.')
+        return namespace
+
+
     def do_fake_install(self):
         """Make a fake install directory contaiing a 'fake' file in bin."""
         mkdirp(self.prefix.bin)
@@ -886,7 +892,7 @@ class Package(object):
                 tty.warn("Keeping install prefix in place despite error.",
                          "Spack will think this package is installed." +
                          "Manually remove this directory to fix:",
-                         self.prefix)
+                         self.prefix, wrap=True)
 
 
         def real_work():
diff --git a/lib/spack/spack/packages.py b/lib/spack/spack/packages.py
deleted file mode 100644
index 080644fb90..0000000000
--- a/lib/spack/spack/packages.py
+++ /dev/null
@@ -1,210 +0,0 @@
-##############################################################################
-# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
-# Produced at the Lawrence Livermore National Laboratory.
-#
-# This file is part of Spack.
-# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
-# LLNL-CODE-647188
-#
-# For details, see https://github.com/llnl/spack
-# Please also see the LICENSE file for our notice and the LGPL.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License (as published by
-# the Free Software Foundation) version 2.1 dated February 1999.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
-# conditions of the GNU General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public License
-# along with this program; if not, write to the Free Software Foundation,
-# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-##############################################################################
-import os
-import sys
-import inspect
-import glob
-import imp
-
-import llnl.util.tty as tty
-from llnl.util.filesystem import join_path
-from llnl.util.lang import *
-
-import spack.error
-import spack.spec
-from spack.virtual import ProviderIndex
-from spack.util.naming import mod_to_class, validate_module_name
-
-# Name of module under which packages are imported
-_imported_packages_module = 'spack.packages'
-
-# Name of the package file inside a package directory
-_package_file_name = 'package.py'
-
-
-def _autospec(function):
-    """Decorator that automatically converts the argument of a single-arg
-       function to a Spec."""
-    def converter(self, spec_like, **kwargs):
-        if not isinstance(spec_like, spack.spec.Spec):
-            spec_like = spack.spec.Spec(spec_like)
-        return function(self, spec_like, **kwargs)
-    return converter
-
-
-class PackageDB(object):
-    def __init__(self, root):
-        """Construct a new package database from a root directory."""
-        self.root = root
-        self.instances = {}
-        self.provider_index = None
-
-
-    @_autospec
-    def get(self, spec, **kwargs):
-        if spec.virtual:
-            raise UnknownPackageError(spec.name)
-
-        key = hash(spec)
-        if kwargs.get('new', False):
-            if key in self.instances:
-                del self.instances[key]
-
-        if not key in self.instances:
-            package_class = self.get_class_for_package_name(spec.name)
-            try:
-                copy = spec.copy() # defensive copy.  Package owns its spec.
-                self.instances[key] = package_class(copy)
-            except Exception, e:
-                if spack.debug:
-                    sys.excepthook(*sys.exc_info())
-                raise FailedConstructorError(spec.name, e)
-
-        return self.instances[key]
-
-
-    @_autospec
-    def delete(self, spec):
-        """Force a package to be recreated."""
-        del self.instances[spec.dag_hash()]
-
-
-    def purge(self):
-        """Clear entire package instance cache."""
-        self.instances.clear()
-
-
-    @_autospec
-    def providers_for(self, vpkg_spec):
-        if self.provider_index is None:
-            self.provider_index = ProviderIndex(self.all_package_names())
-
-        providers = self.provider_index.providers_for(vpkg_spec)
-        if not providers:
-            raise UnknownPackageError(vpkg_spec.name)
-        return providers
-
-
-    @_autospec
-    def extensions_for(self, extendee_spec):
-        return [p for p in self.all_packages() if p.extends(extendee_spec)]
-
-
-    def dirname_for_package_name(self, pkg_name):
-        """Get the directory name for a particular package.  This is the
-           directory that contains its package.py file."""
-        return join_path(self.root, pkg_name)
-
-
-    def filename_for_package_name(self, pkg_name):
-        """Get the filename for the module we should load for a particular
-           package.  Packages for a pacakge DB live in
-           ``$root/<package_name>/package.py``
-
-           This will return a proper package.py path even if the
-           package doesn't exist yet, so callers will need to ensure
-           the package exists before importing.
-        """
-        validate_module_name(pkg_name)
-        pkg_dir = self.dirname_for_package_name(pkg_name)
-        return join_path(pkg_dir, _package_file_name)
-
-
-    @memoized
-    def all_package_names(self):
-        """Generator function for all packages.  This looks for
-           ``<pkg_name>/package.py`` files within the root direcotry"""
-        all_package_names = []
-        for pkg_name in os.listdir(self.root):
-            pkg_dir  = join_path(self.root, pkg_name)
-            pkg_file = join_path(pkg_dir, _package_file_name)
-            if os.path.isfile(pkg_file):
-                all_package_names.append(pkg_name)
-            all_package_names.sort()
-        return all_package_names
-
-
-    def all_packages(self):
-        for name in self.all_package_names():
-            yield self.get(name)
-
-
-    @memoized
-    def exists(self, pkg_name):
-        """Whether a package with the supplied name exists ."""
-        return os.path.exists(self.filename_for_package_name(pkg_name))
-
-
-    @memoized
-    def get_class_for_package_name(self, pkg_name):
-        """Get an instance of the class for a particular package.
-
-           This method uses Python's ``imp`` package to load python
-           source from a Spack package's ``package.py`` file.  A
-           normal python import would only load each package once, but
-           because we do this dynamically, the method needs to be
-           memoized to ensure there is only ONE package class
-           instance, per package, per database.
-        """
-        file_path = self.filename_for_package_name(pkg_name)
-
-        if os.path.exists(file_path):
-            if not os.path.isfile(file_path):
-                tty.die("Something's wrong. '%s' is not a file!" % file_path)
-            if not os.access(file_path, os.R_OK):
-                tty.die("Cannot read '%s'!" % file_path)
-        else:
-            raise UnknownPackageError(pkg_name)
-
-        class_name = mod_to_class(pkg_name)
-        try:
-            module_name = _imported_packages_module + '.' + pkg_name
-            module = imp.load_source(module_name, file_path)
-
-        except ImportError, e:
-            tty.die("Error while importing %s from %s:\n%s" % (
-                pkg_name, file_path, e.message))
-
-        cls = getattr(module, class_name)
-        if not inspect.isclass(cls):
-            tty.die("%s.%s is not a class" % (pkg_name, class_name))
-
-        return cls
-
-
-class UnknownPackageError(spack.error.SpackError):
-    """Raised when we encounter a package spack doesn't have."""
-    def __init__(self, name):
-        super(UnknownPackageError, self).__init__("Package '%s' not found." % name)
-        self.name = name
-
-
-class FailedConstructorError(spack.error.SpackError):
-    """Raised when a package's class constructor fails."""
-    def __init__(self, name, reason):
-        super(FailedConstructorError, self).__init__(
-            "Class constructor failed for package '%s'." % name,
-            str(reason))
-        self.name = name
diff --git a/lib/spack/spack/patch.py b/lib/spack/spack/patch.py
index 42f2105f52..b82a047753 100644
--- a/lib/spack/spack/patch.py
+++ b/lib/spack/spack/patch.py
@@ -41,8 +41,8 @@ class Patch(object):
     """This class describes a patch to be applied to some expanded
        source code."""
 
