Merge branch 'features/yaml-spec' into features/optional-deps

lib/spack/external/__init__.py

@@ -28,6 +28,11 @@
 
 So far:
     argparse:    We include our own version to be Python 2.6 compatible.
-    pyqver2:     External script to query required python version of python source code.
-                 Used for ensuring 2.6 compatibility.
+
+    pyqver2:     External script to query required python version of
+                 python source code. Used for ensuring 2.6 compatibility.
+
+    functools:   Used for implementation of total_ordering.
+
+    yaml:        Used for config files.
 """

lib/spack/external/yaml/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2006 Kirill Simonov
+
+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.

lib/spack/external/yaml/README

@@ -0,0 +1,35 @@
+PyYAML - The next generation YAML parser and emitter for Python.
+
+To install, type 'python setup.py install'.
+
+By default, the setup.py script checks whether LibYAML is installed
+and if so, builds and installs LibYAML bindings.  To skip the check
+and force installation of LibYAML bindings, use the option '--with-libyaml':
+'python setup.py --with-libyaml install'.  To disable the check and
+skip building and installing LibYAML bindings, use '--without-libyaml':
+'python setup.py --without-libyaml install'.
+
+When LibYAML bindings are installed, you may use fast LibYAML-based
+parser and emitter as follows:
+
+    >>> yaml.load(stream, Loader=yaml.CLoader)
+    >>> yaml.dump(data, Dumper=yaml.CDumper)
+
+PyYAML includes a comprehensive test suite.  To run the tests,
+type 'python setup.py test'.
+
+For more information, check the PyYAML homepage:
+'http://pyyaml.org/wiki/PyYAML'.
+
+For PyYAML tutorial and reference, see:
+'http://pyyaml.org/wiki/PyYAMLDocumentation'.
+
+Post your questions and opinions to the YAML-Core mailing list:
+'http://lists.sourceforge.net/lists/listinfo/yaml-core'.
+
+Submit bug reports and feature requests to the PyYAML bug tracker:
+'http://pyyaml.org/newticket?component=pyyaml'.
+
+PyYAML is written by Kirill Simonov <xi@resolvent.net>.  It is released
+under the MIT license. See the file LICENSE for more details.
+

lib/spack/external/yaml/__init__.py

@@ -0,0 +1,315 @@
+
+from error import *
+
+from tokens import *
+from events import *
+from nodes import *
+
+from loader import *
+from dumper import *
+
+__version__ = '3.10'
+
+try:
+    from cyaml import *
+    __with_libyaml__ = True
+except ImportError:
+    __with_libyaml__ = False
+
+def scan(stream, Loader=Loader):
+    """
+    Scan a YAML stream and produce scanning tokens.
+    """
+    loader = Loader(stream)
+    try:
+        while loader.check_token():
+            yield loader.get_token()
+    finally:
+        loader.dispose()
+
+def parse(stream, Loader=Loader):
+    """
+    Parse a YAML stream and produce parsing events.
+    """
+    loader = Loader(stream)
+    try:
+        while loader.check_event():
+            yield loader.get_event()
+    finally:
+        loader.dispose()
+
+def compose(stream, Loader=Loader):
+    """
+    Parse the first YAML document in a stream
+    and produce the corresponding representation tree.
+    """
+    loader = Loader(stream)
+    try:
+        return loader.get_single_node()
+    finally:
+        loader.dispose()
+
+def compose_all(stream, Loader=Loader):
+    """
+    Parse all YAML documents in a stream
+    and produce corresponding representation trees.
+    """
+    loader = Loader(stream)
+    try:
+        while loader.check_node():
+            yield loader.get_node()
+    finally:
+        loader.dispose()
+
+def load(stream, Loader=Loader):
+    """
+    Parse the first YAML document in a stream
+    and produce the corresponding Python object.
+    """
+    loader = Loader(stream)
+    try:
+        return loader.get_single_data()
+    finally:
+        loader.dispose()
+
+def load_all(stream, Loader=Loader):
+    """
+    Parse all YAML documents in a stream
+    and produce corresponding Python objects.
+    """
+    loader = Loader(stream)
+    try:
+        while loader.check_data():
+            yield loader.get_data()
+    finally:
+        loader.dispose()
+
+def safe_load(stream):
+    """
+    Parse the first YAML document in a stream
+    and produce the corresponding Python object.
+    Resolve only basic YAML tags.
+    """
+    return load(stream, SafeLoader)
+
+def safe_load_all(stream):
+    """
+    Parse all YAML documents in a stream
+    and produce corresponding Python objects.
+    Resolve only basic YAML tags.
+    """
+    return load_all(stream, SafeLoader)
+
+def emit(events, stream=None, Dumper=Dumper,
+        canonical=None, indent=None, width=None,
+        allow_unicode=None, line_break=None):
+    """
+    Emit YAML parsing events into a stream.
+    If stream is None, return the produced string instead.
+    """
+    getvalue = None
+    if stream is None:
+        from StringIO import StringIO
+        stream = StringIO()
+        getvalue = stream.getvalue
+    dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
+            allow_unicode=allow_unicode, line_break=line_break)
+    try:
+        for event in events:
+            dumper.emit(event)
+    finally:
+        dumper.dispose()
+    if getvalue:
+        return getvalue()
+
+def serialize_all(nodes, stream=None, Dumper=Dumper,
+        canonical=None, indent=None, width=None,
+        allow_unicode=None, line_break=None,
+        encoding='utf-8', explicit_start=None, explicit_end=None,
+        version=None, tags=None):
+    """
+    Serialize a sequence of representation trees into a YAML stream.
+    If stream is None, return the produced string instead.
+    """
+    getvalue = None
+    if stream is None:
+        if encoding is None:
+            from StringIO import StringIO
+        else:
+            from cStringIO import StringIO
+        stream = StringIO()
+        getvalue = stream.getvalue
+    dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
+            allow_unicode=allow_unicode, line_break=line_break,
+            encoding=encoding, version=version, tags=tags,
+            explicit_start=explicit_start, explicit_end=explicit_end)
+    try:
+        dumper.open()
+        for node in nodes:
+            dumper.serialize(node)
+        dumper.close()
+    finally:
+        dumper.dispose()
+    if getvalue:
+        return getvalue()
+
+def serialize(node, stream=None, Dumper=Dumper, **kwds):
+    """
+    Serialize a representation tree into a YAML stream.
+    If stream is None, return the produced string instead.
+    """
+    return serialize_all([node], stream, Dumper=Dumper, **kwds)
+
+def dump_all(documents, stream=None, Dumper=Dumper,
+        default_style=None, default_flow_style=None,
+        canonical=None, indent=None, width=None,
+        allow_unicode=None, line_break=None,
+        encoding='utf-8', explicit_start=None, explicit_end=None,
+        version=None, tags=None):
+    """
+    Serialize a sequence of Python objects into a YAML stream.
+    If stream is None, return the produced string instead.
+    """
+    getvalue = None
+    if stream is None:
+        if encoding is None:
+            from StringIO import StringIO
+        else:
+            from cStringIO import StringIO
+        stream = StringIO()
+        getvalue = stream.getvalue
+    dumper = Dumper(stream, default_style=default_style,
+            default_flow_style=default_flow_style,
+            canonical=canonical, indent=indent, width=width,
+            allow_unicode=allow_unicode, line_break=line_break,
+            encoding=encoding, version=version, tags=tags,
+            explicit_start=explicit_start, explicit_end=explicit_end)
+    try:
+        dumper.open()
+        for data in documents:
+            dumper.represent(data)
+        dumper.close()
+    finally:
+        dumper.dispose()
+    if getvalue:
+        return getvalue()
+
+def dump(data, stream=None, Dumper=Dumper, **kwds):
+    """
+    Serialize a Python object into a YAML stream.
+    If stream is None, return the produced string instead.
+    """
+    return dump_all([data], stream, Dumper=Dumper, **kwds)
+
+def safe_dump_all(documents, stream=None, **kwds):
+    """
+    Serialize a sequence of Python objects into a YAML stream.
+    Produce only basic YAML tags.
+    If stream is None, return the produced string instead.
+    """
+    return dump_all(documents, stream, Dumper=SafeDumper, **kwds)
+
+def safe_dump(data, stream=None, **kwds):
+    """
+    Serialize a Python object into a YAML stream.
+    Produce only basic YAML tags.
+    If stream is None, return the produced string instead.
+    """
+    return dump_all([data], stream, Dumper=SafeDumper, **kwds)
+
+def add_implicit_resolver(tag, regexp, first=None,
+        Loader=Loader, Dumper=Dumper):
+    """
+    Add an implicit scalar detector.
+    If an implicit scalar value matches the given regexp,
+    the corresponding tag is assigned to the scalar.
+    first is a sequence of possible initial characters or None.
+    """
+    Loader.add_implicit_resolver(tag, regexp, first)
+    Dumper.add_implicit_resolver(tag, regexp, first)
+
+def add_path_resolver(tag, path, kind=None, Loader=Loader, Dumper=Dumper):
+    """
+    Add a path based resolver for the given tag.
+    A path is a list of keys that forms a path
+    to a node in the representation tree.
+    Keys can be string values, integers, or None.
+    """
+    Loader.add_path_resolver(tag, path, kind)
+    Dumper.add_path_resolver(tag, path, kind)
+
+def add_constructor(tag, constructor, Loader=Loader):
+    """
+    Add a constructor for the given tag.
+    Constructor is a function that accepts a Loader instance
+    and a node object and produces the corresponding Python object.
+    """
+    Loader.add_constructor(tag, constructor)
+
+def add_multi_constructor(tag_prefix, multi_constructor, Loader=Loader):
+    """
+    Add a multi-constructor for the given tag prefix.
+    Multi-constructor is called for a node if its tag starts with tag_prefix.
+    Multi-constructor accepts a Loader instance, a tag suffix,
+    and a node object and produces the corresponding Python object.
+    """
+    Loader.add_multi_constructor(tag_prefix, multi_constructor)
+
+def add_representer(data_type, representer, Dumper=Dumper):
+    """
+    Add a representer for the given type.
+    Representer is a function accepting a Dumper instance
+    and an instance of the given data type
+    and producing the corresponding representation node.
+    """
+    Dumper.add_representer(data_type, representer)
+
+def add_multi_representer(data_type, multi_representer, Dumper=Dumper):
+    """
+    Add a representer for the given type.
+    Multi-representer is a function accepting a Dumper instance
+    and an instance of the given data type or subtype
+    and producing the corresponding representation node.
+    """
+    Dumper.add_multi_representer(data_type, multi_representer)
+
+class YAMLObjectMetaclass(type):
+    """
+    The metaclass for YAMLObject.
+    """
+    def __init__(cls, name, bases, kwds):
+        super(YAMLObjectMetaclass, cls).__init__(name, bases, kwds)
+        if 'yaml_tag' in kwds and kwds['yaml_tag'] is not None:
+            cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
+            cls.yaml_dumper.add_representer(cls, cls.to_yaml)
+
+class YAMLObject(object):
+    """
+    An object that can dump itself to a YAML stream
+    and load itself from a YAML stream.
+    """
+
+    __metaclass__ = YAMLObjectMetaclass
+    __slots__ = ()  # no direct instantiation, so allow immutable subclasses
+
+    yaml_loader = Loader
+    yaml_dumper = Dumper
+
+    yaml_tag = None
+    yaml_flow_style = None
+
+    def from_yaml(cls, loader, node):
+        """
+        Convert a representation node to a Python object.
+        """
+        return loader.construct_yaml_object(node, cls)
+    from_yaml = classmethod(from_yaml)
+
+    def to_yaml(cls, dumper, data):
+        """
+        Convert a Python object to a representation node.
+        """
+        return dumper.represent_yaml_object(cls.yaml_tag, data, cls,
+                flow_style=cls.yaml_flow_style)
+    to_yaml = classmethod(to_yaml)
+

lib/spack/external/yaml/composer.py

@@ -0,0 +1,139 @@
+
+__all__ = ['Composer', 'ComposerError']
+
+from error import MarkedYAMLError
+from events import *
+from nodes import *
+
+class ComposerError(MarkedYAMLError):
+    pass
+
+class Composer(object):
+
+    def __init__(self):
+        self.anchors = {}
+
+    def check_node(self):
+        # Drop the STREAM-START event.
+        if self.check_event(StreamStartEvent):
+            self.get_event()
+
+        # If there are more documents available?
+        return not self.check_event(StreamEndEvent)
+
+    def get_node(self):
+        # Get the root node of the next document.
+        if not self.check_event(StreamEndEvent):
+            return self.compose_document()
+
+    def get_single_node(self):
+        # Drop the STREAM-START event.
+        self.get_event()
+
+        # Compose a document if the stream is not empty.
+        document = None
+        if not self.check_event(StreamEndEvent):
+            document = self.compose_document()
+
+        # Ensure that the stream contains no more documents.
+        if not self.check_event(StreamEndEvent):
+            event = self.get_event()
+            raise ComposerError("expected a single document in the stream",
+                    document.start_mark, "but found another document",
+                    event.start_mark)
+
+        # Drop the STREAM-END event.
+        self.get_event()
+
+        return document
+
+    def compose_document(self):
+        # Drop the DOCUMENT-START event.
+        self.get_event()
+
+        # Compose the root node.
+        node = self.compose_node(None, None)
+
+        # Drop the DOCUMENT-END event.
+        self.get_event()
+
+        self.anchors = {}
+        return node
+
+    def compose_node(self, parent, index):
+        if self.check_event(AliasEvent):
+            event = self.get_event()
+            anchor = event.anchor
+            if anchor not in self.anchors:
+                raise ComposerError(None, None, "found undefined alias %r"
+                        % anchor.encode('utf-8'), event.start_mark)
+            return self.anchors[anchor]
+        event = self.peek_event()
+        anchor = event.anchor
+        if anchor is not None:
+            if anchor in self.anchors:
+                raise ComposerError("found duplicate anchor %r; first occurence"
+                        % anchor.encode('utf-8'), self.anchors[anchor].start_mark,
+                        "second occurence", event.start_mark)
+        self.descend_resolver(parent, index)
+        if self.check_event(ScalarEvent):
+            node = self.compose_scalar_node(anchor)
+        elif self.check_event(SequenceStartEvent):
+            node = self.compose_sequence_node(anchor)
+        elif self.check_event(MappingStartEvent):
+            node = self.compose_mapping_node(anchor)
+        self.ascend_resolver()
+        return node
+
+    def compose_scalar_node(self, anchor):
+        event = self.get_event()
+        tag = event.tag
+        if tag is None or tag == u'!':
+            tag = self.resolve(ScalarNode, event.value, event.implicit)
+        node = ScalarNode(tag, event.value,
+                event.start_mark, event.end_mark, style=event.style)
+        if anchor is not None:
+            self.anchors[anchor] = node
+        return node
+
+    def compose_sequence_node(self, anchor):
+        start_event = self.get_event()
+        tag = start_event.tag
+        if tag is None or tag == u'!':
+            tag = self.resolve(SequenceNode, None, start_event.implicit)
+        node = SequenceNode(tag, [],
+                start_event.start_mark, None,
+                flow_style=start_event.flow_style)
+        if anchor is not None:
+            self.anchors[anchor] = node
+        index = 0
+        while not self.check_event(SequenceEndEvent):
+            node.value.append(self.compose_node(node, index))
+            index += 1
+        end_event = self.get_event()
+        node.end_mark = end_event.end_mark
+        return node
+
+    def compose_mapping_node(self, anchor):
+        start_event = self.get_event()
+        tag = start_event.tag
+        if tag is None or tag == u'!':
+            tag = self.resolve(MappingNode, None, start_event.implicit)
+        node = MappingNode(tag, [],
+                start_event.start_mark, None,
+                flow_style=start_event.flow_style)
+        if anchor is not None:
+            self.anchors[anchor] = node
+        while not self.check_event(MappingEndEvent):
+            #key_event = self.peek_event()
+            item_key = self.compose_node(node, None)
+            #if item_key in node.value:
+            #    raise ComposerError("while composing a mapping", start_event.start_mark,
+            #            "found duplicate key", key_event.start_mark)
+            item_value = self.compose_node(node, item_key)
+            #node.value[item_key] = item_value
+            node.value.append((item_key, item_value))
+        end_event = self.get_event()
+        node.end_mark = end_event.end_mark
+        return node
+

