Lichen

Annotated inspector.py

86:009092555b74
2016-10-06 Paul Boddie Added an origin parent retrieval method, also fixing the ancestors method.
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#!/usr/bin/env python
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"""
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Inspect and obtain module structure.
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Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013,
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              2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk>
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program.  If not, see <http://www.gnu.org/licenses/>.
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"""
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from branching import BranchTracker
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from common import get_argnames, init_item, predefined_constants
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from modules import BasicModule, CacheWritingModule, InspectionNaming
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from errors import InspectError
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from referencing import Reference
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from resolving import NameResolving
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from results import AccessRef, InstanceRef, InvocationRef, LiteralSequenceRef, \
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                    LocalNameRef, NameRef, ResolvedNameRef
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import compiler
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import sys
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class InspectedModule(BasicModule, CacheWritingModule, NameResolving, InspectionNaming):
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    "A module inspector."
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    def __init__(self, name, importer):
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        "Initialise the module with basic details."
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        BasicModule.__init__(self, name, importer)
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        self.in_class = False
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        self.in_conditional = False
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        self.global_attr_accesses = {}
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        # Usage tracking.
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        self.trackers = []
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        self.attr_accessor_branches = {}
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    def __repr__(self):
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        return "InspectedModule(%r, %r)" % (self.name, self.importer)
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    # Principal methods.
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    def parse(self, filename):
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        "Parse the file having the given 'filename'."
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        self.parse_file(filename)
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        # Inspect the module.
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        self.start_tracking_in_module()
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        # Detect and record imports and globals declared in the module.
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        self.assign_general_local("__name__", self.get_constant("str", self.name))
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        self.assign_general_local("__file__", self.get_constant("str", filename))
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        self.process_structure(self.astnode)
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        # Set the class of the module after the definition has occurred.
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        ref = self.get_builtin("object")
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        self.set_name("__class__", ref)
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        # Get module-level attribute usage details.
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        self.stop_tracking_in_module()
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        # Collect external name references.
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        self.collect_names()
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    def complete(self):
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        "Complete the module inspection."
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        # Resolve names not definitively mapped to objects.
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        self.resolve()
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        # Define the invocation requirements in each namespace.
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        self.set_invocation_usage()
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        # Propagate to the importer information needed in subsequent activities.
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        self.propagate()
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    # Accessory methods.
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    def collect_names(self):
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        "Collect the names used by each scope."
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        for path in self.names_used.keys():
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            self.collect_names_for_path(path)
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    def collect_names_for_path(self, path):
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        """
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        Collect the names used by the given 'path'. These are propagated to the
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        importer in advance of any dependency resolution.
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        """
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        names = self.names_used.get(path)
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        if not names:
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            return
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        in_function = self.function_locals.has_key(path)
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        for name in names:
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            if name in predefined_constants or in_function and name in self.function_locals[path]:
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                continue
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            # Find local definitions (within dynamic namespaces).
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            key = "%s.%s" % (path, name)
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            ref = self.get_resolved_object(key)
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            if ref:
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                self.set_name_reference(key, ref)
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                continue
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            # Find global or known built-in definitions.
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            ref = self.get_resolved_global_or_builtin(name)
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            if ref:
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                self.set_name_reference(key, ref)
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                continue
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            # Find presumed built-in definitions.
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            ref = self.get_builtin(name)
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            self.set_name_reference(key, ref)
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    def set_name_reference(self, path, ref):
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        "Map the given name 'path' to 'ref'."
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        self.importer.all_name_references[path] = self.name_references[path] = ref
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    def get_resolved_global_or_builtin(self, name):
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        "Return the resolved global or built-in object with the given 'name'."
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        # In some circumstances, the name is neither global nor recognised by
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        # the importer. It is then assumed to be a general built-in.
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        return self.get_global(name) or \
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               self.importer.get_object("__builtins__.%s" % name)
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    # Module structure traversal.
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    def process_structure_node(self, n):
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        "Process the individual node 'n'."
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        # Module global detection.
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        if isinstance(n, compiler.ast.Global):
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            self.process_global_node(n)
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        # Module import declarations.
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        elif isinstance(n, compiler.ast.From):
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            self.process_from_node(n)
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        elif isinstance(n, compiler.ast.Import):
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            self.process_import_node(n)
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        # Nodes using operator module functions.
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        elif isinstance(n, compiler.ast.Operator):
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            return self.process_operator_node(n)
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        elif isinstance(n, compiler.ast.AugAssign):
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            self.process_augassign_node(n)
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        elif isinstance(n, compiler.ast.Compare):
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            return self.process_compare_node(n)
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        elif isinstance(n, compiler.ast.Slice):
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            return self.process_slice_node(n)
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        elif isinstance(n, compiler.ast.Sliceobj):
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            return self.process_sliceobj_node(n)
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        elif isinstance(n, compiler.ast.Subscript):
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            return self.process_subscript_node(n)
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        # Namespaces within modules.