-    def __init__(self, pkg_name, path_or_url, level):
-        self.pkg_name = pkg_name
+    def __init__(self, pkg, path_or_url, level):
+        self.pkg_name = pkg.name
         self.path_or_url = path_or_url
         self.path = None
         self.url = None
@@ -54,7 +54,7 @@ class Patch(object):
         if '://' in path_or_url:
             self.url = path_or_url
         else:
-            pkg_dir = spack.db.dirname_for_package_name(pkg_name)
+            pkg_dir = spack.repo.dirname_for_package_name(self.pkg_name)
             self.path = join_path(pkg_dir, path_or_url)
             if not os.path.isfile(self.path):
                 raise NoSuchPatchFileError(pkg_name, self.path)
diff --git a/lib/spack/spack/repository.py b/lib/spack/spack/repository.py
new file mode 100644
index 0000000000..31596cee7a
--- /dev/null
+++ b/lib/spack/spack/repository.py
@@ -0,0 +1,747 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import os
+import exceptions
+import sys
+import inspect
+import imp
+import re
+import traceback
+from bisect import bisect_left
+from external import yaml
+
+import llnl.util.tty as tty
+from llnl.util.filesystem import join_path
+
+import spack.error
+import spack.config
+import spack.spec
+from spack.virtual import ProviderIndex
+from spack.util.naming import *
+
+#
+# Super-namespace for all packages.
+# Package modules are imported as spack.pkg.<namespace>.<pkg-name>.
+#
+repo_namespace     = 'spack.pkg'
+
+#
+# These names describe how repos should be laid out in the filesystem.
+#
+repo_config_name   = 'repo.yaml'   # Top-level filename for repo config.
+packages_dir_name  = 'packages'    # Top-level repo directory containing pkgs.
+package_file_name  = 'package.py'  # Filename for packages in a repository.
+
+# Guaranteed unused default value for some functions.
+NOT_PROVIDED = object()
+
+
+def _autospec(function):
+    """Decorator that automatically converts the argument of a single-arg
+       function to a Spec."""
+    def converter(self, spec_like, *args, **kwargs):
+        if not isinstance(spec_like, spack.spec.Spec):
+            spec_like = spack.spec.Spec(spec_like)
+        return function(self, spec_like, *args, **kwargs)
+    return converter
+
+
+def _make_namespace_module(ns):
+    module = imp.new_module(ns)
+    module.__file__ = "(spack namespace)"
+    module.__path__ = []
+    module.__package__ = ns
+    return module
+
+
+def substitute_spack_prefix(path):
+    """Replaces instances of $spack with Spack's prefix."""
+    return re.sub(r'^\$spack', spack.prefix, path)
+
+
+def canonicalize_path(path):
+    """Substitute $spack, expand user home, take abspath."""
+    path = substitute_spack_prefix(path)
+    path = os.path.expanduser(path)
+    path = os.path.abspath(path)
+    return path
+
+
+class RepoPath(object):
+    """A RepoPath is a list of repos that function as one.
+
+       It functions exactly like a Repo, but it operates on the
+       combined results of the Repos in its list instead of on a
+       single package repository.
+    """
+    def __init__(self, *repo_dirs, **kwargs):
+        # super-namespace for all packages in the RepoPath
+        self.super_namespace = kwargs.get('namespace', repo_namespace)
+
+        self.repos = []
+        self.by_namespace = NamespaceTrie()
+        self.by_path = {}
+
+        self._all_package_names = []
+        self._provider_index = None
+
+        # If repo_dirs is empty, just use the configuration
+        if not repo_dirs:
+            repo_dirs = spack.config.get_config('repos')
+            if not repo_dirs:
+                raise NoRepoConfiguredError(
+                    "Spack configuration contains no package repositories.")
+
+        # Add each repo to this path.
+        for root in repo_dirs:
+            try:
+                repo = Repo(root, self.super_namespace)
+                self.put_last(repo)
+            except RepoError as e:
+                tty.warn("Failed to initialize repository at '%s'." % root,
+                         e.message,
+                         "To remove the bad repository, run this command:",
+                         "    spack repo rm %s" % root)
+
+
+    def swap(self, other):
+        """Convenience function to make swapping repostiories easier.
+
+        This is currently used by mock tests.
+        TODO: Maybe there is a cleaner way.
+
+        """
+        attrs = ['repos',
+                 'by_namespace',
+                 'by_path',
+                 '_all_package_names',
+                 '_provider_index']
+        for attr in attrs:
+            tmp = getattr(self, attr)
+            setattr(self, attr, getattr(other, attr))
+            setattr(other, attr, tmp)
+
+
+    def _add(self, repo):
+        """Add a repository to the namespace and path indexes.
+
+        Checks for duplicates -- two repos can't have the same root
+        directory, and they provide have the same namespace.
+
+        """
+        if repo.root in self.by_path:
+            raise DuplicateRepoError("Duplicate repository: '%s'" % repo.root)
+
+        if repo.namespace in self.by_namespace:
+            raise DuplicateRepoError(
+                "Package repos '%s' and '%s' both provide namespace %s."
+                % (repo.root, self.by_namespace[repo.namespace].root, repo.namespace))
+
+        # Add repo to the pkg indexes
+        self.by_namespace[repo.full_namespace] = repo
+        self.by_path[repo.root] = repo
+
+        # add names to the cached name list
+        new_pkgs = set(repo.all_package_names())
+        new_pkgs.update(set(self._all_package_names))
+        self._all_package_names = sorted(new_pkgs, key=lambda n:n.lower())
+
+
+    def put_first(self, repo):
+        """Add repo first in the search path."""
+        self._add(repo)
+        self.repos.insert(0, repo)
+
+
+    def put_last(self, repo):
+        """Add repo last in the search path."""
+        self._add(repo)
+        self.repos.append(repo)
+
+
+    def remove(self, repo):
+        """Remove a repo from the search path."""
+        if repo in self.repos:
+            self.repos.remove(repo)
+
+
+    def get_repo(self, namespace, default=NOT_PROVIDED):
+        """Get a repository by namespace.
+        Arguments
+          namespace
+            Look up this namespace in the RepoPath, and return
+            it if found.
+
+        Optional Arguments
+          default
+            If default is provided, return it when the namespace
+            isn't found.  If not, raise an UnknownNamespaceError.
+        """
+        fullspace = '%s.%s' % (self.super_namespace, namespace)
+        if fullspace not in self.by_namespace:
+            if default == NOT_PROVIDED:
+                raise UnknownNamespaceError(namespace)
+            return default
+        return self.by_namespace[fullspace]
+
+
+    def first_repo(self):
+        """Get the first repo in precedence order."""
+        return self.repos[0] if self.repos else None
+
+
+    def all_package_names(self):
+        """Return all unique package names in all repositories."""
+        return self._all_package_names
+
+
+    def all_packages(self):
+        for name in self.all_package_names():
+            yield self.get(name)
+
+
+    @_autospec
+    def providers_for(self, vpkg_spec):
+        if self._provider_index is None:
+            self._provider_index = ProviderIndex(self.all_package_names())
+
+        providers = self._provider_index.providers_for(vpkg_spec)
+        if not providers:
+            raise UnknownPackageError(vpkg_spec.name)
+        return providers
+
+
+    def find_module(self, fullname, path=None):
+        """Implements precedence for overlaid namespaces.
+
+        Loop checks each namespace in self.repos for packages, and
+        also handles loading empty containing namespaces.
+
+        """
+        # namespaces are added to repo, and package modules are leaves.
+        namespace, dot, module_name = fullname.rpartition('.')
+
+        # If it's a module in some repo, or if it is the repo's
+        # namespace, let the repo handle it.
+        for repo in self.repos:
+            if namespace == repo.full_namespace:
+                if repo.real_name(module_name):
+                    return repo
+            elif fullname == repo.full_namespace:
+                return repo
+
+        # No repo provides the namespace, but it is a valid prefix of
+        # something in the RepoPath.
+        if self.by_namespace.is_prefix(fullname):
+            return self
+
+        return None
+
+
+    def load_module(self, fullname):
+        """Handles loading container namespaces when necessary.
+
+        See ``Repo`` for how actual package modules are loaded.
+        """
+        if fullname in sys.modules:
+            return sys.modules[fullname]
+
+        # partition fullname into prefix and module name.
+        namespace, dot, module_name = fullname.rpartition('.')
+
+        if not self.by_namespace.is_prefix(fullname):
+            raise ImportError("No such Spack repo: %s" % fullname)
+
+        module = _make_namespace_module(namespace)
+        module.__loader__ = self
+        sys.modules[fullname] = module
+        return module
+
+
+    @_autospec
+    def repo_for_pkg(self, spec):
+        """Given a spec, get the repository for its package."""
+        # If the spec already has a namespace, then return the
+        # corresponding repo if we know about it.
+        if spec.namespace:
+            fullspace = '%s.%s' % (self.super_namespace, spec.namespace)
+            if fullspace not in self.by_namespace:
+                raise UnknownNamespaceError(spec.namespace)
+            return self.by_namespace[fullspace]
+
+        # If there's no namespace, search in the RepoPath.
+        for repo in self.repos:
+            if spec.name in repo:
+                return repo
+        else:
+            raise UnknownPackageError(spec.name)
+
+
+    @_autospec
+    def get(self, spec, new=False):
+        """Find a repo that contains the supplied spec's package.
+
+           Raises UnknownPackageError if not found.
+        """
+        return self.repo_for_pkg(spec).get(spec)
+
+
+    def dirname_for_package_name(self, pkg_name):
+        return self.repo_for_pkg(pkg_name).dirname_for_package_name(pkg_name)
+
+
+    def filename_for_package_name(self, pkg_name):
+        return self.repo_for_pkg(pkg_name).filename_for_package_name(pkg_name)
+
+
+    def exists(self, pkg_name):
+        return any(repo.exists(pkg_name) for repo in self.repos)
+
+
+    def __contains__(self, pkg_name):
+        return self.exists(pkg_name)
+
+
+
+class Repo(object):
+    """Class representing a package repository in the filesystem.
+
+    Each package repository must have a top-level configuration file
+    called `repo.yaml`.
+
+    Currently, `repo.yaml` this must define:
+
+    `namespace`:
+        A Python namespace where the repository's packages should live.
+
+    """
+    def __init__(self, root, namespace=repo_namespace):
+        """Instantiate a package repository from a filesystem path.
+
+        Arguments:
+        root        The root directory of the repository.
+
+        namespace   A super-namespace that will contain the repo-defined
+                    namespace (this is generally jsut `spack.pkg`). The
+                    super-namespace is Spack's way of separating repositories
+                    from other python namespaces.
+
+        """
+        # Root directory, containing _repo.yaml and package dirs
+        # Allow roots to by spack-relative by starting with '$spack'
+        self.root = canonicalize_path(root)
+
+        # super-namespace for all packages in the Repo
+        self.super_namespace = namespace
+
+        # check and raise BadRepoError on fail.
+        def check(condition, msg):
+            if not condition: raise BadRepoError(msg)
+
+        # Validate repository layout.
+        self.config_file   = join_path(self.root, repo_config_name)
+        check(os.path.isfile(self.config_file),
+              "No %s found in '%s'" % (repo_config_name, root))
+        self.packages_path = join_path(self.root, packages_dir_name)
+        check(os.path.isdir(self.packages_path),
+              "No directory '%s' found in '%s'" % (repo_config_name, root))
+
+        # Read configuration and validate namespace
+        config = self._read_config()
+        check('namespace' in config, '%s must define a namespace.'
+              % join_path(root, repo_config_name))
+
+        self.namespace = config['namespace']
+        check(re.match(r'[a-zA-Z][a-zA-Z0-9_.]+', self.namespace),
+              ("Invalid namespace '%s' in repo '%s'. "  % (self.namespace, self.root)) +
+              "Namespaces must be valid python identifiers separated by '.'")
+
+        # Set up 'full_namespace' to include the super-namespace
+        if self.super_namespace:
+            self.full_namespace = "%s.%s" % (self.super_namespace, self.namespace)
+        else:
+            self.full_namespace = self.namespace
+
+        # Keep name components around for checking prefixes.
+        self._names = self.full_namespace.split('.')
+
+        # These are internal cache variables.
+        self._modules = {}
+        self._classes = {}
+        self._instances = {}
+        self._provider_index = None
+        self._all_package_names = None
+
+        # make sure the namespace for packages in this repo exists.
+        self._create_namespace()
+
+
+    def _create_namespace(self):
+        """Create this repo's namespace module and insert it into sys.modules.
+
+        Ensures that modules loaded via the repo have a home, and that
+        we don't get runtime warnings from Python's module system.
+
+        """
+        parent = None
+        for l in range(1, len(self._names)+1):
+            ns = '.'.join(self._names[:l])
+            if not ns in sys.modules:
+                module = _make_namespace_module(ns)
+                module.__loader__ = self
+                sys.modules[ns] = module
+
+                # Ensure the namespace is an atrribute of its parent,
+                # if it has not been set by something else already.
+                #
+                # This ensures that we can do things like:
+                #    import spack.pkg.builtin.mpich as mpich
+                if parent:
+                    modname = self._names[l-1]
+                    if not hasattr(parent, modname):
+                        setattr(parent, modname, module)
+            else:
+                # no need to set up a module, but keep track of the parent.
+                module = sys.modules[ns]
+            parent = module
+
+
+    def real_name(self, import_name):
+        """Allow users to import Spack packages using Python identifiers.
+
+        A python identifier might map to many different Spack package
+        names due to hyphen/underscore ambiguity.
+
+        Easy example:
+            num3proxy   -> 3proxy
+
+        Ambiguous:
+            foo_bar -> foo_bar, foo-bar
+
+        More ambiguous:
+            foo_bar_baz -> foo_bar_baz, foo-bar-baz, foo_bar-baz, foo-bar_baz
+        """
+        if import_name in self:
+            return import_name
+
+        options = possible_spack_module_names(import_name)
+        options.remove(import_name)
+        for name in options:
+            if name in self:
+                return name
+        return None
+
+
+    def is_prefix(self, fullname):
+        """True if fullname is a prefix of this Repo's namespace."""
+        parts = fullname.split('.')
+        return self._names[:len(parts)] == parts
+
+
+    def find_module(self, fullname, path=None):
+        """Python find_module import hook.
+
+        Returns this Repo if it can load the module; None if not.
+        """
+        if self.is_prefix(fullname):
+            return self
+
+        namespace, dot, module_name = fullname.rpartition('.')
+        if namespace == self.full_namespace:
+            if self.real_name(module_name):
+                return self
+
+        return None
+
+
+    def load_module(self, fullname):
+        """Python importer load hook.
+
+        Tries to load the module; raises an ImportError if it can't.
+        """
+        if fullname in sys.modules:
+            return sys.modules[fullname]
+
+        namespace, dot, module_name = fullname.rpartition('.')
+
+        if self.is_prefix(fullname):
+            module = _make_namespace_module(fullname)
+
+        elif namespace == self.full_namespace:
+            real_name = self.real_name(module_name)
+            if not real_name:
+                raise ImportError("No module %s in %s" % (module_name, self))
+            module = self._get_pkg_module(real_name)
+
+        else:
+            raise ImportError("No module %s in %s" % (fullname, self))
+
+        module.__loader__ = self
+        sys.modules[fullname] = module
+        return module
+
+
+    def _read_config(self):
+        """Check for a YAML config file in this db's root directory."""
+        try:
+            with open(self.config_file) as reponame_file:
+                yaml_data = yaml.load(reponame_file)
+
+                if (not yaml_data or 'repo' not in yaml_data or
+                    not isinstance(yaml_data['repo'], dict)):
+                    tty.die("Invalid %s in repository %s"
+                            % (repo_config_name, self.root))
+
+                return yaml_data['repo']
+
+        except exceptions.IOError, e:
+            tty.die("Error reading %s when opening %s"
+                    % (self.config_file, self.root))
+
+
+    @_autospec
+    def get(self, spec, new=False):
+        if spec.virtual:
+            raise UnknownPackageError(spec.name)
+
+        if spec.namespace and spec.namespace != self.namespace:
+            raise UnknownPackageError("Repository %s does not contain package %s."
+                                      % (self.namespace, spec.fullname))
+
+        key = hash(spec)
+        if new or key not in self._instances:
+            package_class = self._get_pkg_class(spec.name)
+            try:
+                copy = spec.copy() # defensive copy.  Package owns its spec.
+                self._instances[key] = package_class(copy)
+            except Exception, e:
+                if spack.debug:
+                    sys.excepthook(*sys.exc_info())
+                raise FailedConstructorError(spec.fullname, *sys.exc_info())
+
+        return self._instances[key]
+
+
+    def purge(self):
+        """Clear entire package instance cache."""
+        self._instances.clear()
+
+
+    @_autospec
+    def providers_for(self, vpkg_spec):
+        if self._provider_index is None:
+            self._provider_index = ProviderIndex(self.all_package_names())
+
+        providers = self._provider_index.providers_for(vpkg_spec)
+        if not providers:
+            raise UnknownPackageError(vpkg_spec.name)
+        return providers
+
+
+    @_autospec
+    def extensions_for(self, extendee_spec):
+        return [p for p in self.all_packages() if p.extends(extendee_spec)]
+
+
+    def _check_namespace(self, spec):
+        """Check that the spec's namespace is the same as this repository's."""
+        if spec.namespace and spec.namespace != self.namespace:
+            raise UnknownNamespaceError(spec.namespace)
+
+
+    @_autospec
+    def dirname_for_package_name(self, spec):
+        """Get the directory name for a particular package.  This is the
+           directory that contains its package.py file."""
+        self._check_namespace(spec)
+        return join_path(self.packages_path, spec.name)
+
+
+    @_autospec
+    def filename_for_package_name(self, spec):
+        """Get the filename for the module we should load for a particular
+           package.  Packages for a Repo live in
+           ``$root/<package_name>/package.py``
+
+           This will return a proper package.py path even if the
+           package doesn't exist yet, so callers will need to ensure
+           the package exists before importing.
+        """
+        self._check_namespace(spec)
+        pkg_dir = self.dirname_for_package_name(spec.name)
+        return join_path(pkg_dir, package_file_name)
+
+
+    def all_package_names(self):
+        """Returns a sorted list of all package names in the Repo."""
+        if self._all_package_names is None:
+            self._all_package_names = []
+
+            for pkg_name in os.listdir(self.packages_path):
+                # Skip non-directories in the package root.
+                pkg_dir = join_path(self.packages_path, pkg_name)
+                if not os.path.isdir(pkg_dir):
+                    continue
+
+                # Skip directories without a package.py in them.
+                pkg_file = join_path(self.packages_path, pkg_name, package_file_name)
+                if not os.path.isfile(pkg_file):
+                    continue
+
+                # Warn about invalid names that look like packages.
+                if not valid_module_name(pkg_name):
+                    tty.warn("Skipping package at %s. '%s' is not a valid Spack module name."
+                             % (pkg_dir, pkg_name))
+                    continue
+
+                # All checks passed.  Add it to the list.
+                self._all_package_names.append(pkg_name)
+            self._all_package_names.sort()
+
+        return self._all_package_names
+
+
+    def all_packages(self):
+        for name in self.all_package_names():
+            yield self.get(name)
+
+
+    def exists(self, pkg_name):
+        """Whether a package with the supplied name exists."""
+        # This does a binary search in the sorted list.
+        idx = bisect_left(self.all_package_names(), pkg_name)
+        return (idx < len(self._all_package_names) and
+                self._all_package_names[idx] == pkg_name)
+
+
+    def _get_pkg_module(self, pkg_name):
+        """Create a module for a particular package.
+
+        This caches the module within this Repo *instance*.  It does
+        *not* add it to ``sys.modules``.  So, you can construct
+        multiple Repos for testing and ensure that the module will be
+        loaded once per repo.
+
+        """
+        if pkg_name not in self._modules:
+            file_path = self.filename_for_package_name(pkg_name)
+
+            if not os.path.exists(file_path):
+                raise UnknownPackageError(pkg_name, self)
+
+            if not os.path.isfile(file_path):
+                tty.die("Something's wrong. '%s' is not a file!" % file_path)
+
+            if not os.access(file_path, os.R_OK):
+                tty.die("Cannot read '%s'!" % file_path)
+
+            # e.g., spack.pkg.builtin.mpich
+            fullname = "%s.%s" % (self.full_namespace, pkg_name)
+
+            module = imp.load_source(fullname, file_path)
+            module.__package__ = self.full_namespace
+            module.__loader__ = self
+            self._modules[pkg_name] = module
+
+        return self._modules[pkg_name]
+
+
+    def _get_pkg_class(self, pkg_name):
+        """Get the class for the package out of its module.
+
+        First loads (or fetches from cache) a module for the
+        package. Then extracts the package class from the module
+        according to Spack's naming convention.
+        """
+        class_name = mod_to_class(pkg_name)
+        module = self._get_pkg_module(pkg_name)
+
+        cls = getattr(module, class_name)
+        if not inspect.isclass(cls):
+            tty.die("%s.%s is not a class" % (pkg_name, class_name))
+
+        return cls
+
+
+    def __str__(self):
+        return "[Repo '%s' at '%s']" % (self.namespace, self.root)
+
+
+    def __repr__(self):
+        return self.__str__()
+
+
+    def __contains__(self, pkg_name):
+        return self.exists(pkg_name)
+
+
+class RepoError(spack.error.SpackError):
+    """Superclass for repository-related errors."""
+
+
+class NoRepoConfiguredError(RepoError):
+    """Raised when there are no repositories configured."""
+
+
+class BadRepoError(RepoError):
+    """Raised when repo layout is invalid."""
+
+
+class DuplicateRepoError(RepoError):
+    """Raised when duplicate repos are added to a RepoPath."""
+
+
+class PackageLoadError(spack.error.SpackError):
+    """Superclass for errors related to loading packages."""
+
+
+class UnknownPackageError(PackageLoadError):
+    """Raised when we encounter a package spack doesn't have."""
+    def __init__(self, name, repo=None):
+        msg = None
+        if repo:
+            msg = "Package %s not found in repository %s." % (name, repo)
+        else:
+            msg = "Package %s not found." % name
+        super(UnknownPackageError, self).__init__(msg)
+        self.name = name
+
+
+class UnknownNamespaceError(PackageLoadError):
+    """Raised when we encounter an unknown namespace"""
+    def __init__(self, namespace):
+        super(UnknownNamespaceError, self).__init__(
+            "Unknown namespace: %s" % namespace)
+
+
+class FailedConstructorError(PackageLoadError):
+    """Raised when a package's class constructor fails."""
+    def __init__(self, name, exc_type, exc_obj, exc_tb):
+        super(FailedConstructorError, self).__init__(
+            "Class constructor failed for package '%s'." % name,
+            '\nCaused by:\n' +
+            ('%s: %s\n' % (exc_type.__name__, exc_obj)) +
+            ''.join(traceback.format_tb(exc_tb)))
+        self.name = name
diff --git a/lib/spack/spack/resource.py b/lib/spack/spack/resource.py
index 8d081b45c9..2bf92947fd 100644
--- a/lib/spack/spack/resource.py
+++ b/lib/spack/spack/resource.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://scalability-llnl.github.io/spack
+# For details, see https://llnl.github.io/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -22,9 +22,11 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-"""
-Describes an optional resource needed for a build. Typically a bunch of sources that can be built in-tree within another
+"""Describes an optional resource needed for a build.
+
+Typically a bunch of sources that can be built in-tree within another
 package to enable optional features.
+
 """
 