lib/spack/external/yaml/constructor.py

@@ -0,0 +1,678 @@
+
+__all__ = ['BaseConstructor', 'SafeConstructor', 'Constructor',
+    'ConstructorError']
+
+from error import *
+from nodes import *
+
+import datetime
+
+import binascii, re, sys, types
+
+class ConstructorError(MarkedYAMLError):
+    pass
+
+class BaseConstructor(object):
+
+    yaml_constructors = {}
+    yaml_multi_constructors = {}
+
+    def __init__(self):
+        self.constructed_objects = {}
+        self.recursive_objects = {}
+        self.state_generators = []
+        self.deep_construct = False
+
+    def check_data(self):
+        # If there are more documents available?
+        return self.check_node()
+
+    def get_data(self):
+        # Construct and return the next document.
+        if self.check_node():
+            return self.construct_document(self.get_node())
+
+    def get_single_data(self):
+        # Ensure that the stream contains a single document and construct it.
+        node = self.get_single_node()
+        if node is not None:
+            return self.construct_document(node)
+        return None
+
+    def construct_document(self, node):
+        data = self.construct_object(node)
+        while self.state_generators:
+            state_generators = self.state_generators
+            self.state_generators = []
+            for generator in state_generators:
+                for dummy in generator:
+                    pass
+        self.constructed_objects = {}
+        self.recursive_objects = {}
+        self.deep_construct = False
+        return data
+
+    def construct_object(self, node, deep=False):
+        if node in self.constructed_objects:
+            return self.constructed_objects[node]
+        if deep:
+            old_deep = self.deep_construct
+            self.deep_construct = True
+        if node in self.recursive_objects:
+            raise ConstructorError(None, None,
+                    "found unconstructable recursive node", node.start_mark)
+        self.recursive_objects[node] = None
+        constructor = None
+        tag_suffix = None
+        if node.tag in self.yaml_constructors:
+            constructor = self.yaml_constructors[node.tag]
+        else:
+            for tag_prefix in self.yaml_multi_constructors:
+                if node.tag.startswith(tag_prefix):
+                    tag_suffix = node.tag[len(tag_prefix):]
+                    constructor = self.yaml_multi_constructors[tag_prefix]
+                    break
+            else:
+                if None in self.yaml_multi_constructors:
+                    tag_suffix = node.tag
+                    constructor = self.yaml_multi_constructors[None]
+                elif None in self.yaml_constructors:
+                    constructor = self.yaml_constructors[None]
+                elif isinstance(node, ScalarNode):
+                    constructor = self.__class__.construct_scalar
+                elif isinstance(node, SequenceNode):
+                    constructor = self.__class__.construct_sequence
+                elif isinstance(node, MappingNode):
+                    constructor = self.__class__.construct_mapping
+        if tag_suffix is None:
+            data = constructor(self, node)
+        else:
+            data = constructor(self, tag_suffix, node)
+        if isinstance(data, types.GeneratorType):
+            generator = data
+            data = generator.next()
+            if self.deep_construct:
+                for dummy in generator:
+                    pass
+            else:
+                self.state_generators.append(generator)
+        self.constructed_objects[node] = data
+        del self.recursive_objects[node]
+        if deep:
+            self.deep_construct = old_deep
+        return data
+
+    def construct_scalar(self, node):
+        if not isinstance(node, ScalarNode):
+            raise ConstructorError(None, None,
+                    "expected a scalar node, but found %s" % node.id,
+                    node.start_mark)
+        return node.value
+
+    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)
+        return [self.construct_object(child, deep=deep)
+                for child in node.value]
+
+    def construct_mapping(self, node, deep=False):
+        if not isinstance(node, MappingNode):
+            raise ConstructorError(None, None,
+                    "expected a mapping node, but found %s" % node.id,
+                    node.start_mark)
+        mapping = {}
+        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
+        return mapping
+
+    def construct_pairs(self, node, deep=False):
+        if not isinstance(node, MappingNode):
+            raise ConstructorError(None, None,
+                    "expected a mapping node, but found %s" % node.id,
+                    node.start_mark)
+        pairs = []
+        for key_node, value_node in node.value:
+            key = self.construct_object(key_node, deep=deep)
+            value = self.construct_object(value_node, deep=deep)
+            pairs.append((key, value))
+        return pairs
+
+    def add_constructor(cls, tag, constructor):
+        if not 'yaml_constructors' in cls.__dict__:
+            cls.yaml_constructors = cls.yaml_constructors.copy()
+        cls.yaml_constructors[tag] = constructor
+    add_constructor = classmethod(add_constructor)
+
+    def add_multi_constructor(cls, tag_prefix, multi_constructor):
+        if not 'yaml_multi_constructors' in cls.__dict__:
+            cls.yaml_multi_constructors = cls.yaml_multi_constructors.copy()
+        cls.yaml_multi_constructors[tag_prefix] = multi_constructor
+    add_multi_constructor = classmethod(add_multi_constructor)
+
+class SafeConstructor(BaseConstructor):
+
+    def construct_scalar(self, node):
+        if isinstance(node, MappingNode):
+            for key_node, value_node in node.value:
+                if key_node.tag == u'tag:yaml.org,2002:value':
+                    return self.construct_scalar(value_node)
+        return BaseConstructor.construct_scalar(self, node)
+
+    def flatten_mapping(self, node):
+        merge = []
+        index = 0
+        while index < len(node.value):
+            key_node, value_node = node.value[index]
+            if key_node.tag == u'tag:yaml.org,2002:merge':
+                del node.value[index]
+                if isinstance(value_node, MappingNode):
+                    self.flatten_mapping(value_node)
+                    merge.extend(value_node.value)
+                elif isinstance(value_node, SequenceNode):
+                    submerge = []
+                    for subnode in value_node.value:
+                        if not isinstance(subnode, MappingNode):
+                            raise ConstructorError("while constructing a mapping",
+                                    node.start_mark,
+                                    "expected a mapping for merging, but found %s"
+                                    % subnode.id, subnode.start_mark)
+                        self.flatten_mapping(subnode)
+                        submerge.append(subnode.value)
+                    submerge.reverse()
+                    for value in submerge:
+                        merge.extend(value)
+                else:
+                    raise ConstructorError("while constructing a mapping", node.start_mark,
+                            "expected a mapping or list of mappings for merging, but found %s"
+                            % value_node.id, value_node.start_mark)
+            elif key_node.tag == u'tag:yaml.org,2002:value':
+                key_node.tag = u'tag:yaml.org,2002:str'
+                index += 1
+            else:
+                index += 1
+        if merge:
+            node.value = merge + node.value
+
+    def construct_mapping(self, node, deep=False):
+        if isinstance(node, MappingNode):
+            self.flatten_mapping(node)
+        return BaseConstructor.construct_mapping(self, node, deep=deep)
+
+    def construct_yaml_null(self, node):
+        self.construct_scalar(node)
+        return None
+
+    bool_values = {
+        u'yes':     True,
+        u'no':      False,
+        u'true':    True,
+        u'false':   False,
+        u'on':      True,
+        u'off':     False,
+    }
+
+    def construct_yaml_bool(self, node):
+        value = self.construct_scalar(node)
+        return self.bool_values[value.lower()]
+
+    def construct_yaml_int(self, node):
+        value = str(self.construct_scalar(node))
+        value = value.replace('_', '')
+        sign = +1
+        if value[0] == '-':
+            sign = -1
+        if value[0] in '+-':
+            value = value[1:]
+        if value == '0':
+            return 0
+        elif value.startswith('0b'):
+            return sign*int(value[2:], 2)
+        elif value.startswith('0x'):
+            return sign*int(value[2:], 16)
+        elif value[0] == '0':
+            return sign*int(value, 8)
+        elif ':' in value:
+            digits = [int(part) for part in value.split(':')]
+            digits.reverse()
+            base = 1
+            value = 0
+            for digit in digits:
+                value += digit*base
+                base *= 60
+            return sign*value
+        else:
+            return sign*int(value)
+
+    inf_value = 1e300
+    while inf_value != inf_value*inf_value:
+        inf_value *= inf_value
+    nan_value = -inf_value/inf_value   # Trying to make a quiet NaN (like C99).
+
+    def construct_yaml_float(self, node):
+        value = str(self.construct_scalar(node))
+        value = value.replace('_', '').lower()
+        sign = +1
+        if value[0] == '-':
+            sign = -1
+        if value[0] in '+-':
+            value = value[1:]
+        if value == '.inf':
+            return sign*self.inf_value
+        elif value == '.nan':
+            return self.nan_value
+        elif ':' in value:
+            digits = [float(part) for part in value.split(':')]
+            digits.reverse()
+            base = 1
+            value = 0.0
+            for digit in digits:
+                value += digit*base
+                base *= 60
+            return sign*value
+        else:
+            return sign*float(value)
+
+    def construct_yaml_binary(self, node):
+        value = self.construct_scalar(node)
+        try:
+            return str(value).decode('base64')
+        except (binascii.Error, UnicodeEncodeError), exc:
+            raise ConstructorError(None, None,
+                    "failed to decode base64 data: %s" % exc, node.start_mark) 
+
+    timestamp_regexp = re.compile(
+            ur'''^(?P<year>[0-9][0-9][0-9][0-9])
+                -(?P<month>[0-9][0-9]?)
+                -(?P<day>[0-9][0-9]?)
+                (?:(?:[Tt]|[ \t]+)
+                (?P<hour>[0-9][0-9]?)
+                :(?P<minute>[0-9][0-9])
+                :(?P<second>[0-9][0-9])
+                (?:\.(?P<fraction>[0-9]*))?
+                (?:[ \t]*(?P<tz>Z|(?P<tz_sign>[-+])(?P<tz_hour>[0-9][0-9]?)
+                (?::(?P<tz_minute>[0-9][0-9]))?))?)?$''', re.X)
+
+    def construct_yaml_timestamp(self, node):
+        value = self.construct_scalar(node)
+        match = self.timestamp_regexp.match(node.value)
+        values = match.groupdict()
+        year = int(values['year'])
+        month = int(values['month'])
+        day = int(values['day'])
+        if not values['hour']:
+            return datetime.date(year, month, day)
+        hour = int(values['hour'])
+        minute = int(values['minute'])
+        second = int(values['second'])
+        fraction = 0
+        if values['fraction']:
+            fraction = values['fraction'][:6]
+            while len(fraction) < 6:
+                fraction += '0'
+            fraction = int(fraction)
+        delta = None
+        if values['tz_sign']:
+            tz_hour = int(values['tz_hour'])
+            tz_minute = int(values['tz_minute'] or 0)
+            delta = datetime.timedelta(hours=tz_hour, minutes=tz_minute)
+            if values['tz_sign'] == '-':
+                delta = -delta
+        data = datetime.datetime(year, month, day, hour, minute, second, fraction)
+        if delta:
+            data -= delta
+        return data
+
+    def construct_yaml_omap(self, node):
+        # Note: we do not check for duplicate keys, because it's too
+        # CPU-expensive.
+        omap = []
+        yield omap
+        if not isinstance(node, SequenceNode):
+            raise ConstructorError("while constructing an ordered map", node.start_mark,
+                    "expected a sequence, but found %s" % node.id, node.start_mark)
+        for subnode in node.value:
+            if not isinstance(subnode, MappingNode):
+                raise ConstructorError("while constructing an ordered map", node.start_mark,
+                        "expected a mapping of length 1, but found %s" % subnode.id,
+                        subnode.start_mark)
+            if len(subnode.value) != 1:
+                raise ConstructorError("while constructing an ordered map", node.start_mark,
+                        "expected a single mapping item, but found %d items" % len(subnode.value),
+                        subnode.start_mark)
+            key_node, value_node = subnode.value[0]
+            key = self.construct_object(key_node)
+            value = self.construct_object(value_node)
+            omap.append((key, value))
+
+    def construct_yaml_pairs(self, node):
+        # Note: the same code as `construct_yaml_omap`.
+        pairs = []
+        yield pairs
+        if not isinstance(node, SequenceNode):
+            raise ConstructorError("while constructing pairs", node.start_mark,
+                    "expected a sequence, but found %s" % node.id, node.start_mark)
+        for subnode in node.value:
+            if not isinstance(subnode, MappingNode):
+                raise ConstructorError("while constructing pairs", node.start_mark,
+                        "expected a mapping of length 1, but found %s" % subnode.id,
+                        subnode.start_mark)
+            if len(subnode.value) != 1:
+                raise ConstructorError("while constructing pairs", node.start_mark,
+                        "expected a single mapping item, but found %d items" % len(subnode.value),
+                        subnode.start_mark)
+            key_node, value_node = subnode.value[0]
+            key = self.construct_object(key_node)
+            value = self.construct_object(value_node)
+            pairs.append((key, value))
+
+    def construct_yaml_set(self, node):
+        data = set()
+        yield data
+        value = self.construct_mapping(node)
+        data.update(value)
+
+    def construct_yaml_str(self, node):
+        value = self.construct_scalar(node)
+        try:
+            return value.encode('ascii')
+        except UnicodeEncodeError:
+            return value
+
+    def construct_yaml_seq(self, node):
+        data = []
+        yield data
+        data.extend(self.construct_sequence(node))
+
+    def construct_yaml_map(self, node):
+        data = {}
+        yield data
+        value = self.construct_mapping(node)
+        data.update(value)
+
+    def construct_yaml_object(self, node, cls):
+        data = cls.__new__(cls)
+        yield data
+        if hasattr(data, '__setstate__'):
+            state = self.construct_mapping(node, deep=True)
+            data.__setstate__(state)
+        else:
+            state = self.construct_mapping(node)
+            data.__dict__.update(state)
+
+    def construct_undefined(self, node):
+        raise ConstructorError(None, None,
+                "could not determine a constructor for the tag %r" % node.tag.encode('utf-8'),
+                node.start_mark)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:null',
+        SafeConstructor.construct_yaml_null)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:bool',
+        SafeConstructor.construct_yaml_bool)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:int',
+        SafeConstructor.construct_yaml_int)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:float',
+        SafeConstructor.construct_yaml_float)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:binary',
+        SafeConstructor.construct_yaml_binary)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:timestamp',
+        SafeConstructor.construct_yaml_timestamp)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:omap',
+        SafeConstructor.construct_yaml_omap)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:pairs',
+        SafeConstructor.construct_yaml_pairs)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:set',
+        SafeConstructor.construct_yaml_set)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:str',
+        SafeConstructor.construct_yaml_str)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:seq',
+        SafeConstructor.construct_yaml_seq)
+
+SafeConstructor.add_constructor(
+        u'tag:yaml.org,2002:map',
+        SafeConstructor.construct_yaml_map)
+
+SafeConstructor.add_constructor(None,
+        SafeConstructor.construct_undefined)
+
+class Constructor(SafeConstructor):
+
+    def construct_python_str(self, node):
+        return self.construct_scalar(node).encode('utf-8')
+
+    def construct_python_unicode(self, node):
+        return self.construct_scalar(node)
+
+    def construct_python_long(self, node):
+        return long(self.construct_yaml_int(node))
+
+    def construct_python_complex(self, node):
+       return complex(self.construct_scalar(node))
+
+    def construct_python_tuple(self, node):
+        return tuple(self.construct_sequence(node))
+
+    def find_python_module(self, name, mark):
+        if not name:
+            raise ConstructorError("while constructing a Python module", mark,
+                    "expected non-empty name appended to the tag", mark)
+        try:
+            __import__(name)
+        except ImportError, exc:
+            raise ConstructorError("while constructing a Python module", mark,
+                    "cannot find module %r (%s)" % (name.encode('utf-8'), exc), mark)
+        return sys.modules[name]
+
+    def find_python_name(self, name, mark):
+        if not name:
+            raise ConstructorError("while constructing a Python object", mark,
+                    "expected non-empty name appended to the tag", mark)
+        if u'.' in name:
+            module_name, object_name = name.rsplit('.', 1)
+        else:
+            module_name = '__builtin__'
+            object_name = name
+        try:
+            __import__(module_name)
+        except ImportError, exc:
+            raise ConstructorError("while constructing a Python object", mark,
+                    "cannot find module %r (%s)" % (module_name.encode('utf-8'), exc), mark)
+        module = sys.modules[module_name]
+        if not hasattr(module, object_name):
+            raise ConstructorError("while constructing a Python object", mark,
+                    "cannot find %r in the module %r" % (object_name.encode('utf-8'),
+                        module.__name__), mark)
+        return getattr(module, object_name)
+
+    def construct_python_name(self, suffix, node):
+        value = self.construct_scalar(node)
+        if value:
+            raise ConstructorError("while constructing a Python name", node.start_mark,
+                    "expected the empty value, but found %r" % value.encode('utf-8'),
+                    node.start_mark)
+        return self.find_python_name(suffix, node.start_mark)
+
+    def construct_python_module(self, suffix, node):
+        value = self.construct_scalar(node)
+        if value:
+            raise ConstructorError("while constructing a Python module", node.start_mark,
+                    "expected the empty value, but found %r" % value.encode('utf-8'),
+                    node.start_mark)
+        return self.find_python_module(suffix, node.start_mark)
+
+    class classobj: pass
+
+    def make_python_instance(self, suffix, node,
+            args=None, kwds=None, newobj=False):
+        if not args:
+            args = []
+        if not kwds:
+            kwds = {}
+        cls = self.find_python_name(suffix, node.start_mark)
+        if newobj and isinstance(cls, type(self.classobj))  \
+                and not args and not kwds:
+            instance = self.classobj()
+            instance.__class__ = cls
+            return instance
+        elif newobj and isinstance(cls, type):
+            return cls.__new__(cls, *args, **kwds)
+        else:
+            return cls(*args, **kwds)
+
+    def set_python_instance_state(self, instance, state):
+        if hasattr(instance, '__setstate__'):
+            instance.__setstate__(state)
+        else:
+            slotstate = {}
+            if isinstance(state, tuple) and len(state) == 2:
+                state, slotstate = state
+            if hasattr(instance, '__dict__'):
+                instance.__dict__.update(state)
+            elif state:
+                slotstate.update(state)
+            for key, value in slotstate.items():
+                setattr(object, key, value)
+
+    def construct_python_object(self, suffix, node):
+        # Format:
+        #   !!python/object:module.name { ... state ... }
+        instance = self.make_python_instance(suffix, node, newobj=True)
+        yield instance
+        deep = hasattr(instance, '__setstate__')
+        state = self.construct_mapping(node, deep=deep)
+        self.set_python_instance_state(instance, state)
+
+    def construct_python_object_apply(self, suffix, node, newobj=False):
+        # Format:
+        #   !!python/object/apply       # (or !!python/object/new)
+        #   args: [ ... arguments ... ]
+        #   kwds: { ... keywords ... }
+        #   state: ... state ...
+        #   listitems: [ ... listitems ... ]
+        #   dictitems: { ... dictitems ... }
+        # or short format:
+        #   !!python/object/apply [ ... arguments ... ]
+        # The difference between !!python/object/apply and !!python/object/new
+        # is how an object is created, check make_python_instance for details.
+        if isinstance(node, SequenceNode):
+            args = self.construct_sequence(node, deep=True)
+            kwds = {}
+            state = {}
+            listitems = []
+            dictitems = {}
+        else:
+            value = self.construct_mapping(node, deep=True)
+            args = value.get('args', [])
+            kwds = value.get('kwds', {})
+            state = value.get('state', {})
+            listitems = value.get('listitems', [])
+            dictitems = value.get('dictitems', {})
+        instance = self.make_python_instance(suffix, node, args, kwds, newobj)
+        if state:
+            self.set_python_instance_state(instance, state)
+        if listitems:
+            instance.extend(listitems)
+        if dictitems:
+            for key in dictitems:
+                instance[key] = dictitems[key]
+        return instance
+
+    def construct_python_object_new(self, suffix, node):
+        return self.construct_python_object_apply(suffix, node, newobj=True)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/none',
+    Constructor.construct_yaml_null)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/bool',
+    Constructor.construct_yaml_bool)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/str',
+    Constructor.construct_python_str)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/unicode',
+    Constructor.construct_python_unicode)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/int',
+    Constructor.construct_yaml_int)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/long',
+    Constructor.construct_python_long)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/float',
+    Constructor.construct_yaml_float)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/complex',
+    Constructor.construct_python_complex)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/list',
+    Constructor.construct_yaml_seq)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/tuple',
+    Constructor.construct_python_tuple)
+
+Constructor.add_constructor(
+    u'tag:yaml.org,2002:python/dict',
+    Constructor.construct_yaml_map)
+
+Constructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/name:',
+    Constructor.construct_python_name)
+
+Constructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/module:',
+    Constructor.construct_python_module)
+
+Constructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/object:',
+    Constructor.construct_python_object)
+
+Constructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/object/apply:',
+    Constructor.construct_python_object_apply)
+
+Constructor.add_multi_constructor(
+    u'tag:yaml.org,2002:python/object/new:',
+    Constructor.construct_python_object_new)
+