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        elif isinstance(n, compiler.ast.Class):
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            self.process_class_node(n)
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        elif isinstance(n, compiler.ast.Function):
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            self.process_function_node(n, n.name)
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        elif isinstance(n, compiler.ast.Lambda):
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            return self.process_lambda_node(n)
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        # Assignments.
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        elif isinstance(n, compiler.ast.Assign):
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            # Handle each assignment node.
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            for node in n.nodes:
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                self.process_assignment_node(node, n.expr)
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        # Assignments within non-Assign nodes.
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        elif isinstance(n, compiler.ast.AssName):
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            self.process_assignment_node(n, None)
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        elif isinstance(n, compiler.ast.AssAttr):
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            self.process_attribute_access(n)
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        # Accesses.
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        elif isinstance(n, compiler.ast.Getattr):
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            return self.process_attribute_access(n)
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        # Name recording for later testing.
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        elif isinstance(n, compiler.ast.Name):
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            return self.process_name_node(n)
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        # Conditional statement tracking.
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        elif isinstance(n, compiler.ast.For):
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            self.process_for_node(n)
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        elif isinstance(n, compiler.ast.While):
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            self.process_while_node(n)
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        elif isinstance(n, compiler.ast.If):
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            self.process_if_node(n)
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        elif isinstance(n, (compiler.ast.And, compiler.ast.Or)):
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            return self.process_logical_node(n)
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        # Exception control-flow tracking.
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        elif isinstance(n, compiler.ast.TryExcept):
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            self.process_try_node(n)
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        elif isinstance(n, compiler.ast.TryFinally):
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            self.process_try_finally_node(n)
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        # Control-flow modification statements.
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        elif isinstance(n, compiler.ast.Break):
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            self.trackers[-1].suspend_broken_branch()
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        elif isinstance(n, compiler.ast.Continue):
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            self.trackers[-1].suspend_continuing_branch()
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        elif isinstance(n, compiler.ast.Raise):
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            self.process_structure(n)
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            self.trackers[-1].abandon_branch()
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        elif isinstance(n, compiler.ast.Return):
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            self.process_structure(n)
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            self.trackers[-1].abandon_returning_branch()
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        # Invocations.
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        elif isinstance(n, compiler.ast.CallFunc):
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            return self.process_invocation_node(n)
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        # Constant usage.
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        elif isinstance(n, compiler.ast.Const):
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            return self.get_literal_instance(n, n.value.__class__.__name__)
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        elif isinstance(n, compiler.ast.Dict):
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            return self.get_literal_instance(n, "dict")
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        elif isinstance(n, compiler.ast.List):
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            return self.get_literal_instance(n, "list")
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        elif isinstance(n, compiler.ast.Tuple):
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            return self.get_literal_instance(n, "tuple")
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        # Unsupported nodes.
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        elif isinstance(n, compiler.ast.GenExpr):
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            raise InspectError("Generator expressions are not supported.", self.get_namespace_path(), n)
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        elif isinstance(n, compiler.ast.IfExp):
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            raise InspectError("If-else expressions are not supported.", self.get_namespace_path(), n)
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        elif isinstance(n, compiler.ast.ListComp):
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            raise InspectError("List comprehensions are not supported.", self.get_namespace_path(), n)
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        # All other nodes are processed depth-first.
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        else:
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            self.process_structure(n)
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        # By default, no expression details are returned.
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        return None
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    # Specific node handling.
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    def process_assignment_node(self, n, expr):
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        "Process the individual node 'n' to be assigned the contents of 'expr'."
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        # Names and attributes are assigned the entire expression.
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        if isinstance(n, compiler.ast.AssName):
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            if n.name == "self":
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                raise InspectError("Redefinition of self is not allowed.", self.get_namespace_path(), n)
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            name_ref = expr and self.process_structure_node(expr)
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            # Name assignments populate either function namespaces or the
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            # general namespace hierarchy.
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            self.assign_general_local(n.name, name_ref)
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            # Record usage of the name.
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            self.record_name(n.name)
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        elif isinstance(n, compiler.ast.AssAttr):
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            if expr: self.process_structure_node(expr)
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            self.process_attribute_access(n)
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        # Lists and tuples are matched against the expression and their
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        # items assigned to expression items.
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        elif isinstance(n, (compiler.ast.AssList, compiler.ast.AssTuple)):
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            self.process_assignment_node_items(n, expr)
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        # Slices and subscripts are permitted within assignment nodes.
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        elif isinstance(n, compiler.ast.Slice):
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            self.process_slice_node(n, expr)
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        elif isinstance(n, compiler.ast.Subscript):
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            self.process_subscript_node(n, expr)
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    def process_attribute_access(self, n):
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        "Process the given attribute access node 'n'."
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        # Obtain any completed chain and return the reference to it.