 
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index 037ec97a5e..10e246bf2e 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -412,6 +412,7 @@ class Spec(object):
         self.dependencies = other.dependencies
         self.variants = other.variants
         self.variants.spec = self
+        self.namespace = other.namespace
 
         # Specs are by default not assumed to be normal, but in some
         # cases we've read them from a file want to assume normal.
@@ -464,6 +465,13 @@ class Spec(object):
         self.dependencies[spec.name] = spec
         spec.dependents[self.name] = self
 
+    #
+    # Public interface
+    #
+    @property
+    def fullname(self):
+        return '%s.%s' % (self.namespace, self.name) if self.namespace else self.name
+
 
     @property
     def root(self):
@@ -486,7 +494,7 @@ class Spec(object):
 
     @property
     def package(self):
-        return spack.db.get(self)
+        return spack.repo.get(self)
 
 
     @property
@@ -504,7 +512,7 @@ class Spec(object):
     @staticmethod
     def is_virtual(name):
         """Test if a name is virtual without requiring a Spec."""
-        return not spack.db.exists(name)
+        return not spack.repo.exists(name)
 
 
     @property
@@ -517,11 +525,13 @@ class Spec(object):
             return True
 
         self._concrete = bool(not self.virtual
+                              and self.namespace is not None
                               and self.versions.concrete
                               and self.variants.concrete
                               and self.architecture
                               and self.compiler and self.compiler.concrete
                               and self.dependencies.concrete)
+
         return self._concrete
 
 
@@ -657,6 +667,12 @@ class Spec(object):
             'dependencies' : dict((d, self.dependencies[d].dag_hash())
                                   for d in sorted(self.dependencies))
         }
+
+        # Older concrete specs do not have a namespace.  Omit for
+        # consistent hashing.
+        if not self.concrete or self.namespace:
+            d['namespace'] = self.namespace
+
         if self.compiler:
             d.update(self.compiler.to_dict())
         else:
@@ -681,6 +697,7 @@ class Spec(object):
         node = node[name]
 
         spec = Spec(name)
+        spec.namespace = node.get('namespace', None)
         spec.versions = VersionList.from_dict(node)
         spec.architecture = node['arch']
 
@@ -797,7 +814,7 @@ class Spec(object):
                 return changed
 
             for spec in virtuals:
-                providers = spack.db.providers_for(spec)
+                providers = spack.repo.providers_for(spec)
                 concrete = spack.concretizer.choose_provider(spec, providers)
                 concrete = concrete.copy()
                 spec._replace_with(concrete)
@@ -833,6 +850,19 @@ class Spec(object):
             changed = any(changes)
             force=True
 
+        for s in self.traverse():
+            # After concretizing, assign namespaces to anything left.
+            # Note that this doesn't count as a "change".  The repository
+            # configuration is constant throughout a spack run, and
+            # normalize and concretize evaluate Packages using Repo.get(),
+            # which respects precedence.  So, a namespace assignment isn't
+            # changing how a package name would have been interpreted and
+            # we can do it as late as possible to allow as much
+            # compatibility across repositories as possible.
+            if s.namespace is None:
+                s.namespace = spack.repo.repo_for_pkg(s.name).namespace
+
+        # Mark everything in the spec as concrete, as well.
         self._mark_concrete()
 
 
@@ -919,7 +949,7 @@ class Spec(object):
         the dependency.  If no conditions are True (and we don't
         depend on it), return None.
         """
-        pkg = spack.db.get(self.name)
+        pkg = spack.repo.get(self.fullname)
         conditions = pkg.dependencies[name]
 
         # evaluate when specs to figure out constraints on the dependency.
@@ -1047,7 +1077,7 @@ class Spec(object):
         any_change = False
         changed = True
 
-        pkg = spack.db.get(self.name)
+        pkg = spack.repo.get(self.fullname)
         while changed:
             changed = False
             for dep_name in pkg.dependencies:
@@ -1068,18 +1098,17 @@ class Spec(object):
            the root, and ONLY the ones that were explicitly provided are there.
            Normalization turns a partial flat spec into a DAG, where:
 
-           1. ALL dependencies of the root package are in the DAG.
-           2. Each node's dependencies dict only contains its direct deps.
+           1. Known dependencies of the root package are in the DAG.
+           2. Each node's dependencies dict only contains its known direct deps.
            3. There is only ONE unique spec for each package in the DAG.
 
               * This includes virtual packages.  If there a non-virtual
                 package that provides a virtual package that is in the spec,
                 then we replace the virtual package with the non-virtual one.
 