lib/spack/external/yaml/dumper.py

@@ -0,0 +1,62 @@
+
+__all__ = ['BaseDumper', 'SafeDumper', 'Dumper']
+
+from emitter import *
+from serializer import *
+from representer import *
+from resolver import *
+
+class BaseDumper(Emitter, Serializer, BaseRepresenter, BaseResolver):
+
+    def __init__(self, stream,
+            default_style=None, default_flow_style=None,
+            canonical=None, indent=None, width=None,
+            allow_unicode=None, line_break=None,
+            encoding=None, explicit_start=None, explicit_end=None,
+            version=None, tags=None):
+        Emitter.__init__(self, stream, canonical=canonical,
+                indent=indent, width=width,
+                allow_unicode=allow_unicode, line_break=line_break)
+        Serializer.__init__(self, encoding=encoding,
+                explicit_start=explicit_start, explicit_end=explicit_end,
+                version=version, tags=tags)
+        Representer.__init__(self, default_style=default_style,
+                default_flow_style=default_flow_style)
+        Resolver.__init__(self)
+
+class SafeDumper(Emitter, Serializer, SafeRepresenter, Resolver):
+
+    def __init__(self, stream,
+            default_style=None, default_flow_style=None,
+            canonical=None, indent=None, width=None,
+            allow_unicode=None, line_break=None,
+            encoding=None, explicit_start=None, explicit_end=None,
+            version=None, tags=None):
+        Emitter.__init__(self, stream, canonical=canonical,
+                indent=indent, width=width,
+                allow_unicode=allow_unicode, line_break=line_break)
+        Serializer.__init__(self, encoding=encoding,
+                explicit_start=explicit_start, explicit_end=explicit_end,
+                version=version, tags=tags)
+        SafeRepresenter.__init__(self, default_style=default_style,
+                default_flow_style=default_flow_style)
+        Resolver.__init__(self)
+
+class Dumper(Emitter, Serializer, Representer, Resolver):
+
+    def __init__(self, stream,
+            default_style=None, default_flow_style=None,
+            canonical=None, indent=None, width=None,
+            allow_unicode=None, line_break=None,
+            encoding=None, explicit_start=None, explicit_end=None,
+            version=None, tags=None):
+        Emitter.__init__(self, stream, canonical=canonical,
+                indent=indent, width=width,
+                allow_unicode=allow_unicode, line_break=line_break)
+        Serializer.__init__(self, encoding=encoding,
+                explicit_start=explicit_start, explicit_end=explicit_end,
+                version=version, tags=tags)
+        Representer.__init__(self, default_style=default_style,
+                default_flow_style=default_flow_style)
+        Resolver.__init__(self)
+

lib/spack/external/yaml/error.py

@@ -0,0 +1,75 @@
+
+__all__ = ['Mark', 'YAMLError', 'MarkedYAMLError']
+
+class Mark(object):
+
+    def __init__(self, name, index, line, column, buffer, pointer):
+        self.name = name
+        self.index = index
+        self.line = line
+        self.column = column
+        self.buffer = buffer
+        self.pointer = pointer
+
+    def get_snippet(self, indent=4, max_length=75):
+        if self.buffer is None:
+            return None
+        head = ''
+        start = self.pointer
+        while start > 0 and self.buffer[start-1] not in u'\0\r\n\x85\u2028\u2029':
+            start -= 1
+            if self.pointer-start > max_length/2-1:
+                head = ' ... '
+                start += 5
+                break
+        tail = ''
+        end = self.pointer
+        while end < len(self.buffer) and self.buffer[end] not in u'\0\r\n\x85\u2028\u2029':
+            end += 1
+            if end-self.pointer > max_length/2-1:
+                tail = ' ... '
+                end -= 5
+                break
+        snippet = self.buffer[start:end].encode('utf-8')
+        return ' '*indent + head + snippet + tail + '\n'  \
+                + ' '*(indent+self.pointer-start+len(head)) + '^'
+
+    def __str__(self):
+        snippet = self.get_snippet()
+        where = "  in \"%s\", line %d, column %d"   \
+                % (self.name, self.line+1, self.column+1)
+        if snippet is not None:
+            where += ":\n"+snippet
+        return where
+
+class YAMLError(Exception):
+    pass
+
+class MarkedYAMLError(YAMLError):
+
+    def __init__(self, context=None, context_mark=None,
+            problem=None, problem_mark=None, note=None):
+        self.context = context
+        self.context_mark = context_mark
+        self.problem = problem
+        self.problem_mark = problem_mark
+        self.note = note
+
+    def __str__(self):
+        lines = []
+        if self.context is not None:
+            lines.append(self.context)
+        if self.context_mark is not None  \
+            and (self.problem is None or self.problem_mark is None
+                    or self.context_mark.name != self.problem_mark.name
+                    or self.context_mark.line != self.problem_mark.line
+                    or self.context_mark.column != self.problem_mark.column):
+            lines.append(str(self.context_mark))
+        if self.problem is not None:
+            lines.append(self.problem)
+        if self.problem_mark is not None:
+            lines.append(str(self.problem_mark))
+        if self.note is not None:
+            lines.append(self.note)
+        return '\n'.join(lines)
+

lib/spack/external/yaml/events.py

@@ -0,0 +1,86 @@
+
+# Abstract classes.
+
+class Event(object):
+    def __init__(self, start_mark=None, end_mark=None):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+    def __repr__(self):
+        attributes = [key for key in ['anchor', 'tag', 'implicit', 'value']
+                if hasattr(self, key)]
+        arguments = ', '.join(['%s=%r' % (key, getattr(self, key))
+                for key in attributes])
+        return '%s(%s)' % (self.__class__.__name__, arguments)
+
+class NodeEvent(Event):
+    def __init__(self, anchor, start_mark=None, end_mark=None):
+        self.anchor = anchor
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+
+class CollectionStartEvent(NodeEvent):
+    def __init__(self, anchor, tag, implicit, start_mark=None, end_mark=None,
+            flow_style=None):
+        self.anchor = anchor
+        self.tag = tag
+        self.implicit = implicit
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.flow_style = flow_style
+
+class CollectionEndEvent(Event):
+    pass
+
+# Implementations.
+
+class StreamStartEvent(Event):
+    def __init__(self, start_mark=None, end_mark=None, encoding=None):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.encoding = encoding
+
+class StreamEndEvent(Event):
+    pass
+
+class DocumentStartEvent(Event):
+    def __init__(self, start_mark=None, end_mark=None,
+            explicit=None, version=None, tags=None):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.explicit = explicit
+        self.version = version
+        self.tags = tags
+
+class DocumentEndEvent(Event):
+    def __init__(self, start_mark=None, end_mark=None,
+            explicit=None):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.explicit = explicit
+
+class AliasEvent(NodeEvent):
+    pass
+
+class ScalarEvent(NodeEvent):
+    def __init__(self, anchor, tag, implicit, value,
+            start_mark=None, end_mark=None, style=None):
+        self.anchor = anchor
+        self.tag = tag
+        self.implicit = implicit
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.style = style
+
+class SequenceStartEvent(CollectionStartEvent):
+    pass
+
+class SequenceEndEvent(CollectionEndEvent):
+    pass
+
+class MappingStartEvent(CollectionStartEvent):
+    pass
+
+class MappingEndEvent(CollectionEndEvent):
+    pass
+

lib/spack/external/yaml/loader.py

@@ -0,0 +1,40 @@
+
+__all__ = ['BaseLoader', 'SafeLoader', 'Loader']
+
+from reader import *
+from scanner import *
+from parser import *
+from composer import *
+from constructor import *
+from resolver import *
+
+class BaseLoader(Reader, Scanner, Parser, Composer, BaseConstructor, BaseResolver):
+
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        BaseConstructor.__init__(self)
+        BaseResolver.__init__(self)
+
+class SafeLoader(Reader, Scanner, Parser, Composer, SafeConstructor, Resolver):
+
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        SafeConstructor.__init__(self)
+        Resolver.__init__(self)
+
+class Loader(Reader, Scanner, Parser, Composer, Constructor, Resolver):
+
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        Constructor.__init__(self)
+        Resolver.__init__(self)
+

lib/spack/external/yaml/nodes.py

@@ -0,0 +1,49 @@
+
+class Node(object):
+    def __init__(self, tag, value, start_mark, end_mark):
+        self.tag = tag
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+    def __repr__(self):
+        value = self.value
+        #if isinstance(value, list):
+        #    if len(value) == 0:
+        #        value = '<empty>'
+        #    elif len(value) == 1:
+        #        value = '<1 item>'
+        #    else:
+        #        value = '<%d items>' % len(value)
+        #else:
+        #    if len(value) > 75:
+        #        value = repr(value[:70]+u' ... ')
+        #    else:
+        #        value = repr(value)
+        value = repr(value)
+        return '%s(tag=%r, value=%s)' % (self.__class__.__name__, self.tag, value)
+
+class ScalarNode(Node):
+    id = 'scalar'
+    def __init__(self, tag, value,
+            start_mark=None, end_mark=None, style=None):
+        self.tag = tag
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.style = style
+
+class CollectionNode(Node):
+    def __init__(self, tag, value,
+            start_mark=None, end_mark=None, flow_style=None):
+        self.tag = tag
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.flow_style = flow_style
+
+class SequenceNode(CollectionNode):
+    id = 'sequence'
+
+class MappingNode(CollectionNode):
+    id = 'mapping'
+