-           4. The spec DAG matches package DAG, including default variant values.
-
            TODO: normalize should probably implement some form of cycle detection,
            to ensure that the spec is actually a DAG.
+
         """
         if self._normal and not force:
             return False
@@ -1125,7 +1154,7 @@ class Spec(object):
         for spec in self.traverse():
             # Don't get a package for a virtual name.
             if not spec.virtual:
-                spack.db.get(spec.name)
+                spack.repo.get(spec.fullname)
 
             # validate compiler in addition to the package name.
             if spec.compiler:
@@ -1148,6 +1177,10 @@ class Spec(object):
         if not self.name == other.name:
             raise UnsatisfiableSpecNameError(self.name, other.name)
 
+        if other.namespace is not None:
+            if self.namespace is not None and other.namespace != self.namespace:
+                raise UnsatisfiableSpecNameError(self.fullname, other.fullname)
+
         if not self.versions.overlaps(other.versions):
             raise UnsatisfiableVersionSpecError(self.versions, other.versions)
 
@@ -1191,7 +1224,7 @@ class Spec(object):
 
         # TODO: might want more detail than this, e.g. specific deps
         # in violation. if this becomes a priority get rid of this
-        # check and be more specici about what's wrong.
+        # check and be more specific about what's wrong.
         if not other.satisfies_dependencies(self):
             raise UnsatisfiableDependencySpecError(other, self)
 
@@ -1264,7 +1297,7 @@ class Spec(object):
 
         # A concrete provider can satisfy a virtual dependency.
         if not self.virtual and other.virtual:
-            pkg = spack.db.get(self.name)
+            pkg = spack.repo.get(self.fullname)
             if pkg.provides(other.name):
                 for provided, when_spec in pkg.provided.items():
                     if self.satisfies(when_spec, deps=False, strict=strict):
@@ -1276,6 +1309,11 @@ class Spec(object):
         if self.name != other.name:
             return False
 
+        # namespaces either match, or other doesn't require one.
+        if other.namespace is not None:
+            if self.namespace is not None and self.namespace != other.namespace:
+                return False
+
         if self.versions and other.versions:
             if not self.versions.satisfies(other.versions, strict=strict):
                 return False
@@ -1375,6 +1413,7 @@ class Spec(object):
         self.dependencies = DependencyMap()
         self.variants = other.variants.copy()
         self.variants.spec = self
+        self.namespace = other.namespace
 
         # If we copy dependencies, preserve DAG structure in the new spec
         if kwargs.get('deps', True):
@@ -1493,6 +1532,7 @@ class Spec(object):
     def _cmp_node(self):
         """Comparison key for just *this node* and not its deps."""
         return (self.name,
+                self.namespace,
                 self.versions,
                 self.variants,
                 self.architecture,
@@ -1530,6 +1570,7 @@ class Spec(object):
            in the format string.  The format strings you can provide are::
 
                $_   Package name
+               $.   Full package name (with namespace)
                $@   Version
                $%   Compiler
                $%@  Compiler & compiler version
@@ -1577,6 +1618,8 @@ class Spec(object):
 
                 if c == '_':
                     out.write(fmt % self.name)
+                elif c == '.':
+                    out.write(fmt % self.fullname)
                 elif c == '@':
                     if self.versions and self.versions != _any_version:
                         write(fmt % (c + str(self.versions)), c)
@@ -1725,17 +1768,23 @@ class SpecParser(spack.parse.Parser):
     def spec(self):
         """Parse a spec out of the input.  If a spec is supplied, then initialize
            and return it instead of creating a new one."""
-        self.check_identifier()
+
+        spec_namespace, dot, spec_name = self.token.value.rpartition('.')
+        if not spec_namespace:
+            spec_namespace = None
+
+        self.check_identifier(spec_name)
 
         # This will init the spec without calling __init__.
         spec = Spec.__new__(Spec)
-        spec.name = self.token.value
+        spec.name = spec_name
         spec.versions = VersionList()
         spec.variants = VariantMap(spec)
         spec.architecture = None
         spec.compiler = None
         spec.dependents   = DependencyMap()
         spec.dependencies = DependencyMap()
+        spec.namespace = spec_namespace
 
         spec._normal = False
         spec._concrete = False
@@ -1829,12 +1878,14 @@ class SpecParser(spack.parse.Parser):
         return compiler
 
 
-    def check_identifier(self):
+    def check_identifier(self, id=None):
         """The only identifiers that can contain '.' are versions, but version
            ids are context-sensitive so we have to check on a case-by-case
            basis. Call this if we detect a version id where it shouldn't be.
         """
-        if '.' in self.token.value:
+        if not id:
+            id = self.token.value
+        if '.' in id:
             self.last_token_error("Identifier cannot contain '.'")
 
 
diff --git a/lib/spack/spack/stage.py b/lib/spack/spack/stage.py
index 76ca7273cb..31635a854a 100644
--- a/lib/spack/spack/stage.py
+++ b/lib/spack/spack/stage.py
@@ -26,6 +26,7 @@ import os
 import re
 import shutil
 import tempfile
+from urlparse import urljoin
 
 import llnl.util.tty as tty
 from llnl.util.filesystem import *
@@ -250,7 +251,8 @@ class Stage(object):
         # TODO: CompositeFetchStrategy here.
         self.skip_checksum_for_mirror = True
         if self.mirror_path:
-            urls = ["%s/%s" % (m, self.mirror_path) for m in _get_mirrors()]
+            mirrors = spack.config.get_config('mirrors')
+            urls = [urljoin(u, self.mirror_path) for name, u in mirrors.items()]
 
             # If this archive is normally fetched from a tarball URL,
             # then use the same digest.  `spack mirror` ensures that
@@ -370,7 +372,7 @@ class DIYStage(object):
 
 def _get_mirrors():
     """Get mirrors from spack configuration."""
-    config = spack.config.get_mirror_config()
+    config = spack.config.get_config('mirrors')
     return [val for name, val in config.iteritems()]
 
 
diff --git a/lib/spack/spack/test/__init__.py b/lib/spack/spack/test/__init__.py
index 3b5d9e5a95..a569cbbf35 100644
--- a/lib/spack/spack/test/__init__.py
+++ b/lib/spack/spack/test/__init__.py
@@ -62,7 +62,9 @@ test_names = ['versions',
               'configure_guess',
               'unit_install',
               'lock',
-              'database']
+              'database',
+              'namespace_trie',
+              'yaml']
 
 
 def list_tests():
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index 2f8e0c7ec0..7f2938aec5 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -125,22 +125,22 @@ class ConcretizeTest(MockPackagesTest):
            we ask for some advanced version.
         """
         self.assertTrue(not any(spec.satisfies('mpich2@:1.0')
-                                for spec in spack.db.providers_for('mpi@2.1')))
+                                for spec in spack.repo.providers_for('mpi@2.1')))
 
         self.assertTrue(not any(spec.satisfies('mpich2@:1.1')
-                                for spec in spack.db.providers_for('mpi@2.2')))
+                                for spec in spack.repo.providers_for('mpi@2.2')))
 
         self.assertTrue(not any(spec.satisfies('mpich2@:1.1')
-                                for spec in spack.db.providers_for('mpi@2.2')))
+                                for spec in spack.repo.providers_for('mpi@2.2')))
 
         self.assertTrue(not any(spec.satisfies('mpich@:1')
-                                for spec in spack.db.providers_for('mpi@2')))
+                                for spec in spack.repo.providers_for('mpi@2')))
 
         self.assertTrue(not any(spec.satisfies('mpich@:1')
-                                for spec in spack.db.providers_for('mpi@3')))
+                                for spec in spack.repo.providers_for('mpi@3')))
 
         self.assertTrue(not any(spec.satisfies('mpich2')
-                                for spec in spack.db.providers_for('mpi@3')))
+                                for spec in spack.repo.providers_for('mpi@3')))
 
 
     def test_virtual_is_fully_expanded_for_callpath(self):
diff --git a/lib/spack/spack/test/config.py b/lib/spack/spack/test/config.py
index ed11e34c69..d8be5a855b 100644
--- a/lib/spack/spack/test/config.py
+++ b/lib/spack/spack/test/config.py
@@ -26,49 +26,95 @@ import unittest
 import shutil
 import os
 from tempfile import mkdtemp
+from ordereddict_backport import OrderedDict
 import spack
-from spack.packages import PackageDB
+import spack.config
 from spack.test.mock_packages_test import *
 
+# Some sample compiler config data
+a_comps =  {
+    "all": {
+        "gcc@4.7.3" : {
+            "cc" : "/gcc473",
+            "cxx": "/g++473",
+            "f77": None,
+            "fc" : None },
+        "gcc@4.5.0" : {
+            "cc" : "/gcc450",
+            "cxx": "/g++450",
+            "f77": "/gfortran",
+            "fc" : "/gfortran" },
+        "clang@3.3"  : {
+            "cc" : "<overwritten>",
+            "cxx": "<overwritten>",
+            "f77": "<overwritten>",
+            "fc" : "<overwritten>" }
+    }
+}
+
+b_comps = {
+    "all": {
+        "icc@10.0" : {
+            "cc" : "/icc100",
+            "cxx": "/icc100",
+            "f77": None,
+            "fc" : None },
+        "icc@11.1" : {
+            "cc" : "/icc111",
+            "cxx": "/icp111",
+            "f77": "/ifort",
+            "fc" : "/ifort" },
+        "clang@3.3" : {
+            "cc" : "/clang",
+            "cxx": "/clang++",
+            "f77": None,
+            "fc" : None}
+    }
+}
+
 class ConfigTest(MockPackagesTest):
 
     def setUp(self):
-        self.initmock()
+        super(ConfigTest, self).setUp()
         self.tmp_dir = mkdtemp('.tmp', 'spack-config-test-')
-        spack.config.config_scopes = [('test_low_priority', os.path.join(self.tmp_dir, 'low')),
-                                      ('test_high_priority', os.path.join(self.tmp_dir, 'high'))]
+        spack.config.config_scopes = OrderedDict()
+        spack.config.ConfigScope('test_low_priority', os.path.join(self.tmp_dir, 'low'))
+        spack.config.ConfigScope('test_high_priority', os.path.join(self.tmp_dir, 'high'))
 
     def tearDown(self):
-        self.cleanmock()
+        super(ConfigTest, self).tearDown()
         shutil.rmtree(self.tmp_dir, True)
 
-    def check_config(self, comps):
-        config = spack.config.get_compilers_config()
-        compiler_list = ['cc', 'cxx', 'f77', 'f90']
-        for key in comps:
+
+    def check_config(self, comps, *compiler_names):
+        """Check that named compilers in comps match Spack's config."""
+        config = spack.config.get_config('compilers')
+        compiler_list = ['cc', 'cxx', 'f77', 'fc']
+        for key in compiler_names:
             for c in compiler_list:
-                if comps[key][c] == '/bad':
-                    continue
-                self.assertEqual(comps[key][c], config[key][c])
+                expected = comps['all'][key][c]
+                actual = config['all'][key][c]
+                self.assertEqual(expected, actual)
 
 
-    def test_write_key(self):
-        a_comps =  {"gcc@4.7.3" : { "cc" : "/gcc473", "cxx" : "/g++473", "f77" : None, "f90" : None },
-         "gcc@4.5.0" : { "cc" : "/gcc450", "cxx" : "/g++450", "f77" : "/gfortran", "f90" : "/gfortran" },
-         "clang@3.3"  : { "cc" : "/bad", "cxx" : "/bad", "f77" : "/bad", "f90" : "/bad" }}
+    def test_write_key_in_memory(self):
+        # Write b_comps "on top of" a_comps.
+        spack.config.update_config('compilers', a_comps, 'test_low_priority')
+        spack.config.update_config('compilers', b_comps, 'test_high_priority')
 
-        b_comps = {"icc@10.0" : { "cc" : "/icc100", "cxx" : "/icc100", "f77" : None, "f90" : None },
-         "icc@11.1" : { "cc" : "/icc111", "cxx" : "/icp111", "f77" : "/ifort", "f90" : "/ifort" },
-         "clang@3.3" : { "cc" : "/clang", "cxx" : "/clang++", "f77" :  None, "f90" : None}}
+        # Make sure the config looks how we expect.
+        self.check_config(a_comps, 'gcc@4.7.3', 'gcc@4.5.0')
+        self.check_config(b_comps, 'icc@10.0', 'icc@11.1', 'clang@3.3')
 
-        spack.config.add_to_compiler_config(a_comps, 'test_low_priority')
-        spack.config.add_to_compiler_config(b_comps, 'test_high_priority')
 
-        self.check_config(a_comps)
-        self.check_config(b_comps)
+    def test_write_key_to_disk(self):
+        # Write b_comps "on top of" a_comps.
+        spack.config.update_config('compilers', a_comps, 'test_low_priority')
+        spack.config.update_config('compilers', b_comps, 'test_high_priority')
 
+        # Clear caches so we're forced to read from disk.
         spack.config.clear_config_caches()
 
-        self.check_config(a_comps)
-        self.check_config(b_comps)
-
+        # Same check again, to ensure consistency.
+        self.check_config(a_comps, 'gcc@4.7.3', 'gcc@4.5.0')
+        self.check_config(b_comps, 'icc@10.0', 'icc@11.1', 'clang@3.3')
diff --git a/lib/spack/spack/test/database.py b/lib/spack/spack/test/database.py
index c07d32686e..0205f4b8ce 100644
--- a/lib/spack/spack/test/database.py
+++ b/lib/spack/spack/test/database.py
@@ -79,7 +79,8 @@ class DatabaseTest(MockPackagesTest):
 
     def _mock_install(self, spec):
         s = Spec(spec)
-        pkg = spack.db.get(s.concretized())
+        s.concretize()
+        pkg = spack.repo.get(s)
         pkg.do_install(fake=True)
 
 
diff --git a/lib/spack/spack/test/directory_layout.py b/lib/spack/spack/test/directory_layout.py
index 703ac1b867..925cb648ed 100644
--- a/lib/spack/spack/test/directory_layout.py
+++ b/lib/spack/spack/test/directory_layout.py
@@ -34,23 +34,27 @@ from llnl.util.filesystem import *
 
 import spack
 from spack.spec import Spec
-from spack.packages import PackageDB
+from spack.repository import RepoPath
 from spack.directory_layout import YamlDirectoryLayout
+from spack.test.mock_packages_test import *
+
 