lib/spack/external/yaml/parser.py

@@ -0,0 +1,589 @@
+
+# The following YAML grammar is LL(1) and is parsed by a recursive descent
+# parser.
+#
+# stream            ::= STREAM-START implicit_document? explicit_document* STREAM-END
+# implicit_document ::= block_node DOCUMENT-END*
+# explicit_document ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
+# block_node_or_indentless_sequence ::=
+#                       ALIAS
+#                       | properties (block_content | indentless_block_sequence)?
+#                       | block_content
+#                       | indentless_block_sequence
+# block_node        ::= ALIAS
+#                       | properties block_content?
+#                       | block_content
+# flow_node         ::= ALIAS
+#                       | properties flow_content?
+#                       | flow_content
+# properties        ::= TAG ANCHOR? | ANCHOR TAG?
+# block_content     ::= block_collection | flow_collection | SCALAR
+# flow_content      ::= flow_collection | SCALAR
+# block_collection  ::= block_sequence | block_mapping
+# flow_collection   ::= flow_sequence | flow_mapping
+# block_sequence    ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
+# indentless_sequence   ::= (BLOCK-ENTRY block_node?)+
+# block_mapping     ::= BLOCK-MAPPING_START
+#                       ((KEY block_node_or_indentless_sequence?)?
+#                       (VALUE block_node_or_indentless_sequence?)?)*
+#                       BLOCK-END
+# flow_sequence     ::= FLOW-SEQUENCE-START
+#                       (flow_sequence_entry FLOW-ENTRY)*
+#                       flow_sequence_entry?
+#                       FLOW-SEQUENCE-END
+# flow_sequence_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
+# flow_mapping      ::= FLOW-MAPPING-START
+#                       (flow_mapping_entry FLOW-ENTRY)*
+#                       flow_mapping_entry?
+#                       FLOW-MAPPING-END
+# flow_mapping_entry    ::= flow_node | KEY flow_node? (VALUE flow_node?)?
+#
+# FIRST sets:
+#
+# stream: { STREAM-START }
+# explicit_document: { DIRECTIVE DOCUMENT-START }
+# implicit_document: FIRST(block_node)
+# block_node: { ALIAS TAG ANCHOR SCALAR BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START }
+# flow_node: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START }
+# block_content: { BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START SCALAR }
+# flow_content: { FLOW-SEQUENCE-START FLOW-MAPPING-START SCALAR }
+# block_collection: { BLOCK-SEQUENCE-START BLOCK-MAPPING-START }
+# flow_collection: { FLOW-SEQUENCE-START FLOW-MAPPING-START }
+# block_sequence: { BLOCK-SEQUENCE-START }
+# block_mapping: { BLOCK-MAPPING-START }
+# block_node_or_indentless_sequence: { ALIAS ANCHOR TAG SCALAR BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START BLOCK-ENTRY }
+# indentless_sequence: { ENTRY }
+# flow_collection: { FLOW-SEQUENCE-START FLOW-MAPPING-START }
+# flow_sequence: { FLOW-SEQUENCE-START }
+# flow_mapping: { FLOW-MAPPING-START }
+# flow_sequence_entry: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START KEY }
+# flow_mapping_entry: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START KEY }
+
+__all__ = ['Parser', 'ParserError']
+
+from error import MarkedYAMLError
+from tokens import *
+from events import *
+from scanner import *
+
+class ParserError(MarkedYAMLError):
+    pass
+
+class Parser(object):
+    # Since writing a recursive-descendant parser is a straightforward task, we
+    # do not give many comments here.
+
+    DEFAULT_TAGS = {
+        u'!':   u'!',
+        u'!!':  u'tag:yaml.org,2002:',
+    }
+
+    def __init__(self):
+        self.current_event = None
+        self.yaml_version = None
+        self.tag_handles = {}
+        self.states = []
+        self.marks = []
+        self.state = self.parse_stream_start
+
+    def dispose(self):
+        # Reset the state attributes (to clear self-references)
+        self.states = []
+        self.state = None
+
+    def check_event(self, *choices):
+        # Check the type of the next event.
+        if self.current_event is None:
+            if self.state:
+                self.current_event = self.state()
+        if self.current_event is not None:
+            if not choices:
+                return True
+            for choice in choices:
+                if isinstance(self.current_event, choice):
+                    return True
+        return False
+
+    def peek_event(self):
+        # Get the next event.
+        if self.current_event is None:
+            if self.state:
+                self.current_event = self.state()
+        return self.current_event
+
+    def get_event(self):
+        # Get the next event and proceed further.
+        if self.current_event is None:
+            if self.state:
+                self.current_event = self.state()
+        value = self.current_event
+        self.current_event = None
+        return value
+
+    # stream    ::= STREAM-START implicit_document? explicit_document* STREAM-END
+    # implicit_document ::= block_node DOCUMENT-END*
+    # explicit_document ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
+
+    def parse_stream_start(self):
+
+        # Parse the stream start.
+        token = self.get_token()
+        event = StreamStartEvent(token.start_mark, token.end_mark,
+                encoding=token.encoding)
+
+        # Prepare the next state.
+        self.state = self.parse_implicit_document_start
+
+        return event
+
+    def parse_implicit_document_start(self):
+
+        # Parse an implicit document.
+        if not self.check_token(DirectiveToken, DocumentStartToken,
+                StreamEndToken):
+            self.tag_handles = self.DEFAULT_TAGS
+            token = self.peek_token()
+            start_mark = end_mark = token.start_mark
+            event = DocumentStartEvent(start_mark, end_mark,
+                    explicit=False)
+
+            # Prepare the next state.
+            self.states.append(self.parse_document_end)
+            self.state = self.parse_block_node
+
+            return event
+
+        else:
+            return self.parse_document_start()
+
+    def parse_document_start(self):
+
+        # Parse any extra document end indicators.
+        while self.check_token(DocumentEndToken):
+            self.get_token()
+
+        # Parse an explicit document.
+        if not self.check_token(StreamEndToken):
+            token = self.peek_token()
+            start_mark = token.start_mark
+            version, tags = self.process_directives()
+            if not self.check_token(DocumentStartToken):
+                raise ParserError(None, None,
+                        "expected '<document start>', but found %r"
+                        % self.peek_token().id,
+                        self.peek_token().start_mark)
+            token = self.get_token()
+            end_mark = token.end_mark
+            event = DocumentStartEvent(start_mark, end_mark,
+                    explicit=True, version=version, tags=tags)
+            self.states.append(self.parse_document_end)
+            self.state = self.parse_document_content
+        else:
+            # Parse the end of the stream.
+            token = self.get_token()
+            event = StreamEndEvent(token.start_mark, token.end_mark)
+            assert not self.states
+            assert not self.marks
+            self.state = None
+        return event
+
+    def parse_document_end(self):
+
+        # Parse the document end.
+        token = self.peek_token()
+        start_mark = end_mark = token.start_mark
+        explicit = False
+        if self.check_token(DocumentEndToken):
+            token = self.get_token()
+            end_mark = token.end_mark
+            explicit = True
+        event = DocumentEndEvent(start_mark, end_mark,
+                explicit=explicit)
+
+        # Prepare the next state.
+        self.state = self.parse_document_start
+
+        return event
+
+    def parse_document_content(self):
+        if self.check_token(DirectiveToken,
+                DocumentStartToken, DocumentEndToken, StreamEndToken):
+            event = self.process_empty_scalar(self.peek_token().start_mark)
+            self.state = self.states.pop()
+            return event
+        else:
+            return self.parse_block_node()
+
+    def process_directives(self):
+        self.yaml_version = None
+        self.tag_handles = {}
+        while self.check_token(DirectiveToken):
+            token = self.get_token()
+            if token.name == u'YAML':
+                if self.yaml_version is not None:
+                    raise ParserError(None, None,
+                            "found duplicate YAML directive", token.start_mark)
+                major, minor = token.value
+                if major != 1:
+                    raise ParserError(None, None,
+                            "found incompatible YAML document (version 1.* is required)",
+                            token.start_mark)
+                self.yaml_version = token.value
+            elif token.name == u'TAG':
+                handle, prefix = token.value
+                if handle in self.tag_handles:
+                    raise ParserError(None, None,
+                            "duplicate tag handle %r" % handle.encode('utf-8'),
+                            token.start_mark)
+                self.tag_handles[handle] = prefix
+        if self.tag_handles:
+            value = self.yaml_version, self.tag_handles.copy()
+        else:
+            value = self.yaml_version, None
+        for key in self.DEFAULT_TAGS:
+            if key not in self.tag_handles:
+                self.tag_handles[key] = self.DEFAULT_TAGS[key]
+        return value
+
+    # block_node_or_indentless_sequence ::= ALIAS
+    #               | properties (block_content | indentless_block_sequence)?
+    #               | block_content
+    #               | indentless_block_sequence
+    # block_node    ::= ALIAS
+    #                   | properties block_content?
+    #                   | block_content
+    # flow_node     ::= ALIAS
+    #                   | properties flow_content?
+    #                   | flow_content
+    # properties    ::= TAG ANCHOR? | ANCHOR TAG?
+    # block_content     ::= block_collection | flow_collection | SCALAR
+    # flow_content      ::= flow_collection | SCALAR
+    # block_collection  ::= block_sequence | block_mapping
+    # flow_collection   ::= flow_sequence | flow_mapping
+
+    def parse_block_node(self):
+        return self.parse_node(block=True)
+
+    def parse_flow_node(self):
+        return self.parse_node()
+
+    def parse_block_node_or_indentless_sequence(self):
+        return self.parse_node(block=True, indentless_sequence=True)
+
+    def parse_node(self, block=False, indentless_sequence=False):
+        if self.check_token(AliasToken):
+            token = self.get_token()
+            event = AliasEvent(token.value, token.start_mark, token.end_mark)
+            self.state = self.states.pop()
+        else:
+            anchor = None
+            tag = None
+            start_mark = end_mark = tag_mark = None
+            if self.check_token(AnchorToken):
+                token = self.get_token()
+                start_mark = token.start_mark
+                end_mark = token.end_mark
+                anchor = token.value
+                if self.check_token(TagToken):
+                    token = self.get_token()
+                    tag_mark = token.start_mark
+                    end_mark = token.end_mark
+                    tag = token.value
+            elif self.check_token(TagToken):
+                token = self.get_token()
+                start_mark = tag_mark = token.start_mark
+                end_mark = token.end_mark
+                tag = token.value
+                if self.check_token(AnchorToken):
+                    token = self.get_token()
+                    end_mark = token.end_mark
+                    anchor = token.value
+            if tag is not None:
+                handle, suffix = tag
+                if handle is not None:
+                    if handle not in self.tag_handles:
+                        raise ParserError("while parsing a node", start_mark,
+                                "found undefined tag handle %r" % handle.encode('utf-8'),
+                                tag_mark)
+                    tag = self.tag_handles[handle]+suffix
+                else:
+                    tag = suffix
+            #if tag == u'!':
+            #    raise ParserError("while parsing a node", start_mark,
+            #            "found non-specific tag '!'", tag_mark,
+            #            "Please check 'http://pyyaml.org/wiki/YAMLNonSpecificTag' and share your opinion.")
+            if start_mark is None:
+                start_mark = end_mark = self.peek_token().start_mark
+            event = None
+            implicit = (tag is None or tag == u'!')
+            if indentless_sequence and self.check_token(BlockEntryToken):
+                end_mark = self.peek_token().end_mark
+                event = SequenceStartEvent(anchor, tag, implicit,
+                        start_mark, end_mark)
+                self.state = self.parse_indentless_sequence_entry
+            else:
+                if self.check_token(ScalarToken):
+                    token = self.get_token()
+                    end_mark = token.end_mark
+                    if (token.plain and tag is None) or tag == u'!':
+                        implicit = (True, False)
+                    elif tag is None:
+                        implicit = (False, True)
+                    else:
+                        implicit = (False, False)
+                    event = ScalarEvent(anchor, tag, implicit, token.value,
+                            start_mark, end_mark, style=token.style)
+                    self.state = self.states.pop()
+                elif self.check_token(FlowSequenceStartToken):
+                    end_mark = self.peek_token().end_mark
+                    event = SequenceStartEvent(anchor, tag, implicit,
+                            start_mark, end_mark, flow_style=True)
+                    self.state = self.parse_flow_sequence_first_entry
+                elif self.check_token(FlowMappingStartToken):
+                    end_mark = self.peek_token().end_mark
+                    event = MappingStartEvent(anchor, tag, implicit,
+                            start_mark, end_mark, flow_style=True)
+                    self.state = self.parse_flow_mapping_first_key
+                elif block and self.check_token(BlockSequenceStartToken):
+                    end_mark = self.peek_token().start_mark
+                    event = SequenceStartEvent(anchor, tag, implicit,
+                            start_mark, end_mark, flow_style=False)
+                    self.state = self.parse_block_sequence_first_entry
+                elif block and self.check_token(BlockMappingStartToken):
+                    end_mark = self.peek_token().start_mark
+                    event = MappingStartEvent(anchor, tag, implicit,
+                            start_mark, end_mark, flow_style=False)
+                    self.state = self.parse_block_mapping_first_key
+                elif anchor is not None or tag is not None:
+                    # Empty scalars are allowed even if a tag or an anchor is
+                    # specified.
+                    event = ScalarEvent(anchor, tag, (implicit, False), u'',
+                            start_mark, end_mark)
+                    self.state = self.states.pop()
+                else:
+                    if block:
+                        node = 'block'
+                    else:
+                        node = 'flow'
+                    token = self.peek_token()
+                    raise ParserError("while parsing a %s node" % node, start_mark,
+                            "expected the node content, but found %r" % token.id,
+                            token.start_mark)
+        return event
+
+    # block_sequence ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
+
+    def parse_block_sequence_first_entry(self):
+        token = self.get_token()
+        self.marks.append(token.start_mark)
+        return self.parse_block_sequence_entry()
+
+    def parse_block_sequence_entry(self):
+        if self.check_token(BlockEntryToken):
+            token = self.get_token()
+            if not self.check_token(BlockEntryToken, BlockEndToken):
+                self.states.append(self.parse_block_sequence_entry)
+                return self.parse_block_node()
+            else:
+                self.state = self.parse_block_sequence_entry
+                return self.process_empty_scalar(token.end_mark)
+        if not self.check_token(BlockEndToken):
+            token = self.peek_token()
+            raise ParserError("while parsing a block collection", self.marks[-1],
+                    "expected <block end>, but found %r" % token.id, token.start_mark)
+        token = self.get_token()
+        event = SequenceEndEvent(token.start_mark, token.end_mark)
+        self.state = self.states.pop()
+        self.marks.pop()
+        return event
+
+    # indentless_sequence ::= (BLOCK-ENTRY block_node?)+
+
+    def parse_indentless_sequence_entry(self):
+        if self.check_token(BlockEntryToken):
+            token = self.get_token()
+            if not self.check_token(BlockEntryToken,
+                    KeyToken, ValueToken, BlockEndToken):
+                self.states.append(self.parse_indentless_sequence_entry)
+                return self.parse_block_node()
+            else:
+                self.state = self.parse_indentless_sequence_entry
+                return self.process_empty_scalar(token.end_mark)
+        token = self.peek_token()
+        event = SequenceEndEvent(token.start_mark, token.start_mark)
+        self.state = self.states.pop()
+        return event
+
+    # block_mapping     ::= BLOCK-MAPPING_START
+    #                       ((KEY block_node_or_indentless_sequence?)?
+    #                       (VALUE block_node_or_indentless_sequence?)?)*
+    #                       BLOCK-END
+
+    def parse_block_mapping_first_key(self):
+        token = self.get_token()
+        self.marks.append(token.start_mark)
+        return self.parse_block_mapping_key()
+
+    def parse_block_mapping_key(self):
+        if self.check_token(KeyToken):
+            token = self.get_token()
+            if not self.check_token(KeyToken, ValueToken, BlockEndToken):
+                self.states.append(self.parse_block_mapping_value)
+                return self.parse_block_node_or_indentless_sequence()
+            else:
+                self.state = self.parse_block_mapping_value
+                return self.process_empty_scalar(token.end_mark)
+        if not self.check_token(BlockEndToken):
+            token = self.peek_token()
+            raise ParserError("while parsing a block mapping", self.marks[-1],
+                    "expected <block end>, but found %r" % token.id, token.start_mark)
+        token = self.get_token()
+        event = MappingEndEvent(token.start_mark, token.end_mark)
+        self.state = self.states.pop()
+        self.marks.pop()
+        return event
+
+    def parse_block_mapping_value(self):
+        if self.check_token(ValueToken):
+            token = self.get_token()
+            if not self.check_token(KeyToken, ValueToken, BlockEndToken):
+                self.states.append(self.parse_block_mapping_key)
+                return self.parse_block_node_or_indentless_sequence()
+            else:
+                self.state = self.parse_block_mapping_key
+                return self.process_empty_scalar(token.end_mark)
+        else:
+            self.state = self.parse_block_mapping_key
+            token = self.peek_token()
+            return self.process_empty_scalar(token.start_mark)
+
+    # flow_sequence     ::= FLOW-SEQUENCE-START
+    #                       (flow_sequence_entry FLOW-ENTRY)*
+    #                       flow_sequence_entry?
+    #                       FLOW-SEQUENCE-END
+    # flow_sequence_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
+    #
+    # Note that while production rules for both flow_sequence_entry and
+    # flow_mapping_entry are equal, their interpretations are different.
+    # For `flow_sequence_entry`, the part `KEY flow_node? (VALUE flow_node?)?`
+    # generate an inline mapping (set syntax).
+
+    def parse_flow_sequence_first_entry(self):
+        token = self.get_token()
+        self.marks.append(token.start_mark)
+        return self.parse_flow_sequence_entry(first=True)
+
+    def parse_flow_sequence_entry(self, first=False):
+        if not self.check_token(FlowSequenceEndToken):
+            if not first:
+                if self.check_token(FlowEntryToken):
+                    self.get_token()
+                else:
+                    token = self.peek_token()
+                    raise ParserError("while parsing a flow sequence", self.marks[-1],
+                            "expected ',' or ']', but got %r" % token.id, token.start_mark)
+            
+            if self.check_token(KeyToken):
+                token = self.peek_token()
+                event = MappingStartEvent(None, None, True,
+                        token.start_mark, token.end_mark,
+                        flow_style=True)
+                self.state = self.parse_flow_sequence_entry_mapping_key
+                return event
+            elif not self.check_token(FlowSequenceEndToken):
+                self.states.append(self.parse_flow_sequence_entry)
+                return self.parse_flow_node()
+        token = self.get_token()
+        event = SequenceEndEvent(token.start_mark, token.end_mark)
+        self.state = self.states.pop()
+        self.marks.pop()
+        return event
+
+    def parse_flow_sequence_entry_mapping_key(self):
+        token = self.get_token()
+        if not self.check_token(ValueToken,
+                FlowEntryToken, FlowSequenceEndToken):
+            self.states.append(self.parse_flow_sequence_entry_mapping_value)
+            return self.parse_flow_node()
+        else:
+            self.state = self.parse_flow_sequence_entry_mapping_value
+            return self.process_empty_scalar(token.end_mark)
+
+    def parse_flow_sequence_entry_mapping_value(self):
+        if self.check_token(ValueToken):
+            token = self.get_token()
+            if not self.check_token(FlowEntryToken, FlowSequenceEndToken):
+                self.states.append(self.parse_flow_sequence_entry_mapping_end)
+                return self.parse_flow_node()
+            else:
+                self.state = self.parse_flow_sequence_entry_mapping_end
+                return self.process_empty_scalar(token.end_mark)
+        else:
+            self.state = self.parse_flow_sequence_entry_mapping_end
+            token = self.peek_token()
+            return self.process_empty_scalar(token.start_mark)
+
+    def parse_flow_sequence_entry_mapping_end(self):
+        self.state = self.parse_flow_sequence_entry
+        token = self.peek_token()
+        return MappingEndEvent(token.start_mark, token.start_mark)
+
+    # flow_mapping  ::= FLOW-MAPPING-START
+    #                   (flow_mapping_entry FLOW-ENTRY)*
+    #                   flow_mapping_entry?
+    #                   FLOW-MAPPING-END
+    # flow_mapping_entry    ::= flow_node | KEY flow_node? (VALUE flow_node?)?
+
+    def parse_flow_mapping_first_key(self):
+        token = self.get_token()
+        self.marks.append(token.start_mark)
+        return self.parse_flow_mapping_key(first=True)
+
+    def parse_flow_mapping_key(self, first=False):
+        if not self.check_token(FlowMappingEndToken):
+            if not first:
+                if self.check_token(FlowEntryToken):
+                    self.get_token()
+                else:
+                    token = self.peek_token()
+                    raise ParserError("while parsing a flow mapping", self.marks[-1],
+                            "expected ',' or '}', but got %r" % token.id, token.start_mark)
+            if self.check_token(KeyToken):
+                token = self.get_token()
+                if not self.check_token(ValueToken,
+                        FlowEntryToken, FlowMappingEndToken):
+                    self.states.append(self.parse_flow_mapping_value)
+                    return self.parse_flow_node()
+                else:
+                    self.state = self.parse_flow_mapping_value
+                    return self.process_empty_scalar(token.end_mark)
+            elif not self.check_token(FlowMappingEndToken):
+                self.states.append(self.parse_flow_mapping_empty_value)
+                return self.parse_flow_node()
+        token = self.get_token()
+        event = MappingEndEvent(token.start_mark, token.end_mark)
+        self.state = self.states.pop()
+        self.marks.pop()
+        return event
+
+    def parse_flow_mapping_value(self):
+        if self.check_token(ValueToken):
+            token = self.get_token()
+            if not self.check_token(FlowEntryToken, FlowMappingEndToken):
+                self.states.append(self.parse_flow_mapping_key)
+                return self.parse_flow_node()
+            else:
+                self.state = self.parse_flow_mapping_key
+                return self.process_empty_scalar(token.end_mark)
+        else:
+            self.state = self.parse_flow_mapping_key
+            token = self.peek_token()
+            return self.process_empty_scalar(token.start_mark)
+
+    def parse_flow_mapping_empty_value(self):
+        self.state = self.parse_flow_mapping_key
+        return self.process_empty_scalar(self.peek_token().start_mark)
+
+    def process_empty_scalar(self, mark):
+        return ScalarEvent(None, None, (True, False), u'', mark, mark)
+