 # number of packages to test (to reduce test time)
 max_packages = 10
 
 
-class DirectoryLayoutTest(unittest.TestCase):
+class DirectoryLayoutTest(MockPackagesTest):
     """Tests that a directory layout works correctly and produces a
        consistent install path."""
 
     def setUp(self):
+        super(DirectoryLayoutTest, self).setUp()
         self.tmpdir = tempfile.mkdtemp()
         self.layout = YamlDirectoryLayout(self.tmpdir)
 
 
     def tearDown(self):
+        super(DirectoryLayoutTest, self).tearDown()
         shutil.rmtree(self.tmpdir, ignore_errors=True)
         self.layout = None
 
@@ -62,7 +66,7 @@ class DirectoryLayoutTest(unittest.TestCase):
            finally that the directory can be removed by the directory
            layout.
         """
-        packages = list(spack.db.all_packages())[:max_packages]
+        packages = list(spack.repo.all_packages())[:max_packages]
 
         for pkg in packages:
             spec = pkg.spec
@@ -123,17 +127,17 @@ class DirectoryLayoutTest(unittest.TestCase):
            information about installed packages' specs to uninstall
            or query them again if the package goes away.
         """
-        mock_db = PackageDB(spack.mock_packages_path)
+        mock_db = RepoPath(spack.mock_packages_path)
 
         not_in_mock = set.difference(
-            set(spack.db.all_package_names()),
+            set(spack.repo.all_package_names()),
             set(mock_db.all_package_names()))
         packages = list(not_in_mock)[:max_packages]
 
         # Create all the packages that are not in mock.
         installed_specs = {}
         for pkg_name in packages:
-            spec = spack.db.get(pkg_name).spec
+            spec = spack.repo.get(pkg_name).spec
 
             # If a spec fails to concretize, just skip it.  If it is a
             # real error, it will be caught by concretization tests.
@@ -145,8 +149,7 @@ class DirectoryLayoutTest(unittest.TestCase):
             self.layout.create_install_directory(spec)
             installed_specs[spec] = self.layout.path_for_spec(spec)
 
-        tmp = spack.db
-        spack.db = mock_db
+        spack.repo.swap(mock_db)
 
         # Now check that even without the package files, we know
         # enough to read a spec from the spec file.
@@ -161,12 +164,12 @@ class DirectoryLayoutTest(unittest.TestCase):
             self.assertTrue(spec.eq_dag(spec_from_file))
             self.assertEqual(spec.dag_hash(), spec_from_file.dag_hash())
 
-        spack.db = tmp
+        spack.repo.swap(mock_db)
 
 
     def test_find(self):
         """Test that finding specs within an install layout works."""
-        packages = list(spack.db.all_packages())[:max_packages]
+        packages = list(spack.repo.all_packages())[:max_packages]
 
         # Create install prefixes for all packages in the list
         installed_specs = {}
diff --git a/lib/spack/spack/test/git_fetch.py b/lib/spack/spack/test/git_fetch.py
index 244680b5d0..3813079065 100644
--- a/lib/spack/spack/test/git_fetch.py
+++ b/lib/spack/spack/test/git_fetch.py
@@ -50,7 +50,7 @@ class GitFetchTest(MockPackagesTest):
 
         spec = Spec('git-test')
         spec.concretize()
-        self.pkg = spack.db.get(spec, new=True)
+        self.pkg = spack.repo.get(spec, new=True)
 
 
     def tearDown(self):
diff --git a/lib/spack/spack/test/hg_fetch.py b/lib/spack/spack/test/hg_fetch.py
index f8c6571bda..ee8327aec8 100644
--- a/lib/spack/spack/test/hg_fetch.py
+++ b/lib/spack/spack/test/hg_fetch.py
@@ -47,7 +47,7 @@ class HgFetchTest(MockPackagesTest):
 
         spec = Spec('hg-test')
         spec.concretize()
-        self.pkg = spack.db.get(spec, new=True)
+        self.pkg = spack.repo.get(spec, new=True)
 
 
     def tearDown(self):
diff --git a/lib/spack/spack/test/install.py b/lib/spack/spack/test/install.py
index 1ef4171fb2..628329a423 100644
--- a/lib/spack/spack/test/install.py
+++ b/lib/spack/spack/test/install.py
@@ -78,7 +78,7 @@ class InstallTest(MockPackagesTest):
         self.assertTrue(spec.concrete)
 
         # Get the package
-        pkg = spack.db.get(spec)
+        pkg = spack.repo.get(spec)
 
         # Fake the URL for the package so it downloads from a file.
         pkg.fetcher = URLFetchStrategy(self.repo.url)
diff --git a/lib/spack/spack/test/mirror.py b/lib/spack/spack/test/mirror.py
index 189a85fb1a..04e9e3db2e 100644
--- a/lib/spack/spack/test/mirror.py
+++ b/lib/spack/spack/test/mirror.py
@@ -55,7 +55,7 @@ class MirrorTest(MockPackagesTest):
         spec.concretize()
 
         # Get the package and fix its fetch args to point to a mock repo
-        pkg = spack.db.get(spec)
+        pkg = spack.repo.get(spec)
         repo = MockRepoClass()
         self.repos[name] = repo
 
diff --git a/lib/spack/spack/test/mock_packages_test.py b/lib/spack/spack/test/mock_packages_test.py
index e4e1b21b53..e9f1f95df5 100644
--- a/lib/spack/spack/test/mock_packages_test.py
+++ b/lib/spack/spack/test/mock_packages_test.py
@@ -22,43 +22,96 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
+import sys
+import os
+import shutil
 import unittest
+import tempfile
+from ordereddict_backport import OrderedDict
+
+from llnl.util.filesystem import mkdirp
 
 import spack
 import spack.config
-from spack.packages import PackageDB
+from spack.repository import RepoPath
 from spack.spec import Spec
 
-
-def set_pkg_dep(pkg, spec):
-    """Alters dependence information for a package.
-       Use this to mock up constraints.
-    """
-    spec = Spec(spec)
-    spack.db.get(pkg).dependencies[spec.name] = { Spec(pkg) : spec }
-
+mock_compiler_config = """\
+compilers:
+  all:
+    clang@3.3:
+      cc: /path/to/clang
+      cxx: /path/to/clang++
+      f77: None
+      fc: None
+    gcc@4.5.0:
+      cc: /path/to/gcc
+      cxx: /path/to/g++
+      f77: /path/to/gfortran
+      fc: /path/to/gfortran
+"""
 
 class MockPackagesTest(unittest.TestCase):
     def initmock(self):
         # Use the mock packages database for these tests.  This allows
         # us to set up contrived packages that don't interfere with
         # real ones.
-        self.real_db = spack.db
-        spack.db = PackageDB(spack.mock_packages_path)
+        self.db = RepoPath(spack.mock_packages_path)
+        spack.repo.swap(self.db)
 
         spack.config.clear_config_caches()
         self.real_scopes = spack.config.config_scopes
-        spack.config.config_scopes = [
-            ('site', spack.mock_site_config),
-            ('user', spack.mock_user_config)]
+
+        # Mock up temporary configuration directories
+        self.temp_config = tempfile.mkdtemp()
+        self.mock_site_config = os.path.join(self.temp_config, 'site')
+        self.mock_user_config = os.path.join(self.temp_config, 'user')
+        mkdirp(self.mock_site_config)
+        mkdirp(self.mock_user_config)
+        comp_yaml = os.path.join(self.mock_site_config, 'compilers.yaml')
+        with open(comp_yaml, 'w') as f:
+            f.write(mock_compiler_config)
+
+        # TODO: Mocking this up is kind of brittle b/c ConfigScope
+        # TODO: constructor modifies config_scopes.  Make it cleaner.
+        spack.config.config_scopes = OrderedDict()
+        spack.config.ConfigScope('site', self.mock_site_config)
+        spack.config.ConfigScope('user', self.mock_user_config)
+
+        # Store changes to the package's dependencies so we can
+        # restore later.
+        self.saved_deps = {}
+
+
+    def set_pkg_dep(self, pkg_name, spec):
+        """Alters dependence information for a package.
+
+        Adds a dependency on <spec> to pkg.
+        Use this to mock up constraints.
+        """
+        spec = Spec(spec)
+
+        # Save original dependencies before making any changes.
+        pkg = spack.repo.get(pkg_name)
+        if pkg_name not in self.saved_deps:
+            self.saved_deps[pkg_name] = (pkg, pkg.dependencies.copy())
+
+        # Change dep spec
+        pkg.dependencies[spec.name] = { Spec(pkg_name) : spec }
 
 
     def cleanmock(self):
         """Restore the real packages path after any test."""
-        spack.db = self.real_db
+        spack.repo.swap(self.db)
         spack.config.config_scopes = self.real_scopes
+        shutil.rmtree(self.temp_config, ignore_errors=True)
         spack.config.clear_config_caches()
 
+        # Restore dependency changes that happened during the test
+        for pkg_name, (pkg, deps) in self.saved_deps.items():
+            pkg.dependencies.clear()
+            pkg.dependencies.update(deps)
+
 
     def setUp(self):
         self.initmock()
@@ -66,5 +119,3 @@ class MockPackagesTest(unittest.TestCase):
 
     def tearDown(self):
         self.cleanmock()
-
-
diff --git a/lib/spack/spack/test/multimethod.py b/lib/spack/spack/test/multimethod.py
index d8d61d14c8..7bf4ff0a0a 100644
--- a/lib/spack/spack/test/multimethod.py
+++ b/lib/spack/spack/test/multimethod.py
@@ -38,92 +38,92 @@ from spack.test.mock_packages_test import *
 class MultiMethodTest(MockPackagesTest):
 
     def test_no_version_match(self):
-        pkg = spack.db.get('multimethod@2.0')
+        pkg = spack.repo.get('multimethod@2.0')
         self.assertRaises(NoSuchMethodError, pkg.no_version_2)
 
 
     def test_one_version_match(self):
-        pkg = spack.db.get('multimethod@1.0')
+        pkg = spack.repo.get('multimethod@1.0')
         self.assertEqual(pkg.no_version_2(), 1)
 
-        pkg = spack.db.get('multimethod@3.0')
+        pkg = spack.repo.get('multimethod@3.0')
         self.assertEqual(pkg.no_version_2(), 3)
 
-        pkg = spack.db.get('multimethod@4.0')
+        pkg = spack.repo.get('multimethod@4.0')
         self.assertEqual(pkg.no_version_2(), 4)
 
 
     def test_version_overlap(self):
-        pkg = spack.db.get('multimethod@2.0')
+        pkg = spack.repo.get('multimethod@2.0')
         self.assertEqual(pkg.version_overlap(), 1)
 
-        pkg = spack.db.get('multimethod@5.0')
+        pkg = spack.repo.get('multimethod@5.0')
         self.assertEqual(pkg.version_overlap(), 2)
 
 
     def test_mpi_version(self):
-        pkg = spack.db.get('multimethod^mpich@3.0.4')
+        pkg = spack.repo.get('multimethod^mpich@3.0.4')
         self.assertEqual(pkg.mpi_version(), 3)
 
-        pkg = spack.db.get('multimethod^mpich2@1.2')
+        pkg = spack.repo.get('multimethod^mpich2@1.2')
         self.assertEqual(pkg.mpi_version(), 2)
 
-        pkg = spack.db.get('multimethod^mpich@1.0')
+        pkg = spack.repo.get('multimethod^mpich@1.0')
         self.assertEqual(pkg.mpi_version(), 1)
 
 
     def test_undefined_mpi_version(self):
-        pkg = spack.db.get('multimethod^mpich@0.4')
+        pkg = spack.repo.get('multimethod^mpich@0.4')
         self.assertEqual(pkg.mpi_version(), 1)
 
-        pkg = spack.db.get('multimethod^mpich@1.4')
+        pkg = spack.repo.get('multimethod^mpich@1.4')
         self.assertEqual(pkg.mpi_version(), 1)
 
 
     def test_default_works(self):
-        pkg = spack.db.get('multimethod%gcc')
+        pkg = spack.repo.get('multimethod%gcc')
         self.assertEqual(pkg.has_a_default(), 'gcc')
 