lib/spack/external/yaml/reader.py

@@ -0,0 +1,189 @@
+# This module contains abstractions for the input stream. You don't have to
+# looks further, there are no pretty code.
+#
+# We define two classes here.
+#
+#   Mark(source, line, column)
+# It's just a record and its only use is producing nice error messages.
+# Parser does not use it for any other purposes.
+#
+#   Reader(source, data)
+# Reader determines the encoding of `data` and converts it to unicode.
+# Reader provides the following methods and attributes:
+#   reader.peek(length=1) - return the next `length` characters
+#   reader.forward(length=1) - move the current position to `length` characters.
+#   reader.index - the number of the current character.
+#   reader.line, stream.column - the line and the column of the current character.
+
+__all__ = ['Reader', 'ReaderError']
+
+from error import YAMLError, Mark
+
+import codecs, re
+
+class ReaderError(YAMLError):
+
+    def __init__(self, name, position, character, encoding, reason):
+        self.name = name
+        self.character = character
+        self.position = position
+        self.encoding = encoding
+        self.reason = reason
+
+    def __str__(self):
+        if isinstance(self.character, str):
+            return "'%s' codec can't decode byte #x%02x: %s\n"  \
+                    "  in \"%s\", position %d"    \
+                    % (self.encoding, ord(self.character), self.reason,
+                            self.name, self.position)
+        else:
+            return "unacceptable character #x%04x: %s\n"    \
+                    "  in \"%s\", position %d"    \
+                    % (self.character, self.reason,
+                            self.name, self.position)
+
+class Reader(object):
+    # Reader:
+    # - determines the data encoding and converts it to unicode,
+    # - checks if characters are in allowed range,
+    # - adds '\0' to the end.
+
+    # Reader accepts
+    #  - a `str` object,
+    #  - a `unicode` object,
+    #  - a file-like object with its `read` method returning `str`,
+    #  - a file-like object with its `read` method returning `unicode`.
+
+    # Yeah, it's ugly and slow.
+
+    def __init__(self, stream, name=None):
+        self.stream = None
+        self.stream_pointer = 0
+        self.eof = True
+        self.buffer = u''
+        self.pointer = 0
+        self.raw_buffer = None
+        self.raw_decode = None
+        self.encoding = None
+        self.index = 0
+        self.line = 0
+        self.column = 0
+        if isinstance(stream, unicode):
+            self.name = "<unicode string>" if name is None else name
+            self.check_printable(stream)
+            self.buffer = stream+u'\0'
+        elif isinstance(stream, str):
+            self.name = "<string>" if name is None else name
+            self.raw_buffer = stream
+            self.determine_encoding()
+        else:
+            self.stream = stream
+            self.name = getattr(stream, 'name', "<file>") if name is None else name
+            self.eof = False
+            self.raw_buffer = ''
+            self.determine_encoding()
+
+    def peek(self, index=0):
+        try:
+            return self.buffer[self.pointer+index]
+        except IndexError:
+            self.update(index+1)
+            return self.buffer[self.pointer+index]
+
+    def prefix(self, length=1):
+        if self.pointer+length >= len(self.buffer):
+            self.update(length)
+        return self.buffer[self.pointer:self.pointer+length]
+
+    def forward(self, length=1):
+        if self.pointer+length+1 >= len(self.buffer):
+            self.update(length+1)
+        while length:
+            ch = self.buffer[self.pointer]
+            self.pointer += 1
+            self.index += 1
+            if ch in u'\n\x85\u2028\u2029'  \
+                    or (ch == u'\r' and self.buffer[self.pointer] != u'\n'):
+                self.line += 1
+                self.column = 0
+            elif ch != u'\uFEFF':
+                self.column += 1
+            length -= 1
+
+    def get_mark(self):
+        if self.stream is None:
+            return Mark(self.name, self.index, self.line, self.column,
+                    self.buffer, self.pointer)
+        else:
+            return Mark(self.name, self.index, self.line, self.column,
+                    None, None)
+
+    def determine_encoding(self):
+        while not self.eof and len(self.raw_buffer) < 2:
+            self.update_raw()
+        if not isinstance(self.raw_buffer, unicode):
+            if self.raw_buffer.startswith(codecs.BOM_UTF16_LE):
+                self.raw_decode = codecs.utf_16_le_decode
+                self.encoding = 'utf-16-le'
+            elif self.raw_buffer.startswith(codecs.BOM_UTF16_BE):
+                self.raw_decode = codecs.utf_16_be_decode
+                self.encoding = 'utf-16-be'
+            else:
+                self.raw_decode = codecs.utf_8_decode
+                self.encoding = 'utf-8'
+        self.update(1)
+
+    NON_PRINTABLE = re.compile(u'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD]')
+    def check_printable(self, data):
+        match = self.NON_PRINTABLE.search(data)
+        if match:
+            character = match.group()
+            position = self.index+(len(self.buffer)-self.pointer)+match.start()
+            raise ReaderError(self.name, position, ord(character),
+                    'unicode', "special characters are not allowed")
+
+    def update(self, length):
+        if self.raw_buffer is None:
+            return
+        self.buffer = self.buffer[self.pointer:]
+        self.pointer = 0
+        while len(self.buffer) < length:
+            if not self.eof:
+                self.update_raw()
+            if self.raw_decode is not None:
+                try:
+                    data, converted = self.raw_decode(self.raw_buffer,
+                            'strict', self.eof)
+                except UnicodeDecodeError, exc:
+                    character = exc.object[exc.start]
+                    if self.stream is not None:
+                        position = self.stream_pointer-len(self.raw_buffer)+exc.start
+                    else:
+                        position = exc.start
+                    raise ReaderError(self.name, position, character,
+                            exc.encoding, exc.reason)
+            else:
+                data = self.raw_buffer
+                converted = len(data)
+            self.check_printable(data)
+            self.buffer += data
+            self.raw_buffer = self.raw_buffer[converted:]
+            if self.eof:
+                self.buffer += u'\0'
+                self.raw_buffer = None
+                break
+
+    def update_raw(self, size=1024):
+        data = self.stream.read(size)
+        if data:
+            self.raw_buffer += data
+            self.stream_pointer += len(data)
+        else:
+            self.eof = True
+
+#try:
+#    import psyco
+#    psyco.bind(Reader)
+#except ImportError:
+#    pass
+

lib/spack/external/yaml/representer.py

@@ -0,0 +1,484 @@
+
+__all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
+    'RepresenterError']
+
+from error import *
+from nodes import *
+
+import datetime
+
+import sys, copy_reg, types
+
+class RepresenterError(YAMLError):
+    pass
+
+class BaseRepresenter(object):
+
+    yaml_representers = {}
+    yaml_multi_representers = {}
+
+    def __init__(self, default_style=None, default_flow_style=None):
+        self.default_style = default_style
+        self.default_flow_style = default_flow_style
+        self.represented_objects = {}
+        self.object_keeper = []
+        self.alias_key = None
+
+    def represent(self, data):
+        node = self.represent_data(data)
+        self.serialize(node)
+        self.represented_objects = {}
+        self.object_keeper = []
+        self.alias_key = None
+
+    def get_classobj_bases(self, cls):
+        bases = [cls]
+        for base in cls.__bases__:
+            bases.extend(self.get_classobj_bases(base))
+        return bases
+
+    def represent_data(self, data):
+        if self.ignore_aliases(data):
+            self.alias_key = None
+        else:
+            self.alias_key = id(data)
+        if self.alias_key is not None:
+            if self.alias_key in self.represented_objects:
+                node = self.represented_objects[self.alias_key]
+                #if node is None:
+                #    raise RepresenterError("recursive objects are not allowed: %r" % data)
+                return node
+            #self.represented_objects[alias_key] = None
+            self.object_keeper.append(data)
+        data_types = type(data).__mro__
+        if type(data) is types.InstanceType:
+            data_types = self.get_classobj_bases(data.__class__)+list(data_types)
+        if data_types[0] in self.yaml_representers:
+            node = self.yaml_representers[data_types[0]](self, data)
+        else:
+            for data_type in data_types:
+                if data_type in self.yaml_multi_representers:
+                    node = self.yaml_multi_representers[data_type](self, data)
+                    break
+            else:
+                if None in self.yaml_multi_representers:
+                    node = self.yaml_multi_representers[None](self, data)
+                elif None in self.yaml_representers:
+                    node = self.yaml_representers[None](self, data)
+                else:
+                    node = ScalarNode(None, unicode(data))
+        #if alias_key is not None:
+        #    self.represented_objects[alias_key] = node
+        return node
+
+    def add_representer(cls, data_type, representer):
+        if not 'yaml_representers' in cls.__dict__:
+            cls.yaml_representers = cls.yaml_representers.copy()
+        cls.yaml_representers[data_type] = representer
+    add_representer = classmethod(add_representer)
+
+    def add_multi_representer(cls, data_type, representer):
+        if not 'yaml_multi_representers' in cls.__dict__:
+            cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
+        cls.yaml_multi_representers[data_type] = representer
+    add_multi_representer = classmethod(add_multi_representer)
+
+    def represent_scalar(self, tag, value, style=None):
+        if style is None:
+            style = self.default_style
+        node = ScalarNode(tag, value, style=style)
+        if self.alias_key is not None:
+            self.represented_objects[self.alias_key] = node
+        return node
+
+    def represent_sequence(self, tag, sequence, flow_style=None):
+        value = []
+        node = SequenceNode(tag, value, flow_style=flow_style)
+        if self.alias_key is not None:
+            self.represented_objects[self.alias_key] = node
+        best_style = True
+        for item in sequence:
+            node_item = self.represent_data(item)
+            if not (isinstance(node_item, ScalarNode) and not node_item.style):
+                best_style = False
+            value.append(node_item)
+        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
+
+    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'):
+            mapping = mapping.items()
+            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
+
+    def ignore_aliases(self, data):
+        return False
+
+class SafeRepresenter(BaseRepresenter):
+
+    def ignore_aliases(self, data):
+        if data in [None, ()]:
+            return True
+        if isinstance(data, (str, unicode, bool, int, float)):
+            return True
+
+    def represent_none(self, data):
+        return self.represent_scalar(u'tag:yaml.org,2002:null',
+                u'null')
+
+    def represent_str(self, data):
+        tag = None
+        style = None
+        try:
+            data = unicode(data, 'ascii')
+            tag = u'tag:yaml.org,2002:str'
+        except UnicodeDecodeError:
+            try:
+                data = unicode(data, 'utf-8')
+                tag = u'tag:yaml.org,2002:str'
+            except UnicodeDecodeError:
+                data = data.encode('base64')
+                tag = u'tag:yaml.org,2002:binary'
+                style = '|'
+        return self.represent_scalar(tag, data, style=style)
+
+    def represent_unicode(self, data):
+        return self.represent_scalar(u'tag:yaml.org,2002:str', data)
+
+    def represent_bool(self, data):
+        if data:
+            value = u'true'
+        else:
+            value = u'false'
+        return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
+
+    def represent_int(self, data):
+        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
+
+    def represent_long(self, data):
+        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
+
+    inf_value = 1e300
+    while repr(inf_value) != repr(inf_value*inf_value):
+        inf_value *= inf_value
+
+    def represent_float(self, data):
+        if data != data or (data == 0.0 and data == 1.0):
+            value = u'.nan'
+        elif data == self.inf_value:
+            value = u'.inf'
+        elif data == -self.inf_value:
+            value = u'-.inf'
+        else:
+            value = unicode(repr(data)).lower()
+            # Note that in some cases `repr(data)` represents a float number
+            # without the decimal parts.  For instance:
+            #   >>> repr(1e17)
+            #   '1e17'
+            # Unfortunately, this is not a valid float representation according
+            # to the definition of the `!!float` tag.  We fix this by adding
+            # '.0' before the 'e' symbol.
+            if u'.' not in value and u'e' in value:
+                value = value.replace(u'e', u'.0e', 1)
+        return self.represent_scalar(u'tag:yaml.org,2002:float', value)
+
+    def represent_list(self, data):
+        #pairs = (len(data) > 0 and isinstance(data, list))
+        #if pairs:
+        #    for item in data:
+        #        if not isinstance(item, tuple) or len(item) != 2:
+        #            pairs = False
+        #            break
+        #if not pairs:
+            return self.represent_sequence(u'tag:yaml.org,2002:seq', data)
+        #value = []
+        #for item_key, item_value in data:
+        #    value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
+        #        [(item_key, item_value)]))
+        #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
+
+    def represent_dict(self, data):
+        return self.represent_mapping(u'tag:yaml.org,2002:map', data)
+
+    def represent_set(self, data):
+        value = {}
+        for key in data:
+            value[key] = None
+        return self.represent_mapping(u'tag:yaml.org,2002:set', value)
+
+    def represent_date(self, data):
+        value = unicode(data.isoformat())
+        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
+
+    def represent_datetime(self, data):
+        value = unicode(data.isoformat(' '))
+        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
+
+    def represent_yaml_object(self, tag, data, cls, flow_style=None):
+        if hasattr(data, '__getstate__'):
+            state = data.__getstate__()
+        else:
+            state = data.__dict__.copy()
+        return self.represent_mapping(tag, state, flow_style=flow_style)
+
+    def represent_undefined(self, data):
+        raise RepresenterError("cannot represent an object: %s" % data)
+
+SafeRepresenter.add_representer(type(None),
+        SafeRepresenter.represent_none)
+
+SafeRepresenter.add_representer(str,
+        SafeRepresenter.represent_str)
+
+SafeRepresenter.add_representer(unicode,
+        SafeRepresenter.represent_unicode)
+
+SafeRepresenter.add_representer(bool,
+        SafeRepresenter.represent_bool)
+
+SafeRepresenter.add_representer(int,
+        SafeRepresenter.represent_int)
+
+SafeRepresenter.add_representer(long,
+        SafeRepresenter.represent_long)
+
+SafeRepresenter.add_representer(float,
+        SafeRepresenter.represent_float)
+
+SafeRepresenter.add_representer(list,
+        SafeRepresenter.represent_list)
+
+SafeRepresenter.add_representer(tuple,
+        SafeRepresenter.represent_list)
+
+SafeRepresenter.add_representer(dict,
+        SafeRepresenter.represent_dict)
+
+SafeRepresenter.add_representer(set,
+        SafeRepresenter.represent_set)
+
+SafeRepresenter.add_representer(datetime.date,
+        SafeRepresenter.represent_date)
+
+SafeRepresenter.add_representer(datetime.datetime,
+        SafeRepresenter.represent_datetime)
+
+SafeRepresenter.add_representer(None,
+        SafeRepresenter.represent_undefined)
+
+class Representer(SafeRepresenter):
+
+    def represent_str(self, data):
+        tag = None
+        style = None
+        try:
+            data = unicode(data, 'ascii')
+            tag = u'tag:yaml.org,2002:str'
+        except UnicodeDecodeError:
+            try:
+                data = unicode(data, 'utf-8')
+                tag = u'tag:yaml.org,2002:python/str'
+            except UnicodeDecodeError:
+                data = data.encode('base64')
+                tag = u'tag:yaml.org,2002:binary'
+                style = '|'
+        return self.represent_scalar(tag, data, style=style)
+
+    def represent_unicode(self, data):
+        tag = None
+        try:
+            data.encode('ascii')
+            tag = u'tag:yaml.org,2002:python/unicode'
+        except UnicodeEncodeError:
+            tag = u'tag:yaml.org,2002:str'
+        return self.represent_scalar(tag, data)
+
+    def represent_long(self, data):
+        tag = u'tag:yaml.org,2002:int'
+        if int(data) is not data:
+            tag = u'tag:yaml.org,2002:python/long'
+        return self.represent_scalar(tag, unicode(data))
+
+    def represent_complex(self, data):
+        if data.imag == 0.0:
+            data = u'%r' % data.real
+        elif data.real == 0.0:
+            data = u'%rj' % data.imag
+        elif data.imag > 0:
+            data = u'%r+%rj' % (data.real, data.imag)
+        else:
+            data = u'%r%rj' % (data.real, data.imag)
+        return self.represent_scalar(u'tag:yaml.org,2002:python/complex', data)
+
+    def represent_tuple(self, data):
+        return self.represent_sequence(u'tag:yaml.org,2002:python/tuple', data)
+
+    def represent_name(self, data):
+        name = u'%s.%s' % (data.__module__, data.__name__)
+        return self.represent_scalar(u'tag:yaml.org,2002:python/name:'+name, u'')
+
+    def represent_module(self, data):
+        return self.represent_scalar(
+                u'tag:yaml.org,2002:python/module:'+data.__name__, u'')
+
+    def represent_instance(self, data):
+        # For instances of classic classes, we use __getinitargs__ and
+        # __getstate__ to serialize the data.
+
+        # If data.__getinitargs__ exists, the object must be reconstructed by
+        # calling cls(**args), where args is a tuple returned by
+        # __getinitargs__. Otherwise, the cls.__init__ method should never be
+        # called and the class instance is created by instantiating a trivial
+        # class and assigning to the instance's __class__ variable.
+
+        # If data.__getstate__ exists, it returns the state of the object.
+        # Otherwise, the state of the object is data.__dict__.
+
+        # We produce either a !!python/object or !!python/object/new node.
+        # If data.__getinitargs__ does not exist and state is a dictionary, we
+        # produce a !!python/object node . Otherwise we produce a
+        # !!python/object/new node.
+
+        cls = data.__class__
+        class_name = u'%s.%s' % (cls.__module__, cls.__name__)
+        args = None
+        state = None
+        if hasattr(data, '__getinitargs__'):
+            args = list(data.__getinitargs__())
+        if hasattr(data, '__getstate__'):
+            state = data.__getstate__()
+        else:
+            state = data.__dict__
+        if args is None and isinstance(state, dict):
+            return self.represent_mapping(
+                    u'tag:yaml.org,2002:python/object:'+class_name, state)
+        if isinstance(state, dict) and not state:
+            return self.represent_sequence(
+                    u'tag:yaml.org,2002:python/object/new:'+class_name, args)
+        value = {}
+        if args:
+            value['args'] = args
+        value['state'] = state
+        return self.represent_mapping(
+                u'tag:yaml.org,2002:python/object/new:'+class_name, value)
+
+    def represent_object(self, data):
+        # We use __reduce__ API to save the data. data.__reduce__ returns
+        # a tuple of length 2-5:
+        #   (function, args, state, listitems, dictitems)
+
+        # For reconstructing, we calls function(*args), then set its state,
+        # listitems, and dictitems if they are not None.
+
+        # A special case is when function.__name__ == '__newobj__'. In this
+        # case we create the object with args[0].__new__(*args).
+
+        # Another special case is when __reduce__ returns a string - we don't
+        # support it.
+
+        # We produce a !!python/object, !!python/object/new or
+        # !!python/object/apply node.
+
+        cls = type(data)
+        if cls in copy_reg.dispatch_table:
+            reduce = copy_reg.dispatch_table[cls](data)
+        elif hasattr(data, '__reduce_ex__'):
+            reduce = data.__reduce_ex__(2)
+        elif hasattr(data, '__reduce__'):
+            reduce = data.__reduce__()
+        else:
+            raise RepresenterError("cannot represent object: %r" % data)
+        reduce = (list(reduce)+[None]*5)[:5]
+        function, args, state, listitems, dictitems = reduce
+        args = list(args)
+        if state is None:
+            state = {}
+        if listitems is not None:
+            listitems = list(listitems)
+        if dictitems is not None:
+            dictitems = dict(dictitems)
+        if function.__name__ == '__newobj__':
+            function = args[0]
+            args = args[1:]
+            tag = u'tag:yaml.org,2002:python/object/new:'
+            newobj = True
+        else:
+            tag = u'tag:yaml.org,2002:python/object/apply:'
+            newobj = False
+        function_name = u'%s.%s' % (function.__module__, function.__name__)
+        if not args and not listitems and not dictitems \
+                and isinstance(state, dict) and newobj:
+            return self.represent_mapping(
+                    u'tag:yaml.org,2002:python/object:'+function_name, state)
+        if not listitems and not dictitems  \
+                and isinstance(state, dict) and not state:
+            return self.represent_sequence(tag+function_name, args)
+        value = {}
+        if args:
+            value['args'] = args
+        if state or not isinstance(state, dict):
+            value['state'] = state
+        if listitems:
+            value['listitems'] = listitems
+        if dictitems:
+            value['dictitems'] = dictitems
+        return self.represent_mapping(tag+function_name, value)
+
+Representer.add_representer(str,
+        Representer.represent_str)
+
+Representer.add_representer(unicode,
+        Representer.represent_unicode)
+
+Representer.add_representer(long,
+        Representer.represent_long)
+
+Representer.add_representer(complex,
+        Representer.represent_complex)
+
+Representer.add_representer(tuple,
+        Representer.represent_tuple)
+
+Representer.add_representer(type,
+        Representer.represent_name)
+
+Representer.add_representer(types.ClassType,
+        Representer.represent_name)
+
+Representer.add_representer(types.FunctionType,
+        Representer.represent_name)
+
+Representer.add_representer(types.BuiltinFunctionType,
+        Representer.represent_name)
+
+Representer.add_representer(types.ModuleType,
+        Representer.represent_module)
+
+Representer.add_multi_representer(types.InstanceType,
+        Representer.represent_instance)
+
+Representer.add_multi_representer(object,
+        Representer.represent_object)
+