-        pkg = spack.db.get('multimethod%intel')
+        pkg = spack.repo.get('multimethod%intel')
         self.assertEqual(pkg.has_a_default(), 'intel')
 
-        pkg = spack.db.get('multimethod%pgi')
+        pkg = spack.repo.get('multimethod%pgi')
         self.assertEqual(pkg.has_a_default(), 'default')
 
 
     def test_architecture_match(self):
-        pkg = spack.db.get('multimethod=x86_64')
+        pkg = spack.repo.get('multimethod=x86_64')
         self.assertEqual(pkg.different_by_architecture(), 'x86_64')
 
-        pkg = spack.db.get('multimethod=ppc64')
+        pkg = spack.repo.get('multimethod=ppc64')
         self.assertEqual(pkg.different_by_architecture(), 'ppc64')
 
-        pkg = spack.db.get('multimethod=ppc32')
+        pkg = spack.repo.get('multimethod=ppc32')
         self.assertEqual(pkg.different_by_architecture(), 'ppc32')
 
-        pkg = spack.db.get('multimethod=arm64')
+        pkg = spack.repo.get('multimethod=arm64')
         self.assertEqual(pkg.different_by_architecture(), 'arm64')
 
-        pkg = spack.db.get('multimethod=macos')
+        pkg = spack.repo.get('multimethod=macos')
         self.assertRaises(NoSuchMethodError, pkg.different_by_architecture)
 
 
     def test_dependency_match(self):
-        pkg = spack.db.get('multimethod^zmpi')
+        pkg = spack.repo.get('multimethod^zmpi')
         self.assertEqual(pkg.different_by_dep(), 'zmpi')
 
-        pkg = spack.db.get('multimethod^mpich')
+        pkg = spack.repo.get('multimethod^mpich')
         self.assertEqual(pkg.different_by_dep(), 'mpich')
 
         # If we try to switch on some entirely different dep, it's ambiguous,
         # but should take the first option
-        pkg = spack.db.get('multimethod^foobar')
+        pkg = spack.repo.get('multimethod^foobar')
         self.assertEqual(pkg.different_by_dep(), 'mpich')
 
 
     def test_virtual_dep_match(self):
-        pkg = spack.db.get('multimethod^mpich2')
+        pkg = spack.repo.get('multimethod^mpich2')
         self.assertEqual(pkg.different_by_virtual_dep(), 2)
 
-        pkg = spack.db.get('multimethod^mpich@1.0')
+        pkg = spack.repo.get('multimethod^mpich@1.0')
         self.assertEqual(pkg.different_by_virtual_dep(), 1)
diff --git a/lib/spack/spack/test/namespace_trie.py b/lib/spack/spack/test/namespace_trie.py
new file mode 100644
index 0000000000..d0d809004d
--- /dev/null
+++ b/lib/spack/spack/test/namespace_trie.py
@@ -0,0 +1,114 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import unittest
+from spack.util.naming import NamespaceTrie
+
+
+class NamespaceTrieTest(unittest.TestCase):
+
+    def setUp(self):
+        self.trie = NamespaceTrie()
+
+
+    def test_add_single(self):
+        self.trie['foo'] = 'bar'
+
+        self.assertTrue(self.trie.is_prefix('foo'))
+        self.assertTrue(self.trie.has_value('foo'))
+        self.assertEqual(self.trie['foo'], 'bar')
+
+
+    def test_add_multiple(self):
+        self.trie['foo.bar'] = 'baz'
+
+        self.assertFalse(self.trie.has_value('foo'))
+        self.assertTrue(self.trie.is_prefix('foo'))
+
+        self.assertTrue(self.trie.is_prefix('foo.bar'))
+        self.assertTrue(self.trie.has_value('foo.bar'))
+        self.assertEqual(self.trie['foo.bar'], 'baz')
+
+        self.assertFalse(self.trie.is_prefix('foo.bar.baz'))
+        self.assertFalse(self.trie.has_value('foo.bar.baz'))
+
+
+    def test_add_three(self):
+        # add a three-level namespace
+        self.trie['foo.bar.baz'] = 'quux'
+
+        self.assertTrue(self.trie.is_prefix('foo'))
+        self.assertFalse(self.trie.has_value('foo'))
+
+        self.assertTrue(self.trie.is_prefix('foo.bar'))
+        self.assertFalse(self.trie.has_value('foo.bar'))
+
+        self.assertTrue(self.trie.is_prefix('foo.bar.baz'))
+        self.assertTrue(self.trie.has_value('foo.bar.baz'))
+        self.assertEqual(self.trie['foo.bar.baz'], 'quux')
+
+        self.assertFalse(self.trie.is_prefix('foo.bar.baz.quux'))
+        self.assertFalse(self.trie.has_value('foo.bar.baz.quux'))
+
+        # Try to add a second element in a prefix namespace
+        self.trie['foo.bar'] = 'blah'
+
+        self.assertTrue(self.trie.is_prefix('foo'))
+        self.assertFalse(self.trie.has_value('foo'))
+
+        self.assertTrue(self.trie.is_prefix('foo.bar'))
+        self.assertTrue(self.trie.has_value('foo.bar'))
+        self.assertEqual(self.trie['foo.bar'], 'blah')
+
+        self.assertTrue(self.trie.is_prefix('foo.bar.baz'))
+        self.assertTrue(self.trie.has_value('foo.bar.baz'))
+        self.assertEqual(self.trie['foo.bar.baz'], 'quux')
+
+        self.assertFalse(self.trie.is_prefix('foo.bar.baz.quux'))
+        self.assertFalse(self.trie.has_value('foo.bar.baz.quux'))
+
+
+    def test_add_none_single(self):
+        self.trie['foo'] = None
+        self.assertTrue(self.trie.is_prefix('foo'))
+        self.assertTrue(self.trie.has_value('foo'))
+        self.assertEqual(self.trie['foo'], None)
+
+        self.assertFalse(self.trie.is_prefix('foo.bar'))
+        self.assertFalse(self.trie.has_value('foo.bar'))
+
+
+
+    def test_add_none_multiple(self):
+        self.trie['foo.bar'] = None
+
+        self.assertTrue(self.trie.is_prefix('foo'))
+        self.assertFalse(self.trie.has_value('foo'))
+
+        self.assertTrue(self.trie.is_prefix('foo.bar'))
+        self.assertTrue(self.trie.has_value('foo.bar'))
+        self.assertEqual(self.trie['foo.bar'], None)
+
+        self.assertFalse(self.trie.is_prefix('foo.bar.baz'))
+        self.assertFalse(self.trie.has_value('foo.bar.baz'))
diff --git a/lib/spack/spack/test/package_sanity.py b/lib/spack/spack/test/package_sanity.py
index 370cf676ef..ee09040d0d 100644
--- a/lib/spack/spack/test/package_sanity.py
+++ b/lib/spack/spack/test/package_sanity.py
@@ -28,16 +28,15 @@ This test does sanity checks on Spack's builtin package database.
 import unittest
 
 import spack
-import spack.url as url
-from spack.packages import PackageDB
+from spack.repository import RepoPath
 
 
 class PackageSanityTest(unittest.TestCase):
 
     def check_db(self):
         """Get all packages in a DB to make sure they work."""
-        for name in spack.db.all_package_names():
-            spack.db.get(name)
+        for name in spack.repo.all_package_names():
+            spack.repo.get(name)
 
 
     def test_get_all_packages(self):
@@ -47,15 +46,15 @@ class PackageSanityTest(unittest.TestCase):
 
     def test_get_all_mock_packages(self):
         """Get the mock packages once each too."""
-        tmp = spack.db
-        spack.db = PackageDB(spack.mock_packages_path)
+        db = RepoPath(spack.mock_packages_path)
+        spack.repo.swap(db)
         self.check_db()
-        spack.db = tmp
+        spack.repo.swap(db)
 
 
     def test_url_versions(self):
         """Check URLs for regular packages, if they are explicitly defined."""
-        for pkg in spack.db.all_packages():
+        for pkg in spack.repo.all_packages():
             for v, vattrs in pkg.versions.items():
                 if 'url' in vattrs:
                     # If there is a url for the version check it.
diff --git a/lib/spack/spack/test/packages.py b/lib/spack/spack/test/packages.py
index b2daea7b7b..83984dc5f6 100644
--- a/lib/spack/spack/test/packages.py
+++ b/lib/spack/spack/test/packages.py
@@ -27,7 +27,7 @@ import unittest
 from llnl.util.filesystem import join_path
 
 import spack
-import spack.packages as packages
+from spack.repository import Repo
 from spack.util.naming import mod_to_class
 from spack.test.mock_packages_test import *
 
@@ -35,27 +35,32 @@ from spack.test.mock_packages_test import *
 class PackagesTest(MockPackagesTest):
 
     def test_load_package(self):
-        pkg = spack.db.get('mpich')
+        pkg = spack.repo.get('mpich')
 
 
     def test_package_name(self):
-        pkg = spack.db.get('mpich')
+        pkg = spack.repo.get('mpich')
         self.assertEqual(pkg.name, 'mpich')
 
 
     def test_package_filename(self):
-        filename = spack.db.filename_for_package_name('mpich')
-        self.assertEqual(filename, join_path(spack.mock_packages_path, 'mpich', 'package.py'))
+        repo = Repo(spack.mock_packages_path)
+        filename = repo.filename_for_package_name('mpich')
+        self.assertEqual(filename,
+                         join_path(spack.mock_packages_path, 'packages', 'mpich', 'package.py'))
 
 
     def test_package_name(self):
-        pkg = spack.db.get('mpich')
+        pkg = spack.repo.get('mpich')
         self.assertEqual(pkg.name, 'mpich')
 
 
     def test_nonexisting_package_filename(self):
-        filename = spack.db.filename_for_package_name('some-nonexisting-package')
-        self.assertEqual(filename, join_path(spack.mock_packages_path, 'some-nonexisting-package', 'package.py'))
+        repo = Repo(spack.mock_packages_path)
+        filename = repo.filename_for_package_name('some-nonexisting-package')
+        self.assertEqual(
+            filename,
+            join_path(spack.mock_packages_path, 'packages', 'some-nonexisting-package', 'package.py'))
 
 
     def test_package_class_names(self):
@@ -64,3 +69,38 @@ class PackagesTest(MockPackagesTest):
         self.assertEqual('PmgrCollective', mod_to_class('pmgr-collective'))
         self.assertEqual('Pmgrcollective', mod_to_class('PmgrCollective'))
         self.assertEqual('_3db',        mod_to_class('3db'))
+
+
+    #
+    # Below tests target direct imports of spack packages from the
+    # spack.pkg namespace
+    #
+
+    def test_import_package(self):
+        import spack.pkg.builtin.mock.mpich
+
+
+    def test_import_package_as(self):
+        import spack.pkg.builtin.mock.mpich as mp
+
+
+    def test_import_class_from_package(self):
+        from spack.pkg.builtin.mock.mpich import Mpich
+
+
+    def test_import_module_from_package(self):
+        from spack.pkg.builtin.mock import mpich
+
+
+    def test_import_namespace_container_modules(self):
+        import spack.pkg
+        import spack.pkg as p
+        from spack import pkg
+
+        import spack.pkg.builtin
+        import spack.pkg.builtin as b
+        from spack.pkg import builtin
+
+        import spack.pkg.builtin.mock
+        import spack.pkg.builtin.mock as m
+        from spack.pkg.builtin import mock
diff --git a/lib/spack/spack/test/python_version.py b/lib/spack/spack/test/python_version.py
index 2ea5febb11..d74d3b9b7d 100644
--- a/lib/spack/spack/test/python_version.py
+++ b/lib/spack/spack/test/python_version.py
@@ -54,8 +54,8 @@ class PythonVersionTest(unittest.TestCase):
 
 
     def package_py_files(self):
-        for name in spack.db.all_package_names():
-            yield spack.db.filename_for_package_name(name)
+        for name in spack.repo.all_package_names():
+            yield spack.repo.filename_for_package_name(name)
 
 
     def check_python_versions(self, *files):
diff --git a/lib/spack/spack/test/spec_dag.py b/lib/spack/spack/test/spec_dag.py
index d3a4d77b32..632f777cde 100644
--- a/lib/spack/spack/test/spec_dag.py
+++ b/lib/spack/spack/test/spec_dag.py
@@ -40,8 +40,8 @@ from spack.test.mock_packages_test import *
 class SpecDagTest(MockPackagesTest):
 
     def test_conflicting_package_constraints(self):
-        set_pkg_dep('mpileaks', 'mpich@1.0')
-        set_pkg_dep('callpath', 'mpich@2.0')
+        self.set_pkg_dep('mpileaks', 'mpich@1.0')
+        self.set_pkg_dep('callpath', 'mpich@2.0')
 
         spec = Spec('mpileaks ^mpich ^callpath ^dyninst ^libelf ^libdwarf')
 