lib/spack/external/yaml/resolver.py

@@ -0,0 +1,224 @@
+
+__all__ = ['BaseResolver', 'Resolver']
+
+from error import *
+from nodes import *
+
+import re
+
+class ResolverError(YAMLError):
+    pass
+
+class BaseResolver(object):
+
+    DEFAULT_SCALAR_TAG = u'tag:yaml.org,2002:str'
+    DEFAULT_SEQUENCE_TAG = u'tag:yaml.org,2002:seq'
+    DEFAULT_MAPPING_TAG = u'tag:yaml.org,2002:map'
+
+    yaml_implicit_resolvers = {}
+    yaml_path_resolvers = {}
+
+    def __init__(self):
+        self.resolver_exact_paths = []
+        self.resolver_prefix_paths = []
+
+    def add_implicit_resolver(cls, tag, regexp, first):
+        if not 'yaml_implicit_resolvers' in cls.__dict__:
+            cls.yaml_implicit_resolvers = cls.yaml_implicit_resolvers.copy()
+        if first is None:
+            first = [None]
+        for ch in first:
+            cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp))
+    add_implicit_resolver = classmethod(add_implicit_resolver)
+
+    def add_path_resolver(cls, tag, path, kind=None):
+        # Note: `add_path_resolver` is experimental.  The API could be changed.
+        # `new_path` is a pattern that is matched against the path from the
+        # root to the node that is being considered.  `node_path` elements are
+        # tuples `(node_check, index_check)`.  `node_check` is a node class:
+        # `ScalarNode`, `SequenceNode`, `MappingNode` or `None`.  `None`
+        # matches any kind of a node.  `index_check` could be `None`, a boolean
+        # value, a string value, or a number.  `None` and `False` match against
+        # any _value_ of sequence and mapping nodes.  `True` matches against
+        # any _key_ of a mapping node.  A string `index_check` matches against
+        # a mapping value that corresponds to a scalar key which content is
+        # equal to the `index_check` value.  An integer `index_check` matches
+        # against a sequence value with the index equal to `index_check`.
+        if not 'yaml_path_resolvers' in cls.__dict__:
+            cls.yaml_path_resolvers = cls.yaml_path_resolvers.copy()
+        new_path = []
+        for element in path:
+            if isinstance(element, (list, tuple)):
+                if len(element) == 2:
+                    node_check, index_check = element
+                elif len(element) == 1:
+                    node_check = element[0]
+                    index_check = True
+                else:
+                    raise ResolverError("Invalid path element: %s" % element)
+            else:
+                node_check = None
+                index_check = element
+            if node_check is str:
+                node_check = ScalarNode
+            elif node_check is list:
+                node_check = SequenceNode
+            elif node_check is dict:
+                node_check = MappingNode
+            elif node_check not in [ScalarNode, SequenceNode, MappingNode]  \
+                    and not isinstance(node_check, basestring)  \
+                    and node_check is not None:
+                raise ResolverError("Invalid node checker: %s" % node_check)
+            if not isinstance(index_check, (basestring, int))   \
+                    and index_check is not None:
+                raise ResolverError("Invalid index checker: %s" % index_check)
+            new_path.append((node_check, index_check))
+        if kind is str:
+            kind = ScalarNode
+        elif kind is list:
+            kind = SequenceNode
+        elif kind is dict:
+            kind = MappingNode
+        elif kind not in [ScalarNode, SequenceNode, MappingNode]    \
+                and kind is not None:
+            raise ResolverError("Invalid node kind: %s" % kind)
+        cls.yaml_path_resolvers[tuple(new_path), kind] = tag
+    add_path_resolver = classmethod(add_path_resolver)
+
+    def descend_resolver(self, current_node, current_index):
+        if not self.yaml_path_resolvers:
+            return
+        exact_paths = {}
+        prefix_paths = []
+        if current_node:
+            depth = len(self.resolver_prefix_paths)
+            for path, kind in self.resolver_prefix_paths[-1]:
+                if self.check_resolver_prefix(depth, path, kind,
+                        current_node, current_index):
+                    if len(path) > depth:
+                        prefix_paths.append((path, kind))
+                    else:
+                        exact_paths[kind] = self.yaml_path_resolvers[path, kind]
+        else:
+            for path, kind in self.yaml_path_resolvers:
+                if not path:
+                    exact_paths[kind] = self.yaml_path_resolvers[path, kind]
+                else:
+                    prefix_paths.append((path, kind))
+        self.resolver_exact_paths.append(exact_paths)
+        self.resolver_prefix_paths.append(prefix_paths)
+
+    def ascend_resolver(self):
+        if not self.yaml_path_resolvers:
+            return
+        self.resolver_exact_paths.pop()
+        self.resolver_prefix_paths.pop()
+
+    def check_resolver_prefix(self, depth, path, kind,
+            current_node, current_index):
+        node_check, index_check = path[depth-1]
+        if isinstance(node_check, basestring):
+            if current_node.tag != node_check:
+                return
+        elif node_check is not None:
+            if not isinstance(current_node, node_check):
+                return
+        if index_check is True and current_index is not None:
+            return
+        if (index_check is False or index_check is None)    \
+                and current_index is None:
+            return
+        if isinstance(index_check, basestring):
+            if not (isinstance(current_index, ScalarNode)
+                    and index_check == current_index.value):
+                return
+        elif isinstance(index_check, int) and not isinstance(index_check, bool):
+            if index_check != current_index:
+                return
+        return True
+
+    def resolve(self, kind, value, implicit):
+        if kind is ScalarNode and implicit[0]:
+            if value == u'':
+                resolvers = self.yaml_implicit_resolvers.get(u'', [])
+            else:
+                resolvers = self.yaml_implicit_resolvers.get(value[0], [])
+            resolvers += self.yaml_implicit_resolvers.get(None, [])
+            for tag, regexp in resolvers:
+                if regexp.match(value):
+                    return tag
+            implicit = implicit[1]
+        if self.yaml_path_resolvers:
+            exact_paths = self.resolver_exact_paths[-1]
+            if kind in exact_paths:
+                return exact_paths[kind]
+            if None in exact_paths:
+                return exact_paths[None]
+        if kind is ScalarNode:
+            return self.DEFAULT_SCALAR_TAG
+        elif kind is SequenceNode:
+            return self.DEFAULT_SEQUENCE_TAG
+        elif kind is MappingNode:
+            return self.DEFAULT_MAPPING_TAG
+
+class Resolver(BaseResolver):
+    pass
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:bool',
+        re.compile(ur'''^(?:yes|Yes|YES|no|No|NO
+                    |true|True|TRUE|false|False|FALSE
+                    |on|On|ON|off|Off|OFF)$''', re.X),
+        list(u'yYnNtTfFoO'))
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:float',
+        re.compile(ur'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
+                    |\.[0-9_]+(?:[eE][-+][0-9]+)?
+                    |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
+                    |[-+]?\.(?:inf|Inf|INF)
+                    |\.(?:nan|NaN|NAN))$''', re.X),
+        list(u'-+0123456789.'))
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:int',
+        re.compile(ur'''^(?:[-+]?0b[0-1_]+
+                    |[-+]?0[0-7_]+
+                    |[-+]?(?:0|[1-9][0-9_]*)
+                    |[-+]?0x[0-9a-fA-F_]+
+                    |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
+        list(u'-+0123456789'))
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:merge',
+        re.compile(ur'^(?:<<)$'),
+        [u'<'])
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:null',
+        re.compile(ur'''^(?: ~
+                    |null|Null|NULL
+                    | )$''', re.X),
+        [u'~', u'n', u'N', u''])
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:timestamp',
+        re.compile(ur'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
+                    |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
+                     (?:[Tt]|[ \t]+)[0-9][0-9]?
+                     :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
+                     (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
+        list(u'0123456789'))
+
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:value',
+        re.compile(ur'^(?:=)$'),
+        [u'='])
+
+# The following resolver is only for documentation purposes. It cannot work
+# because plain scalars cannot start with '!', '&', or '*'.
+Resolver.add_implicit_resolver(
+        u'tag:yaml.org,2002:yaml',
+        re.compile(ur'^(?:!|&|\*)$'),
+        list(u'!&*'))
+

lib/spack/external/yaml/serializer.py

@@ -0,0 +1,111 @@
+
+__all__ = ['Serializer', 'SerializerError']
+
+from error import YAMLError
+from events import *
+from nodes import *
+
+class SerializerError(YAMLError):
+    pass
+
+class Serializer(object):
+
+    ANCHOR_TEMPLATE = u'id%03d'
+
+    def __init__(self, encoding=None,
+            explicit_start=None, explicit_end=None, version=None, tags=None):
+        self.use_encoding = encoding
+        self.use_explicit_start = explicit_start
+        self.use_explicit_end = explicit_end
+        self.use_version = version
+        self.use_tags = tags
+        self.serialized_nodes = {}
+        self.anchors = {}
+        self.last_anchor_id = 0
+        self.closed = None
+
+    def open(self):
+        if self.closed is None:
+            self.emit(StreamStartEvent(encoding=self.use_encoding))
+            self.closed = False
+        elif self.closed:
+            raise SerializerError("serializer is closed")
+        else:
+            raise SerializerError("serializer is already opened")
+
+    def close(self):
+        if self.closed is None:
+            raise SerializerError("serializer is not opened")
+        elif not self.closed:
+            self.emit(StreamEndEvent())
+            self.closed = True
+
+    #def __del__(self):
+    #    self.close()
+
+    def serialize(self, node):
+        if self.closed is None:
+            raise SerializerError("serializer is not opened")
+        elif self.closed:
+            raise SerializerError("serializer is closed")
+        self.emit(DocumentStartEvent(explicit=self.use_explicit_start,
+            version=self.use_version, tags=self.use_tags))
+        self.anchor_node(node)
+        self.serialize_node(node, None, None)
+        self.emit(DocumentEndEvent(explicit=self.use_explicit_end))
+        self.serialized_nodes = {}
+        self.anchors = {}
+        self.last_anchor_id = 0
+
+    def anchor_node(self, node):
+        if node in self.anchors:
+            if self.anchors[node] is None:
+                self.anchors[node] = self.generate_anchor(node)
+        else:
+            self.anchors[node] = None
+            if isinstance(node, SequenceNode):
+                for item in node.value:
+                    self.anchor_node(item)
+            elif isinstance(node, MappingNode):
+                for key, value in node.value:
+                    self.anchor_node(key)
+                    self.anchor_node(value)
+
+    def generate_anchor(self, node):
+        self.last_anchor_id += 1
+        return self.ANCHOR_TEMPLATE % self.last_anchor_id
+
+    def serialize_node(self, node, parent, index):
+        alias = self.anchors[node]
+        if node in self.serialized_nodes:
+            self.emit(AliasEvent(alias))
+        else:
+            self.serialized_nodes[node] = True
+            self.descend_resolver(parent, index)
+            if isinstance(node, ScalarNode):
+                detected_tag = self.resolve(ScalarNode, node.value, (True, False))
+                default_tag = self.resolve(ScalarNode, node.value, (False, True))
+                implicit = (node.tag == detected_tag), (node.tag == default_tag)
+                self.emit(ScalarEvent(alias, node.tag, implicit, node.value,
+                    style=node.style))
+            elif isinstance(node, SequenceNode):
+                implicit = (node.tag
+                            == self.resolve(SequenceNode, node.value, True))
+                self.emit(SequenceStartEvent(alias, node.tag, implicit,
+                    flow_style=node.flow_style))
+                index = 0
+                for item in node.value:
+                    self.serialize_node(item, node, index)
+                    index += 1
+                self.emit(SequenceEndEvent())
+            elif isinstance(node, MappingNode):
+                implicit = (node.tag
+                            == self.resolve(MappingNode, node.value, True))
+                self.emit(MappingStartEvent(alias, node.tag, implicit,
+                    flow_style=node.flow_style))
+                for key, value in node.value:
+                    self.serialize_node(key, node, None)
+                    self.serialize_node(value, node, key)
+                self.emit(MappingEndEvent())
+            self.ascend_resolver()
+

lib/spack/external/yaml/tokens.py

@@ -0,0 +1,104 @@
+
+class Token(object):
+    def __init__(self, start_mark, end_mark):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+    def __repr__(self):
+        attributes = [key for key in self.__dict__
+                if not key.endswith('_mark')]
+        attributes.sort()
+        arguments = ', '.join(['%s=%r' % (key, getattr(self, key))
+                for key in attributes])
+        return '%s(%s)' % (self.__class__.__name__, arguments)
+
+#class BOMToken(Token):
+#    id = '<byte order mark>'
+
+class DirectiveToken(Token):
+    id = '<directive>'
+    def __init__(self, name, value, start_mark, end_mark):
+        self.name = name
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+
+class DocumentStartToken(Token):
+    id = '<document start>'
+
+class DocumentEndToken(Token):
+    id = '<document end>'
+
+class StreamStartToken(Token):
+    id = '<stream start>'
+    def __init__(self, start_mark=None, end_mark=None,
+            encoding=None):
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.encoding = encoding
+
+class StreamEndToken(Token):
+    id = '<stream end>'
+
+class BlockSequenceStartToken(Token):
+    id = '<block sequence start>'
+
+class BlockMappingStartToken(Token):
+    id = '<block mapping start>'
+
+class BlockEndToken(Token):
+    id = '<block end>'
+
+class FlowSequenceStartToken(Token):
+    id = '['
+
+class FlowMappingStartToken(Token):
+    id = '{'
+
+class FlowSequenceEndToken(Token):
+    id = ']'
+
+class FlowMappingEndToken(Token):
+    id = '}'
+
+class KeyToken(Token):
+    id = '?'
+
+class ValueToken(Token):
+    id = ':'
+
+class BlockEntryToken(Token):
+    id = '-'
+
+class FlowEntryToken(Token):
+    id = ','
+
+class AliasToken(Token):
+    id = '<alias>'
+    def __init__(self, value, start_mark, end_mark):
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+
+class AnchorToken(Token):
+    id = '<anchor>'
+    def __init__(self, value, start_mark, end_mark):
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+
+class TagToken(Token):
+    id = '<tag>'
+    def __init__(self, value, start_mark, end_mark):
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+
+class ScalarToken(Token):
+    id = '<scalar>'
+    def __init__(self, value, plain, start_mark, end_mark, style=None):
+        self.value = value
+        self.plain = plain
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.style = style
+

lib/spack/spack/__init__.py

@@ -42,7 +42,8 @@
 hooks_path     = join_path(module_path, "hooks")
 var_path       = join_path(prefix, "var", "spack")
 stage_path     = join_path(var_path, "stage")
-install_path   = join_path(prefix, "opt")
+opt_path       = join_path(prefix, "opt")
+install_path   = join_path(opt_path, "spack")
 share_path     = join_path(prefix, "share", "spack")
 
 #
@@ -65,8 +66,8 @@
 # This controls how spack lays out install prefixes and
 # stage directories.
 #
-from spack.directory_layout import SpecHashDirectoryLayout
-install_layout = SpecHashDirectoryLayout(install_path)
+from spack.directory_layout import YamlDirectoryLayout
+install_layout = YamlDirectoryLayout(install_path)
 
 #
 # This controls how things are concretized in spack.

lib/spack/spack/cmd/activate.py

@@ -38,17 +38,11 @@ def setup_parser(subparser):
 
 
 def activate(parser, args):
-    # TODO: shouldn't have to concretize here.  Fix DAG issues.
-    specs = spack.cmd.parse_specs(args.spec, concretize=True)
+    specs = spack.cmd.parse_specs(args.spec)
     if len(specs) != 1:
         tty.die("activate requires one spec.  %d given." % len(specs))
 