@@ -223,25 +223,25 @@ class SpecDagTest(MockPackagesTest):
 
 
     def test_unsatisfiable_version(self):
-        set_pkg_dep('mpileaks', 'mpich@1.0')
+        self.set_pkg_dep('mpileaks', 'mpich@1.0')
         spec = Spec('mpileaks ^mpich@2.0 ^callpath ^dyninst ^libelf ^libdwarf')
         self.assertRaises(spack.spec.UnsatisfiableVersionSpecError, spec.normalize)
 
 
     def test_unsatisfiable_compiler(self):
-        set_pkg_dep('mpileaks', 'mpich%gcc')
+        self.set_pkg_dep('mpileaks', 'mpich%gcc')
         spec = Spec('mpileaks ^mpich%intel ^callpath ^dyninst ^libelf ^libdwarf')
         self.assertRaises(spack.spec.UnsatisfiableCompilerSpecError, spec.normalize)
 
 
     def test_unsatisfiable_compiler_version(self):
-        set_pkg_dep('mpileaks', 'mpich%gcc@4.6')
+        self.set_pkg_dep('mpileaks', 'mpich%gcc@4.6')
         spec = Spec('mpileaks ^mpich%gcc@4.5 ^callpath ^dyninst ^libelf ^libdwarf')
         self.assertRaises(spack.spec.UnsatisfiableCompilerSpecError, spec.normalize)
 
 
     def test_unsatisfiable_architecture(self):
-        set_pkg_dep('mpileaks', 'mpich=bgqos_0')
+        self.set_pkg_dep('mpileaks', 'mpich=bgqos_0')
         spec = Spec('mpileaks ^mpich=sles_10_ppc64 ^callpath ^dyninst ^libelf ^libdwarf')
         self.assertRaises(spack.spec.UnsatisfiableArchitectureSpecError, spec.normalize)
 
diff --git a/lib/spack/spack/test/spec_semantics.py b/lib/spack/spack/test/spec_semantics.py
index 1381556aad..44a09cbd7f 100644
--- a/lib/spack/spack/test/spec_semantics.py
+++ b/lib/spack/spack/test/spec_semantics.py
@@ -35,7 +35,10 @@ class SpecSematicsTest(MockPackagesTest):
     # ================================================================================
     def check_satisfies(self, spec, anon_spec, concrete=False):
         left = Spec(spec, concrete=concrete)
-        right = parse_anonymous_spec(anon_spec, left.name)
+        try:
+            right = Spec(anon_spec)  # if it's not anonymous, allow it.
+        except:
+            right = parse_anonymous_spec(anon_spec, left.name)
 
         # Satisfies is one-directional.
         self.assertTrue(left.satisfies(right))
@@ -48,7 +51,10 @@ class SpecSematicsTest(MockPackagesTest):
 
     def check_unsatisfiable(self, spec, anon_spec, concrete=False):
         left = Spec(spec, concrete=concrete)
-        right = parse_anonymous_spec(anon_spec, left.name)
+        try:
+            right = Spec(anon_spec)  # if it's not anonymous, allow it.
+        except:
+            right = parse_anonymous_spec(anon_spec, left.name)
 
         self.assertFalse(left.satisfies(right))
         self.assertFalse(left.satisfies(anon_spec))
@@ -88,6 +94,28 @@ class SpecSematicsTest(MockPackagesTest):
         self.check_satisfies('libdwarf^libelf@0.8.13', '^libelf@0:1')
 
 
+    def test_satisfies_namespace(self):
+        self.check_satisfies('builtin.mpich', 'mpich')
+        self.check_satisfies('builtin.mock.mpich', 'mpich')
+
+        # TODO: only works for deps now, but shouldn't we allow this for root spec?
+        # self.check_satisfies('builtin.mock.mpich', 'mpi')
+
+        self.check_satisfies('builtin.mock.mpich', 'builtin.mock.mpich')
+
+        self.check_unsatisfiable('builtin.mock.mpich', 'builtin.mpich')
+
+
+    def test_satisfies_namespaced_dep(self):
+        """Ensure spec from same or unspecified namespace satisfies namespace constraint."""
+        self.check_satisfies('mpileaks ^builtin.mock.mpich', '^mpich')
+
+        self.check_satisfies('mpileaks ^builtin.mock.mpich', '^mpi')
+        self.check_satisfies('mpileaks ^builtin.mock.mpich', '^builtin.mock.mpich')
+
+        self.check_unsatisfiable('mpileaks ^builtin.mock.mpich', '^builtin.mpich')
+
+
     def test_satisfies_compiler(self):
         self.check_satisfies('foo%gcc', '%gcc')
         self.check_satisfies('foo%intel', '%intel')
diff --git a/lib/spack/spack/test/svn_fetch.py b/lib/spack/spack/test/svn_fetch.py
index 9229af76d4..2ee4748fdb 100644
--- a/lib/spack/spack/test/svn_fetch.py
+++ b/lib/spack/spack/test/svn_fetch.py
@@ -49,7 +49,7 @@ class SvnFetchTest(MockPackagesTest):
 
         spec = Spec('svn-test')
         spec.concretize()
-        self.pkg = spack.db.get(spec, new=True)
+        self.pkg = spack.repo.get(spec, new=True)
 
 
     def tearDown(self):
diff --git a/lib/spack/spack/test/unit_install.py b/lib/spack/spack/test/unit_install.py
index 864d5a1765..ccc409dd60 100644
--- a/lib/spack/spack/test/unit_install.py
+++ b/lib/spack/spack/test/unit_install.py
@@ -26,16 +26,16 @@ import unittest
 import itertools
 
 import spack
-test_install = __import__("spack.cmd.test-install", 
+test_install = __import__("spack.cmd.test-install",
     fromlist=["BuildId", "create_test_output", "TestResult"])
 
 class MockOutput(object):
     def __init__(self):
         self.results = {}
-    
+
     def add_test(self, buildId, passed=True, buildInfo=None):
         self.results[buildId] = passed
-    
+
     def write_to(self, stream):
         pass
 
@@ -45,14 +45,14 @@ class MockSpec(object):
         self.name = name
         self.version = version
         self.hash = hashStr if hashStr else hash((name, version))
-    
+
     def traverse(self, order=None):
-        allDeps = itertools.chain.from_iterable(i.traverse() for i in 
+        allDeps = itertools.chain.from_iterable(i.traverse() for i in
             self.dependencies.itervalues())
         return set(itertools.chain([self], allDeps))
-    
+
     def dag_hash(self):
-        return self.hash 
+        return self.hash
 
     def to_yaml(self):
         return "<<<MOCK YAML {0}>>>".format(test_install.BuildId(self).stringId())
@@ -75,47 +75,51 @@ class UnitInstallTest(unittest.TestCase):
 
     def setUp(self):
         super(UnitInstallTest, self).setUp()
-        
+
         pkgX.installed = False
         pkgY.installed = False
 
+        self.saved_db = spack.repo
         pkgDb = MockPackageDb({specX:pkgX, specY:pkgY})
-        spack.db = pkgDb
+        spack.repo = pkgDb
+
 
     def tearDown(self):
         super(UnitInstallTest, self).tearDown()
-        
+
+        spack.repo = self.saved_db
+
     def test_installing_both(self):
         mo = MockOutput()
-        
+
         pkgX.installed = True
         pkgY.installed = True
         test_install.create_test_output(specX, [specX, specY], mo, getLogFunc=mock_fetch_log)
-        
-        self.assertEqual(mo.results, 
-            {bIdX:test_install.TestResult.PASSED, 
-            bIdY:test_install.TestResult.PASSED})
+
+        self.assertEqual(mo.results,
+            {bIdX:test_install.TestResult.PASSED,
+             bIdY:test_install.TestResult.PASSED})
+
 
     def test_dependency_already_installed(self):
         mo = MockOutput()
-        
+
         pkgX.installed = True
         pkgY.installed = True
         test_install.create_test_output(specX, [specX], mo, getLogFunc=mock_fetch_log)
-        
         self.assertEqual(mo.results, {bIdX:test_install.TestResult.PASSED})
 
     #TODO: add test(s) where Y fails to install
 
+
 class MockPackageDb(object):
     def __init__(self, init=None):
         self.specToPkg = {}
         if init:
             self.specToPkg.update(init)
-        
+
     def get(self, spec):
         return self.specToPkg[spec]
 
 def mock_fetch_log(path):
     return []
-
diff --git a/lib/spack/spack/test/url_substitution.py b/lib/spack/spack/test/url_substitution.py
index 8b90ee086a..aec8baf4ea 100644
--- a/lib/spack/spack/test/url_substitution.py
+++ b/lib/spack/spack/test/url_substitution.py
@@ -29,7 +29,6 @@ import unittest
 
 import spack
 import spack.url as url
-from spack.packages import PackageDB
 
 
 class PackageSanityTest(unittest.TestCase):
diff --git a/lib/spack/spack/test/yaml.py b/lib/spack/spack/test/yaml.py
new file mode 100644
index 0000000000..5a357b8e69
--- /dev/null
+++ b/lib/spack/spack/test/yaml.py
@@ -0,0 +1,93 @@
+##############################################################################
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+"""
+Test Spack's custom YAML format.
+"""
+import unittest
+import spack.util.spack_yaml as syaml
+
+test_file = """\
+config_file:
+  x86_64:
+    foo: /path/to/foo
+    bar: /path/to/bar
+    baz: /path/to/baz
+  some_list:
+    - item 1
+    - item 2
+    - item 3
+  another_list:
+    [ 1, 2, 3 ]
+  some_key: some_string
+"""
+
+test_data = {
+    'config_file' : syaml.syaml_dict([
+        ('x86_64', syaml.syaml_dict([
+            ('foo', '/path/to/foo'),
+            ('bar', '/path/to/bar'),
+            ('baz', '/path/to/baz' )])),
+        ('some_list', [ 'item 1', 'item 2', 'item 3' ]),
+        ('another_list', [ 1, 2, 3 ]),
+        ('some_key', 'some_string')
+    ])}
+
+class YamlTest(unittest.TestCase):
+
+    def setUp(self):
+        self.data = syaml.load(test_file)
+
+
+    def test_parse(self):
+        self.assertEqual(test_data, self.data)
+
+
+    def test_dict_order(self):
+        self.assertEqual(
+            ['x86_64', 'some_list', 'another_list', 'some_key'],
+            self.data['config_file'].keys())
+
+        self.assertEqual(
+            ['foo', 'bar', 'baz'],
+            self.data['config_file']['x86_64'].keys())
+
+
+    def test_line_numbers(self):
+        def check(obj, start_line, end_line):
+            self.assertEqual(obj._start_mark.line, start_line)
+            self.assertEqual(obj._end_mark.line, end_line)
+
+        check(self.data,                                  0, 12)
+        check(self.data['config_file'],                   1, 12)
+        check(self.data['config_file']['x86_64'],         2,  5)
+        check(self.data['config_file']['x86_64']['foo'],  2,  2)
+        check(self.data['config_file']['x86_64']['bar'],  3,  3)
+        check(self.data['config_file']['x86_64']['baz'],  4,  4)
+        check(self.data['config_file']['some_list'],      6,  9)
+        check(self.data['config_file']['some_list'][0],   6,  6)
+        check(self.data['config_file']['some_list'][1],   7,  7)
+        check(self.data['config_file']['some_list'][2],   8,  8)
+        check(self.data['config_file']['another_list'],  10, 10)
+        check(self.data['config_file']['some_key'],      11, 11)
diff --git a/lib/spack/spack/util/naming.py b/lib/spack/spack/util/naming.py
index 782afbd4bb..5025f15027 100644
--- a/lib/spack/spack/util/naming.py
+++ b/lib/spack/spack/util/naming.py
@@ -1,13 +1,22 @@
 # Need this because of spack.util.string
 from __future__ import absolute_import
 import string
+import itertools
 import re
+from StringIO import StringIO
 
 import spack
 
+__all__ = ['mod_to_class', 'spack_module_to_python_module', 'valid_module_name',
+           'valid_fully_qualified_module_name', 'validate_fully_qualified_module_name',
+           'validate_module_name', 'possible_spack_module_names', 'NamespaceTrie']
+
 # Valid module names can contain '-' but can't start with it.
 _valid_module_re = r'^\w[\w-]*$'
 