-    # TODO: remove this hack when DAG info is stored in dir layout.
-    # This ensures the ext spec is always normalized properly.
-    spack.db.get(specs[0])
-
     spec = spack.cmd.disambiguate_spec(specs[0])
-
     if not spec.package.is_extension:
         tty.die("%s is not an extension." % spec.name)
 

lib/spack/spack/cmd/deactivate.py

@@ -44,15 +44,10 @@ def setup_parser(subparser):
 
 
 def deactivate(parser, args):
-    # TODO: shouldn't have to concretize here.  Fix DAG issues.
-    specs = spack.cmd.parse_specs(args.spec, concretize=True)
+    specs = spack.cmd.parse_specs(args.spec)
     if len(specs) != 1:
         tty.die("deactivate requires one spec.  %d given." % len(specs))
 
-    # TODO: remove this hack when DAG info is stored properly.
-    # This ensures the ext spec is always normalized properly.
-    spack.db.get(specs[0])
-
     spec = spack.cmd.disambiguate_spec(specs[0])
     pkg = spec.package
 
@@ -67,9 +62,6 @@ def deactivate(parser, args):
                     ext_pkg.do_deactivate(force=True)
 
         elif pkg.is_extension:
-            # TODO: store DAG info properly (see above)
-            spec.normalize()
-
             if not args.force and not spec.package.activated:
                 tty.die("%s is not activated." % pkg.spec.short_spec)
 
@@ -81,10 +73,6 @@ def deactivate(parser, args):
             for name in topo_order:
                 espec = index[name]
                 epkg = espec.package
-
-                # TODO: store DAG info properly (see above)
-                epkg.spec.normalize()
-
                 if epkg.extends(pkg.extendee_spec):
                     if epkg.activated or args.force:
 

lib/spack/spack/cmd/find.py

@@ -40,9 +40,6 @@
 
 def setup_parser(subparser):
     format_group = subparser.add_mutually_exclusive_group()
-    format_group.add_argument(
-        '-l', '--long', action='store_const', dest='mode', const='long',
-        help='Show dependency hashes as well as versions.')
     format_group.add_argument(
         '-p', '--paths', action='store_const', dest='mode', const='paths',
         help='Show paths to package install directories')
@@ -50,13 +47,22 @@ def setup_parser(subparser):
         '-d', '--deps', action='store_const', dest='mode', const='deps',
         help='Show full dependency DAG of installed packages')
 
+    subparser.add_argument(
+        '-l', '--long', action='store_true', dest='long',
+        help='Show dependency hashes as well as versions.')
+
     subparser.add_argument(
         'query_specs', nargs=argparse.REMAINDER,
         help='optional specs to filter results')
 
 
+def gray_hash(spec):
+    return colorize('@K{[%s]}' % spec.dag_hash(7))
+
+
 def display_specs(specs, **kwargs):
     mode = kwargs.get('mode', 'short')
+    hashes = kwargs.get('long', False)
 
     # Make a dict with specs keyed by architecture and compiler.
     index = index_by(specs, ('architecture', 'compiler'))
@@ -85,13 +91,20 @@ def display_specs(specs, **kwargs):
 
         elif mode == 'deps':
             for spec in specs:
-                print spec.tree(indent=4, format='$_$@$+$#', color=True),
+                print spec.tree(
+                    format='$_$@$+',
+                    color=True,
+                    indent=4,
+                    prefix=(lambda s: gray_hash(s)) if hashes else None)
 
-        elif mode in ('short', 'long'):
-            fmt = '$-_$@$+'
-            if mode == 'long':
-                fmt += '$#'
-            colify(s.format(fmt, color=True) for s in specs)
+        elif mode == 'short':
+            def fmt(s):
+                string = ""
+                if hashes:
+                    string += gray_hash(s) + ' '
+                string += s.format('$-_$@$+', color=True)
+                return string
+            colify(fmt(s) for s in specs)
 
         else:
             raise ValueError(
@@ -125,5 +138,4 @@ def find(parser, args):
 
     if sys.stdout.isatty():
         tty.msg("%d installed packages." % len(specs))
-    display_specs(specs, mode=args.mode)
-
+    display_specs(specs, mode=args.mode, long=args.long)

lib/spack/spack/directory_layout.py

@@ -27,8 +27,9 @@
 import exceptions
 import hashlib
 import shutil
+import glob
 import tempfile
-from contextlib import closing
+from external import yaml
 
 import llnl.util.tty as tty
 from llnl.util.lang import memoized
@@ -81,7 +82,7 @@ def relative_path_for_spec(self, spec):
         raise NotImplementedError()
 
 
-    def make_path_for_spec(self, spec):
+    def create_install_directory(self, spec):
         """Creates the installation directory for a spec."""
         raise NotImplementedError()
 
@@ -131,7 +132,7 @@ def path_for_spec(self, spec):
         return os.path.join(self.root, path)
 
 
-    def remove_path_for_spec(self, spec):
+    def remove_install_directory(self, spec):
         """Removes a prefix and any empty parent directories from the root.
            Raised RemoveFailedError if something goes wrong.
         """
@@ -153,94 +154,70 @@ def remove_path_for_spec(self, spec):
             path = os.path.dirname(path)
 
 
-def traverse_dirs_at_depth(root, depth, path_tuple=(), curdepth=0):
-    """For each directory at <depth> within <root>, return a tuple representing
-       the ancestors of that directory.
-    """
-    if curdepth == depth and curdepth != 0:
-        yield path_tuple
-    elif depth > curdepth:
-        for filename in os.listdir(root):
-            child = os.path.join(root, filename)
-            if os.path.isdir(child):
-                child_tuple = path_tuple + (filename,)
-                for tup in traverse_dirs_at_depth(
-                        child, depth, child_tuple, curdepth+1):
-                    yield tup
-
-
-class SpecHashDirectoryLayout(DirectoryLayout):
+class YamlDirectoryLayout(DirectoryLayout):
     """Lays out installation directories like this::
-           <install_root>/
+           <install root>/
                <architecture>/
-                   <compiler>/
-                       name@version+variant-<dependency_hash>
+                   <compiler>-<compiler version>/
+                       <name>-<version>-<variants>-<hash>
 
-       Where dependency_hash is a SHA-1 hash prefix for the full package spec.
-       This accounts for dependencies.
+       The hash here is a SHA-1 hash for the full DAG plus the build
+       spec.  TODO: implement the build spec.
 
-       If there is ever a hash collision, you won't be able to install a new
-       package unless you use a larger prefix.  However, the full spec is stored
-       in a file called .spec in each directory, so you can migrate an entire
-       install directory to a new hash size pretty easily.
-
-       TODO: make a tool to migrate install directories to different hash sizes.
+       To avoid special characters (like ~) in the directory name,
+       only enabled variants are included in the install path.
+       Disabled variants are omitted.
     """
     def __init__(self, root, **kwargs):
-        """Prefix size is number of characters in the SHA-1 prefix to use
-           to make each hash unique.
-        """
-        spec_file_name = kwargs.get('spec_file_name', '.spec')
-        extension_file_name = kwargs.get('extension_file_name', '.extensions')
-        super(SpecHashDirectoryLayout, self).__init__(root)
-        self.spec_file_name = spec_file_name
-        self.extension_file_name = extension_file_name
+        super(YamlDirectoryLayout, self).__init__(root)
+        self.metadata_dir   = kwargs.get('metadata_dir', '.spack')
+        self.hash_len       = kwargs.get('hash_len', None)
+
+        self.spec_file_name      = 'spec.yaml'
+        self.extension_file_name = 'extensions.yaml'
 
         # Cache of already written/read extension maps.
         self._extension_maps = {}
 
+
     @property
     def hidden_file_paths(self):
-        return ('.spec', '.extensions')
+        return (self.metadata_dir,)
 
 
     def relative_path_for_spec(self, spec):
         _check_concrete(spec)
-        dir_name = spec.format('$_$@$+$#')
-        return join_path(spec.architecture, spec.compiler, dir_name)
+        enabled_variants = (
+            '-' + v.name for v in spec.variants.values()
+            if v.enabled)
+
+        dir_name = "%s-%s%s-%s" % (
+            spec.name,
+            spec.version,
+            ''.join(enabled_variants),
+            spec.dag_hash(self.hash_len))
+
+        path = join_path(
+            spec.architecture,
+            "%s-%s" % (spec.compiler.name, spec.compiler.version),
+            dir_name)
+
+        return path
 
 
     def write_spec(self, spec, path):
         """Write a spec out to a file."""
-        with closing(open(path, 'w')) as spec_file:
-            spec_file.write(spec.tree(ids=False, cover='nodes'))
+        _check_concrete(spec)
+        with open(path, 'w') as f:
+            spec.to_yaml(f)
 
 
     def read_spec(self, path):
         """Read the contents of a file and parse them as a spec"""
-        with closing(open(path)) as spec_file:
-            # Specs from files are assumed normal and concrete
-            spec = Spec(spec_file.read().replace('\n', ''))
+        with open(path) as f:
+            spec = Spec.from_yaml(f)
 
-        if all(spack.db.exists(s.name) for s in spec.traverse()):
-            copy = spec.copy()
-
-            # TODO: It takes a lot of time to normalize every spec on read.
-            # TODO: Storing graph info with spec files would fix this.
-            copy.normalize()
-            if copy.concrete:
-                return copy   # These are specs spack still understands.
-
-        # If we get here, either the spec is no longer in spack, or
-        # something about its dependencies has changed. So we need to
-        # just assume the read spec is correct.  We'll lose graph
-        # information if we do this, but this is just for best effort
-        # for commands like uninstall and find.  Currently Spack
-        # doesn't do anything that needs the graph info after install.
-
-        # TODO: store specs with full connectivity information, so
-        # that we don't have to normalize or reconstruct based on
-        # changing dependencies in the Spack tree.
+        # Specs read from actual installations are always concrete
         spec._normal = True
         spec._concrete = True
         return spec
@@ -249,10 +226,14 @@ def read_spec(self, path):
     def spec_file_path(self, spec):
         """Gets full path to spec file"""
         _check_concrete(spec)
-        return join_path(self.path_for_spec(spec), self.spec_file_name)
+        return join_path(self.metadata_path(spec), self.spec_file_name)
 
 
-    def make_path_for_spec(self, spec):
+    def metadata_path(self, spec):
+        return join_path(self.path_for_spec(spec), self.metadata_dir)
+
+
+    def create_install_directory(self, spec):
         _check_concrete(spec)
 
         path = self.path_for_spec(spec)
@@ -267,16 +248,13 @@ def make_path_for_spec(self, spec):
             if installed_spec == self.spec:
                 raise InstallDirectoryAlreadyExistsError(path)
 
-            spec_hash = self.hash_spec(spec)
-            installed_hash = self.hash_spec(installed_spec)
-            if installed_spec == spec_hash:
+            if spec.dag_hash() == installed_spec.dag_hash():
                 raise SpecHashCollisionError(installed_hash, spec_hash)
             else:
                 raise InconsistentInstallDirectoryError(
-                    'Spec file in %s does not match SHA-1 hash!'
-                    % spec_file_path)
+                    'Spec file in %s does not match hash!' % spec_file_path)
 
-        mkdirp(path)
+        mkdirp(self.metadata_path(spec))
         self.write_spec(spec, spec_file_path)
 
 
@@ -285,25 +263,50 @@ def all_specs(self):
         if not os.path.isdir(self.root):
             return []
 
-        specs = []
-        for path in traverse_dirs_at_depth(self.root, 3):
-            arch, compiler, last_dir = path
-            spec_file_path = join_path(
-                self.root, arch, compiler, last_dir, self.spec_file_name)
-            if os.path.exists(spec_file_path):
-                spec = self.read_spec(spec_file_path)
-                specs.append(spec)
-        return specs
+        pattern = join_path(
+            self.root, '*', '*', '*', self.metadata_dir, self.spec_file_name)
+        spec_files = glob.glob(pattern)
+        return [self.read_spec(s) for s in spec_files]
+
+
+    @memoized
+    def specs_by_hash(self):
+        by_hash = {}
+        for spec in self.all_specs():
+            by_hash[spec.dag_hash()] = spec
+        return by_hash
 
 
     def extension_file_path(self, spec):
         """Gets full path to an installed package's extension file"""
         _check_concrete(spec)
-        return join_path(self.path_for_spec(spec), self.extension_file_name)
+        return join_path(self.metadata_path(spec), self.extension_file_name)
+
+
+    def _write_extensions(self, spec, extensions):
+        path = self.extension_file_path(spec)
+
+        # Create a temp file in the same directory as the actual file.
+        dirname, basename = os.path.split(path)
+        tmp = tempfile.NamedTemporaryFile(
+            prefix=basename, dir=dirname, delete=False)
+
+        # write tmp file
+        with tmp:
+            yaml.dump({
+                'extensions' : [
+                    { ext.name : {
+                        'hash' : ext.dag_hash(),
+                        'path' : str(ext.prefix)
+                    }} for ext in sorted(extensions.values())]
+            }, tmp, default_flow_style=False)
+
+        # Atomic update by moving tmpfile on top of old one.
+        os.rename(tmp.name, path)
 
 
     def _extension_map(self, spec):
-        """Get a dict<name -> spec> for all extensions currnetly
+        """Get a dict<name -> spec> for all extensions currently
            installed for this package."""
         _check_concrete(spec)
 
@@ -313,16 +316,26 @@ def _extension_map(self, spec):
                 self._extension_maps[spec] = {}
 
             else:
+                by_hash = self.specs_by_hash()
                 exts = {}
-                with closing(open(path)) as ext_file:
-                    for line in ext_file:
-                        try:
-                            spec = Spec(line.strip())
-                            exts[spec.name] = spec
-                        except spack.error.SpackError, e:
-                            # TODO: do something better here -- should be
-                            # resilient to corrupt files.
-                            raise InvalidExtensionSpecError(str(e))
+                with open(path) as ext_file:
+                    yaml_file = yaml.load(ext_file)
+                    for entry in yaml_file['extensions']:
+                        name = next(iter(entry))
+                        dag_hash = entry[name]['hash']
+                        prefix   = entry[name]['path']
+
+                        if not dag_hash in by_hash:
+                            raise InvalidExtensionSpecError(
+                                "Spec %s not found in %s." % (dag_hash, prefix))
+
+                        ext_spec = by_hash[dag_hash]
+                        if not prefix == ext_spec.prefix:
+                            raise InvalidExtensionSpecError(
+                                "Prefix %s does not match spec with hash %s: %s"
+                                % (prefix, dag_hash, ext_spec))
+
+                        exts[ext_spec.name] = ext_spec
                 self._extension_maps[spec] = exts
 
         return self._extension_maps[spec]
@@ -330,6 +343,7 @@ def _extension_map(self, spec):
 
     def extension_map(self, spec):
         """Defensive copying version of _extension_map() for external API."""
+        _check_concrete(spec)
         return self._extension_map(spec).copy()
 
 
@@ -349,23 +363,6 @@ def check_activated(self, spec, ext_spec):
             raise NoSuchExtensionError(spec, ext_spec)
 
 
-    def _write_extensions(self, spec, extensions):
-        path = self.extension_file_path(spec)
-
-        # Create a temp file in the same directory as the actual file.
-        dirname, basename = os.path.split(path)
-        tmp = tempfile.NamedTemporaryFile(
-            prefix=basename, dir=dirname, delete=False)
-
-        # Write temp file.
-        with closing(tmp):
-            for extension in sorted(extensions.values()):
-                tmp.write("%s\n" % extension)
-
-        # Atomic update by moving tmpfile on top of old one.
-        os.rename(tmp.name, path)
-
-
     def add_extension(self, spec, ext_spec):
         _check_concrete(spec)
         _check_concrete(ext_spec)
@@ -399,9 +396,9 @@ def __init__(self, message):
 
 
 class SpecHashCollisionError(DirectoryLayoutError):
-    """Raised when there is a hash collision in an SpecHashDirectoryLayout."""
+    """Raised when there is a hash collision in an install layout."""
     def __init__(self, installed_spec, new_spec):
-        super(SpecHashDirectoryLayout, self).__init__(
+        super(SpecHashCollisionError, self).__init__(
             'Specs %s and %s have the same SHA-1 prefix!'
             % installed_spec, new_spec)
 
@@ -422,7 +419,7 @@ def __init__(self, message):
 
 
 class InstallDirectoryAlreadyExistsError(DirectoryLayoutError):
-    """Raised when make_path_for_sec is called unnecessarily."""
+    """Raised when create_install_directory is called unnecessarily."""
     def __init__(self, path):
         super(InstallDirectoryAlreadyExistsError, self).__init__(
             "Install path %s already exists!")
@@ -455,5 +452,3 @@ def __init__(self, spec, ext_spec):
         super(NoSuchExtensionError, self).__init__(
             "%s cannot be removed from %s because it's not activated."% (
                 ext_spec.short_spec, spec.short_spec))
-
-

lib/spack/spack/package.py

@@ -627,7 +627,7 @@ def url_version(self, version):
 
     def remove_prefix(self):
         """Removes the prefix for a package along with any empty parent directories."""
-        spack.install_layout.remove_path_for_spec(self.spec)
+        spack.install_layout.remove_install_directory(self.spec)
 
 
     def do_fetch(self):
@@ -783,7 +783,7 @@ def do_install(self, **kwargs):
         # create the install directory.  The install layout
         # handles this in case so that it can use whatever
         # package naming scheme it likes.
-        spack.install_layout.make_path_for_spec(self.spec)
+        spack.install_layout.create_install_directory(self.spec)
 
         def cleanup():
             if not keep_prefix:
@@ -804,11 +804,11 @@ def real_work():
                 spack.hooks.pre_install(self)
 
                 # Set up process's build environment before running install.
-                self.stage.chdir_to_source()
                 if fake_install:
                     self.do_fake_install()
                 else:
                     # Subclasses implement install() to do the real work.
+                    self.stage.chdir_to_source()
                     self.install(self.spec, self.prefix)
 