+# Valid module names can contain '-' but can't start with it.
+_valid_fully_qualified_module_re = r'^(\w[\w-]*)(\.\w[\w-]*)*$'
+
 
 def mod_to_class(mod_name):
     """Convert a name from module style to class name style.  Spack mostly
@@ -42,20 +51,160 @@ def mod_to_class(mod_name):
     return class_name
 
 
+def spack_module_to_python_module(mod_name):
+    """Given a Spack module name, returns the name by which it can be
+       imported in Python.
+    """
+    if re.match(r'[0-9]', mod_name):
+        mod_name = 'num' + mod_name
+
+    return mod_name.replace('-', '_')
+
+
+def possible_spack_module_names(python_mod_name):
+    """Given a Python module name, return a list of all possible spack module
+       names that could correspond to it."""
+    mod_name = re.sub(r'^num(\d)', r'\1', python_mod_name)
+
+    parts = re.split(r'(_)', mod_name)
+    options = [['_', '-']] * mod_name.count('_')
+
+    results = []
+    for subs in itertools.product(*options):
+        s = list(parts)
+        s[1::2] = subs
+        results.append(''.join(s))
+
+    return results
+
+
 def valid_module_name(mod_name):
-    """Return whether the mod_name is valid for use in Spack."""
+    """Return whether mod_name is valid for use in Spack."""
     return bool(re.match(_valid_module_re, mod_name))
 
 
+def valid_fully_qualified_module_name(mod_name):
+    """Return whether mod_name is a valid namespaced module name."""
+    return bool(re.match(_valid_fully_qualified_module_re, mod_name))
+
+
 def validate_module_name(mod_name):
     """Raise an exception if mod_name is not valid."""
     if not valid_module_name(mod_name):
         raise InvalidModuleNameError(mod_name)
 
 
+def validate_fully_qualified_module_name(mod_name):
+    """Raise an exception if mod_name is not a valid namespaced module name."""
+    if not valid_fully_qualified_module_name(mod_name):
+        raise InvalidFullyQualifiedModuleNameError(mod_name)
+
+
 class InvalidModuleNameError(spack.error.SpackError):
     """Raised when we encounter a bad module name."""
     def __init__(self, name):
         super(InvalidModuleNameError, self).__init__(
             "Invalid module name: " + name)
         self.name = name
+
+
+class InvalidFullyQualifiedModuleNameError(spack.error.SpackError):
+    """Raised when we encounter a bad full package name."""
+    def __init__(self, name):
+        super(InvalidFullyQualifiedModuleNameError, self).__init__(
+            "Invalid fully qualified package name: " + name)
+        self.name = name
+
+
+class NamespaceTrie(object):
+    class Element(object):
+        def __init__(self, value):
+            self.value = value
+
+
+    def __init__(self, separator='.'):
+        self._subspaces = {}
+        self._value = None
+        self._sep = separator
+
+
+    def __setitem__(self, namespace, value):
+        first, sep, rest = namespace.partition(self._sep)
+
+        if not first:
+            self._value = NamespaceTrie.Element(value)
+            return
+
+        if first not in self._subspaces:
+            self._subspaces[first] = NamespaceTrie()
+
+        self._subspaces[first][rest] = value
+
+
+    def _get_helper(self, namespace, full_name):
+        first, sep, rest = namespace.partition(self._sep)
+        if not first:
+            if not self._value:
+                raise KeyError("Can't find namespace '%s' in trie" % full_name)
+            return self._value.value
+        elif first not in self._subspaces:
+            raise KeyError("Can't find namespace '%s' in trie" % full_name)
+        else:
+            return self._subspaces[first]._get_helper(rest, full_name)
+
+
+    def __getitem__(self, namespace):
+        return self._get_helper(namespace, namespace)
+
+
+    def is_prefix(self, namespace):
+        """True if the namespace has a value, or if it's the prefix of one that does."""
+        first, sep, rest = namespace.partition(self._sep)
+        if not first:
+            return True
+        elif first not in self._subspaces:
+            return False
+        else:
+            return self._subspaces[first].is_prefix(rest)
+
+
+    def is_leaf(self, namespace):
+        """True if this namespace has no children in the trie."""
+        first, sep, rest = namespace.partition(self._sep)
+        if not first:
+            return bool(self._subspaces)
+        elif first not in self._subspaces:
+            return False
+        else:
+            return self._subspaces[first].is_leaf(rest)
+
+
+    def has_value(self, namespace):
+        """True if there is a value set for the given namespace."""
+        first, sep, rest = namespace.partition(self._sep)
+        if not first:
+            return self._value is not None
+        elif first not in self._subspaces:
+            return False
+        else:
+            return self._subspaces[first].has_value(rest)
+
+
+    def __contains__(self, namespace):
+        """Returns whether a value has been set for the namespace."""
+        return self.has_value(namespace)
+
+
+    def _str_helper(self, stream, level=0):
+        indent = (level * '    ')
+        for name in sorted(self._subspaces):
+            stream.write(indent + name + '\n')
+            if self._value:
+                stream.write(indent + '  ' + repr(self._value.value))
+            stream.write(self._subspaces[name]._str_helper(stream, level+1))
+
+
+    def __str__(self):
+        stream = StringIO()
+        self._str_helper(stream)
+        return stream.getvalue()
diff --git a/lib/spack/spack/util/spack_yaml.py b/lib/spack/spack/util/spack_yaml.py
new file mode 100644
index 0000000000..728e86b8ee
--- /dev/null
+++ b/lib/spack/spack/util/spack_yaml.py
@@ -0,0 +1,201 @@
+##############################################################################
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+"""Enhanced YAML parsing for Spack.
+
+- ``load()`` preserves YAML Marks on returned objects -- this allows
+  us to access file and line information later.
+
+- ``Our load methods use ``OrderedDict`` class instead of YAML's
+  default unorderd dict.
+
+"""
+import yaml
+from yaml.nodes import *
+from yaml.constructor import ConstructorError
+from yaml.representer import SafeRepresenter
+from ordereddict_backport import OrderedDict
+
+# Only export load and dump
+__all__ = ['load', 'dump']
+
+# Make new classes so we can add custom attributes.
+# Also, use OrderedDict instead of just dict.
+class syaml_dict(OrderedDict):
+    def __repr__(self):
+        mappings = ('%r: %r' % (k,v) for k,v in self.items())
+        return '{%s}' % ', '.join(mappings)
+class syaml_list(list):
+    __repr__ = list.__repr__
+class syaml_str(str):
+    __repr__ = str.__repr__
+
+def mark(obj, node):
+    """Add start and end markers to an object."""
+    obj._start_mark = node.start_mark
+    obj._end_mark = node.end_mark
+
+
+class OrderedLineLoader(yaml.Loader):
+    """YAML loader that preserves order and line numbers.
+
+       Mappings read in by this loader behave like an ordered dict.
+       Sequences, mappings, and strings also have new attributes,
+       ``_start_mark`` and ``_end_mark``, that preserve YAML line
+       information in the output data.
+
+    """
+    #
+    # Override construct_yaml_* so that they build our derived types,
+    # which allows us to add new attributes to them.
+    #
+    # The standard YAML constructors return empty instances and fill
+    # in with mappings later.  We preserve this behavior.
+    #
+    def construct_yaml_str(self, node):
+        value = self.construct_scalar(node)
+        try:
+            value = value.encode('ascii')
+        except UnicodeEncodeError:
+            pass
+        value = syaml_str(value)
+        mark(value, node)
+        return value
+
+
+    def construct_yaml_seq(self, node):
+        data = syaml_list()
+        mark(data, node)
+        yield data
+        data.extend(self.construct_sequence(node))
+
+
+    def construct_yaml_map(self, node):
+        data = syaml_dict()
+        mark(data, node)
+        yield data
+        value = self.construct_mapping(node)
+        data.update(value)
+
+    #
+    # Override the ``construct_*`` routines. These fill in empty
+    # objects after yielded by the above ``construct_yaml_*`` methods.
+    #
+    def construct_sequence(self, node, deep=False):
+        if not isinstance(node, SequenceNode):
+            raise ConstructorError(None, None,
+                    "expected a sequence node, but found %s" % node.id,
+                    node.start_mark)
+        value =  syaml_list(self.construct_object(child, deep=deep)
+                             for child in node.value)
+        mark(value, node)
+        return value
+
+
+    def construct_mapping(self, node, deep=False):
+        """Store mappings as OrderedDicts instead of as regular python
+           dictionaries to preserve file ordering."""
+        if not isinstance(node, MappingNode):
+            raise ConstructorError(None, None,
+                    "expected a mapping node, but found %s" % node.id,
+                    node.start_mark)
+
+        mapping = syaml_dict()
+        for key_node, value_node in node.value:
+            key = self.construct_object(key_node, deep=deep)
+            try:
+                hash(key)
+            except TypeError, exc:
+                raise ConstructorError("while constructing a mapping", node.start_mark,
+                        "found unacceptable key (%s)" % exc, key_node.start_mark)
+            value = self.construct_object(value_node, deep=deep)
+            if key in mapping:
+                raise ConstructorError("while constructing a mapping", node.start_mark,
+                                       "found already in-use key (%s)" % key, key_node.start_mark)
+            mapping[key] = value
+
+        mark(mapping, node)
+        return mapping
+
+# register above new constructors
+OrderedLineLoader.add_constructor(u'tag:yaml.org,2002:map', OrderedLineLoader.construct_yaml_map)
+OrderedLineLoader.add_constructor(u'tag:yaml.org,2002:seq', OrderedLineLoader.construct_yaml_seq)
+OrderedLineLoader.add_constructor(u'tag:yaml.org,2002:str', OrderedLineLoader.construct_yaml_str)
+
+
+
+class OrderedLineDumper(yaml.Dumper):
+    """Dumper that preserves ordering and formats ``syaml_*`` objects.
+
+      This dumper preserves insertion ordering ``syaml_dict`` objects
+      when they're written out.  It also has some custom formatters
+      for ``syaml_*`` objects so that they are formatted like their
+      regular Python equivalents, instead of ugly YAML pyobjects.
+
+    """
+    def represent_mapping(self, tag, mapping, flow_style=None):
+        value = []
+        node = MappingNode(tag, value, flow_style=flow_style)
+        if self.alias_key is not None:
+            self.represented_objects[self.alias_key] = node
+        best_style = True
+        if hasattr(mapping, 'items'):
+            # if it's a syaml_dict, preserve OrderedDict order.
+            # Otherwise do the default thing.
+            sort = not isinstance(mapping, syaml_dict)
+            mapping = mapping.items()
+            if sort:
+                mapping.sort()
+
+        for item_key, item_value in mapping:
+            node_key = self.represent_data(item_key)
+            node_value = self.represent_data(item_value)
+            if not (isinstance(node_key, ScalarNode) and not node_key.style):
+                best_style = False
+            if not (isinstance(node_value, ScalarNode) and not node_value.style):
+                best_style = False
+            value.append((node_key, node_value))
+        if flow_style is None:
+            if self.default_flow_style is not None:
+                node.flow_style = self.default_flow_style
+            else:
+                node.flow_style = best_style
+        return node
+
+# Make our special objects look like normal YAML ones.
+OrderedLineDumper.add_representer(syaml_dict, OrderedLineDumper.represent_dict)
+OrderedLineDumper.add_representer(syaml_list, OrderedLineDumper.represent_list)
+OrderedLineDumper.add_representer(syaml_str, OrderedLineDumper.represent_str)
+
+
+def load(*args, **kwargs):
+    """Load but modify the loader instance so that it will add __line__
+       atrributes to the returned object."""
+    kwargs['Loader'] = OrderedLineLoader
+    return yaml.load(*args, **kwargs)
+
+
+def dump(*args, **kwargs):
+    kwargs['Dumper'] = OrderedLineDumper
+    return yaml.dump(*args, **kwargs)