                 # Ensure that something was actually installed.
@@ -957,16 +957,13 @@ def do_activate(self, **kwargs):
         self._sanity_check_extension()
         force = kwargs.get('force', False)
 
-        # TODO: get rid of this normalize - DAG handling.
-        self.spec.normalize()
-
-        spack.install_layout.check_extension_conflict(self.extendee_spec, self.spec)
+        spack.install_layout.check_extension_conflict(
+            self.extendee_spec, self.spec)
 
+        # Activate any package dependencies that are also extensions.
         if not force:
             for spec in self.spec.traverse(root=False):
                 if spec.package.extends(self.extendee_spec):
-                    # TODO: fix this normalize() requirement -- revisit DAG handling.
-                    spec.package.spec.normalize()
                     if not spec.package.activated:
                         spec.package.do_activate(**kwargs)
 
@@ -994,6 +991,7 @@ def ignore(filename):
         conflict = tree.find_conflict(self.prefix, ignore=ignore)
         if conflict:
             raise ExtensionConflictError(conflict)
+
         tree.merge(self.prefix, ignore=ignore)
 
 

lib/spack/spack/spec.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.
@@ -93,8 +93,11 @@
 import sys
 import itertools
 import hashlib
+import base64
 from StringIO import StringIO
 from operator import attrgetter
+from external import yaml
+from external.yaml.error import MarkedYAMLError
 
 import llnl.util.tty as tty
 from llnl.util.lang import *
@@ -120,6 +123,7 @@
 enabled_variant_color  = '@B'
 disabled_variant_color = '@r'
 dependency_color       = '@.'
+hash_color             = '@K'
 
 """This map determines the coloring of specs when using color output.
    We make the fields different colors to enhance readability.
@@ -129,7 +133,8 @@
                  '=' : architecture_color,
                  '+' : enabled_variant_color,
                  '~' : disabled_variant_color,
-                 '^' : dependency_color }
+                 '^' : dependency_color,
+                 '#' : hash_color }
 
 """Regex used for splitting by spec field separators."""
 _separators = '[%s]' % ''.join(color_formats.keys())
@@ -258,6 +263,18 @@ def _cmp_key(self):
         return (self.name, self.versions)
 
 
+    def to_dict(self):
+        d = {'name' : self.name}
+        d.update(self.versions.to_dict())
+        return { 'compiler' : d }
+
+
+    @staticmethod
+    def from_dict(d):
+        d = d['compiler']
+        return CompilerSpec(d['name'], VersionList.from_dict(d))
+
+
     def __str__(self):
         out = self.name
         if self.versions and self.versions != _any_version:
@@ -604,18 +621,91 @@ def prefix(self):
         return Prefix(spack.install_layout.path_for_spec(self))
 
 
-    def dep_hash(self, length=None):
-        """Return a hash representing all dependencies of this spec
-           (direct and indirect).
+    def dag_hash(self, length=None):
+        """Return a hash of the entire spec DAG, including connectivity."""
+        yaml_text = yaml.dump(
+            self.to_node_dict(), default_flow_style=True, width=sys.maxint)
+        sha = hashlib.sha1(yaml_text)
+        return base64.b32encode(sha.digest()).lower()[:length]
+
+
+    def to_node_dict(self):
+        d = {
+            'variants' : dict(
+                (name,v.enabled) for name, v in self.variants.items()),
+            'arch' : self.architecture,
+            'dependencies' : dict((d, self.dependencies[d].dag_hash())
+                                  for d in sorted(self.dependencies))
+        }
+        if self.compiler:
+            d.update(self.compiler.to_dict())
+        else:
+            d['compiler'] = None
+        d.update(self.versions.to_dict())
+        return { self.name : d }
+
+
+    def to_yaml(self, stream=None):
+        node_list = []
+        for s in self.traverse(order='pre'):
+            node = s.to_node_dict()
+            node[s.name]['hash'] = s.dag_hash()
+            node_list.append(node)
+        return yaml.dump({ 'spec' : node_list },
+                         stream=stream, default_flow_style=False)
+
+
+    @staticmethod
+    def from_node_dict(node):
+        name = next(iter(node))
+        node = node[name]
+
+        spec = Spec(name)
+        spec.versions = VersionList.from_dict(node)
+        spec.architecture = node['arch']
+
+        if node['compiler'] is None:
+            spec.compiler = None
+        else:
+            spec.compiler = CompilerSpec.from_dict(node)
+
+        for name, enabled in node['variants'].items():
+            spec.variants[name] = VariantSpec(name, enabled)
+
+        return spec
+
+
+    @staticmethod
+    def from_yaml(stream):
+        """Construct a spec from YAML.
+
+        Parameters:
+        stream -- string or file object to read from.
+
+        TODO: currently discards hashes. Include hashes when they
+        represent more than the DAG does.
 
-           If you want this hash to be consistent, you should
-           concretize the spec first so that it is not ambiguous.
         """
-        sha = hashlib.sha1()
-        sha.update(self.dep_string())
-        full_hash = sha.hexdigest()
+        deps = {}
+        spec = None
 
-        return full_hash[:length]
+        try:
+            yfile = yaml.load(stream)
+        except MarkedYAMLError, e:
+            raise SpackYAMLError("error parsing YMAL spec:", str(e))
+
+        for node in yfile['spec']:
+            name = next(iter(node))
+            dep = Spec.from_node_dict(node)
+            if not spec:
+                spec = dep
+            deps[dep.name] = dep
+
+        for node in yfile['spec']:
+            name = next(iter(node))
+            for dep_name in node[name]['dependencies']:
+                deps[name].dependencies[dep_name] = deps[dep_name]
+        return spec
 
 
     def _concretize_helper(self, presets=None, visited=None):
@@ -1256,7 +1346,7 @@ def format(self, format_string='$_$@$%@$+$=', **kwargs):
                $%@  Compiler & compiler version
                $+   Options
                $=   Architecture
-               $#   Dependencies' 8-char sha1 prefix
+               $#   7-char prefix of DAG hash
                $$   $
 
            Optionally you can provide a width, e.g. $20_ for a 20-wide name.
@@ -1312,8 +1402,7 @@ def write(s, c):
                     if self.architecture:
                         write(fmt % (c + str(self.architecture)), c)
                 elif c == '#':
-                    if self.dependencies:
-                        out.write(fmt % ('-' + self.dep_hash(8)))
+                    out.write('-' + fmt % (self.dag_hash(7)))
                 elif c == '$':
                     if fmt != '':
                         raise ValueError("Can't use format width with $$.")
@@ -1359,12 +1448,15 @@ def tree(self, **kwargs):
         cover  = kwargs.pop('cover', 'nodes')
         indent = kwargs.pop('indent', 0)
         fmt    = kwargs.pop('format', '$_$@$%@$+$=')
+        prefix = kwargs.pop('prefix', None)
         check_kwargs(kwargs, self.tree)
 
         out = ""
         cur_id = 0
         ids = {}
         for d, node in self.traverse(order='pre', cover=cover, depth=True):
+            if prefix is not None:
+                out += prefix(node)
             out += " " * indent
             if depth:
                 out += "%-4d" % d
@@ -1740,3 +1832,7 @@ class UnsatisfiableDependencySpecError(UnsatisfiableSpecError):
     def __init__(self, provided, required):
         super(UnsatisfiableDependencySpecError, self).__init__(
             provided, required, "dependency")
+
+class SpackYAMLError(spack.error.SpackError):
+    def __init__(self, msg, yaml_error):
+        super(SpackError, self).__init__(msg, str(yaml_error))

lib/spack/spack/test/__init__.py

@@ -52,7 +52,8 @@
               'mirror',
               'url_extrapolate',
               'cc',
-              'link_tree']
+              'link_tree',
+              'spec_yaml']
 
 
 def list_tests():

lib/spack/spack/test/directory_layout.py

@@ -36,7 +36,11 @@
 import spack
 from spack.spec import Spec
 from spack.packages import PackageDB
-from spack.directory_layout import SpecHashDirectoryLayout
+from spack.directory_layout import YamlDirectoryLayout
+
+# number of packages to test (to reduce test time)
+max_packages = 10
+
 
 class DirectoryLayoutTest(unittest.TestCase):
     """Tests that a directory layout works correctly and produces a
@@ -44,11 +48,11 @@ class DirectoryLayoutTest(unittest.TestCase):
 
     def setUp(self):
         self.tmpdir = tempfile.mkdtemp()
-        self.layout = SpecHashDirectoryLayout(self.tmpdir)
+        self.layout = YamlDirectoryLayout(self.tmpdir)
 
 
     def tearDown(self):
-        shutil.rmtree(self.tmpdir, ignore_errors=True)
+        #shutil.rmtree(self.tmpdir, ignore_errors=True)
         self.layout = None
 
 
@@ -59,7 +63,9 @@ def test_read_and_write_spec(self):
            finally that the directory can be removed by the directory
            layout.
         """
-        for pkg in spack.db.all_packages():
+        packages = list(spack.db.all_packages())[:max_packages]
+
+        for pkg in packages:
             spec = pkg.spec
 
             # If a spec fails to concretize, just skip it.  If it is a
@@ -69,7 +75,7 @@ def test_read_and_write_spec(self):
             except:
                 continue
 
-            self.layout.make_path_for_spec(spec)
+            self.layout.create_install_directory(spec)
 
             install_dir = self.layout.path_for_spec(spec)
             spec_path = self.layout.spec_file_path(spec)
@@ -90,7 +96,7 @@ def test_read_and_write_spec(self):
 
             # Ensure that specs that come out "normal" are really normal.
             with closing(open(spec_path)) as spec_file:
-                read_separately = Spec(spec_file.read())
+                read_separately = Spec.from_yaml(spec_file.read())
 
                 read_separately.normalize()
                 self.assertEqual(read_separately, spec_from_file)
@@ -98,11 +104,11 @@ def test_read_and_write_spec(self):
                 read_separately.concretize()
                 self.assertEqual(read_separately, spec_from_file)
 
-            # Make sure the dep hash of the read-in spec is the same
-            self.assertEqual(spec.dep_hash(), spec_from_file.dep_hash())
+            # Make sure the hash of the read-in spec is the same
+            self.assertEqual(spec.dag_hash(), spec_from_file.dag_hash())
 
             # Ensure directories are properly removed
-            self.layout.remove_path_for_spec(spec)
+            self.layout.remove_install_directory(spec)
             self.assertFalse(os.path.isdir(install_dir))
             self.assertFalse(os.path.exists(install_dir))
 
@@ -120,12 +126,14 @@ def test_handle_unknown_package(self):
         """
         mock_db = PackageDB(spack.mock_packages_path)
 
-        not_in_mock = set(spack.db.all_package_names()).difference(
+        not_in_mock = set.difference(
+            set(spack.db.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 not_in_mock:
+        for pkg_name in packages:
             spec = spack.db.get(pkg_name).spec
 
             # If a spec fails to concretize, just skip it.  If it is a
@@ -135,7 +143,7 @@ def test_handle_unknown_package(self):
             except:
                 continue
 
-            self.layout.make_path_for_spec(spec)
+            self.layout.create_install_directory(spec)
             installed_specs[spec] = self.layout.path_for_spec(spec)
 
         tmp = spack.db
@@ -144,12 +152,29 @@ def test_handle_unknown_package(self):
         # Now check that even without the package files, we know
         # enough to read a spec from the spec file.
         for spec, path in installed_specs.items():
-            spec_from_file = self.layout.read_spec(join_path(path, '.spec'))
+            spec_from_file = self.layout.read_spec(
+                join_path(path, '.spack', 'spec.yaml'))
 
             # To satisfy these conditions, directory layouts need to
             # read in concrete specs from their install dirs somehow.
             self.assertEqual(path, self.layout.path_for_spec(spec_from_file))
             self.assertEqual(spec, spec_from_file)
-            self.assertEqual(spec.dep_hash(), spec_from_file.dep_hash())
+            self.assertTrue(spec.eq_dag(spec_from_file))
+            self.assertEqual(spec.dag_hash(), spec_from_file.dag_hash())
 
         spack.db = tmp
+
+
+    def test_find(self):
+        """Test that finding specs within an install layout works."""
+        packages = list(spack.db.all_packages())[:max_packages]
+        installed_specs = {}
+        for pkg in packages:
+            spec = pkg.spec.concretized()
+            installed_specs[spec.name] = spec
+            self.layout.create_install_directory(spec)
+
+        found_specs = dict((s.name, s) for s in self.layout.all_specs())
+        for name, spec in found_specs.items():
+            self.assertTrue(name in found_specs)
+            self.assertTrue(found_specs[name].eq_dag(spec))

lib/spack/spack/test/git_fetch.py

@@ -109,7 +109,7 @@ def test_fetch_master(self):
         })
 
 
-    def ztest_fetch_branch(self):
+    def test_fetch_branch(self):
         """Test fetching a branch."""
         self.try_fetch(self.repo.branch, self.repo.branch_file, {
             'git'    : self.repo.path,
@@ -117,7 +117,7 @@ def ztest_fetch_branch(self):
         })
 
 
-    def ztest_fetch_tag(self):
+    def test_fetch_tag(self):
         """Test fetching a tag."""
         self.try_fetch(self.repo.tag, self.repo.tag_file, {
             'git' : self.repo.path,
@@ -125,7 +125,7 @@ def ztest_fetch_tag(self):
         })
 
 
-    def ztest_fetch_commit(self):
+    def test_fetch_commit(self):
         """Test fetching a particular commit."""
         self.try_fetch(self.repo.r1, self.repo.r1_file, {
             'git'    : self.repo.path,

lib/spack/spack/test/install.py

@@ -33,7 +33,7 @@
 import spack
 from spack.stage import Stage
 from spack.fetch_strategy import URLFetchStrategy
-from spack.directory_layout import SpecHashDirectoryLayout
+from spack.directory_layout import YamlDirectoryLayout
 from spack.util.executable import which
 from spack.test.mock_packages_test import *
 from spack.test.mock_repo import MockArchive
@@ -55,7 +55,7 @@ def setUp(self):
         # installed pkgs and mock packages.
         self.tmpdir = tempfile.mkdtemp()
         self.orig_layout = spack.install_layout
-        spack.install_layout = SpecHashDirectoryLayout(self.tmpdir)
+        spack.install_layout = YamlDirectoryLayout(self.tmpdir)
 
 
     def tearDown(self):

lib/spack/spack/test/spec_yaml.py

@@ -0,0 +1,71 @@
+##############################################################################
+# 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://scalability-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
+##############################################################################
+"""Test YAML serialization for specs.
+
+YAML format preserves DAG informatoin in the spec.
+
+"""
+from spack.spec import Spec
+from spack.test.mock_packages_test import *
+
+class SpecDagTest(MockPackagesTest):
+
+    def check_yaml_round_trip(self, spec):
+        yaml_text = spec.to_yaml()
+        spec_from_yaml = Spec.from_yaml(yaml_text)
+        self.assertTrue(spec.eq_dag(spec_from_yaml))
+
+
+    def test_simple_spec(self):
+        spec = Spec('mpileaks')
+        self.check_yaml_round_trip(spec)
+
+
+    def test_normal_spec(self):
+        spec = Spec('mpileaks+debug~opt')
+        spec.normalize()
+        self.check_yaml_round_trip(spec)
+
+
+    def test_ambiguous_version_spec(self):
+        spec = Spec('mpileaks@1.0:5.0,6.1,7.3+debug~opt')
+        spec.normalize()
+        self.check_yaml_round_trip(spec)
+
+
+    def test_concrete_spec(self):
+        spec = Spec('mpileaks+debug~opt')
+        spec.concretize()
+        self.check_yaml_round_trip(spec)
+
+
+    def test_yaml_subdag(self):
+        spec = Spec('mpileaks^mpich+debug')
+        spec.concretize()
+
+        yaml_spec = Spec.from_yaml(spec.to_yaml())
+
+        for dep in ('callpath', 'mpich', 'dyninst', 'libdwarf', 'libelf'):
+            self.assertTrue(spec[dep].eq_dag(yaml_spec[dep]))

lib/spack/spack/version.py

@@ -587,6 +587,25 @@ def overlaps(self, other):
         return False
 
 
+    def to_dict(self):
+        """Generate human-readable dict for YAML."""
+        if self.concrete:
+            return { 'version'  : str(self[0]) }
+        else:
+            return { 'versions' : [str(v) for v in self] }
+
+
+    @staticmethod
+    def from_dict(dictionary):
+        """Parse dict from to_dict."""
+        if 'versions' in dictionary:
+            return VersionList(dictionary['versions'])
+        elif 'version' in dictionary:
+            return VersionList([dictionary['version']])
+        else:
+            raise ValueError("Dict must have 'version' or 'versions' in it.")
+
+
     @coerced
     def satisfies(self, other):
         """A VersionList satisfies another if some version in the list would

var/spack/mock_packages/mpileaks/package.py

@@ -33,6 +33,9 @@ class Mpileaks(Package):
     version(2.2, 'foobarbaz')
     version(2.3, 'foobarbaz')
 
+    variant('debug', default=False, description='Debug variant')
+    variant('opt',   default=False, description='Optimized variant')
+
     depends_on("mpi")
     depends_on("callpath")
 

var/spack/packages/python/package.py

@@ -139,7 +139,9 @@ def write_easy_install_pth(self, exts):
 
 
     def activate(self, ext_pkg, **args):
-        args.update(ignore=self.python_ignore(ext_pkg, args))
+        ignore=self.python_ignore(ext_pkg, args)
+        args.update(ignore=ignore)
+
         super(Python, self).activate(ext_pkg, **args)
 
         exts = spack.install_layout.extension_map(self.spec)