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        name_ref = self.process_attribute_chain(n)
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        if self.have_access_expression(n):
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            return name_ref
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        # Where the start of the chain of attributes has been reached, determine
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        # the complete access.
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        # Given a non-access node, this chain can be handled in its entirety,
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        # either being name-based and thus an access rooted on a name, or being
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        # based on some other node and thus an anonymous access of some kind.
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        path = self.get_namespace_path()
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        # Start with the the full attribute chain.
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        remaining = self.attrs
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        attrnames = ".".join(remaining)
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        # If the accessor cannot be identified, or where attributes
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        # remain in an attribute chain, record the anonymous accesses.
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        if not isinstance(name_ref, NameRef): # includes ResolvedNameRef
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            assignment = isinstance(n, compiler.ast.AssAttr)
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            init_item(self.attr_accesses, path, set)
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            self.attr_accesses[path].add(attrnames)
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            self.record_access_details(None, attrnames, assignment)
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            del self.attrs[0]
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            return
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        # Name-based accesses will handle the first attribute in a
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        # chain.
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        else:
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            attrname = remaining[0]
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            # Attribute assignments are used to identify instance attributes.
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            if isinstance(n, compiler.ast.AssAttr) and \
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                self.in_class and self.in_function and n.expr.name == "self":
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                self.set_instance_attr(attrname)
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            # Record attribute usage using any name local to this namespace,
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            # if assigned in the namespace, or using an external name
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            # (presently just globals within classes).
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            name = self.get_name_for_tracking(name_ref.name, name_ref.final())
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            tracker = self.trackers[-1]
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            immediate_access = len(self.attrs) == 1
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            assignment = immediate_access and isinstance(n, compiler.ast.AssAttr)
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            del self.attrs[0]
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            # Record global-based chains for subsequent resolution.
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            is_global = self.in_function and not self.function_locals[path].has_key(name) or \
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                        not self.in_function
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            if is_global:
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                self.record_global_access_details(name, attrnames)
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            # Make sure the name is being tracked: global names will not
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            # already be initialised in a branch and must be added
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            # explicitly.
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            if not tracker.have_name(name):
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                tracker.assign_names([name])
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                if self.in_function:
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                    self.scope_globals[path].add(name)
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            # Record attribute usage in the tracker, and record the branch
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            # information for the access.
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            branches = tracker.use_attribute(name, attrname)
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            if not branches:
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                raise InspectError("Name %s is accessed using %s before an assignment." % (
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                    name, attrname), path, n)
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            self.record_branches_for_access(branches, name, attrnames)
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            access_number = self.record_access_details(name, attrnames, assignment)
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            return AccessRef(name, attrnames, access_number)
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    def process_class_node(self, n):
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        "Process the given class node 'n'."
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        path = self.get_namespace_path()
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        # To avoid notions of class "versions" where the same definition
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        # might be parameterised with different state and be referenced
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        # elsewhere (as base classes, for example), classes in functions or
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        # conditions are forbidden.
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        if self.in_function or self.in_conditional:
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            print >>sys.stderr, "In %s, class %s in function or conditional statement ignored." % (
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                path, n.name)
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            return
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        # Resolve base classes.
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        bases = []
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        for base in n.bases:
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            base_class = self.get_class(base)
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            if not base_class:
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                print >>sys.stderr, "In %s, class %s has unidentifiable base class: %s" % (
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                    path, n.name, base)
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                return
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            else:
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                bases.append(base_class)
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        # Record bases for the class and retain the class name.
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        class_name = self.get_object_path(n.name)
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        if not bases and class_name != "__builtins__.core.object":
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            ref = self.get_object("__builtins__.object")
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            bases.append(ref)
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        self.importer.classes[class_name] = self.classes[class_name] = bases
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        self.importer.subclasses[class_name] = set()
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        self.scope_globals[class_name] = set()
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        # Set the definition before entering the namespace rather than
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        # afterwards because methods may reference it. In normal Python,
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        # a class is not accessible until the definition is complete, but
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        # methods can generally reference it since upon being called the
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        # class will already exist.
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        self.set_definition(n.name, "<class>")
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        in_class = self.in_class
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        self.in_class = class_name
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        self.set_instance_attr("__class__", Reference("<class>", class_name))
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        self.enter_namespace(n.name)
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        self.set_name("__fn__") # special instantiator attribute
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        self.set_name("__args__") # special instantiator attribute
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        self.assign_general_local("__name__", self.get_constant("str", class_name))
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        self.process_structure_node(n.code)
paul@0 511
        self.exit_namespace()
paul@0 512
        self.in_class = in_class
paul@0 513
paul@0 514
    def process_from_node(self, n):
paul@0 515
paul@0 516
        "Process the given node 'n', importing from another module."
paul@0 517
paul@0 518
        path = self.get_namespace_path()
paul@0 519
paul@12 520
        module_name, names = self.get_module_name(n)
paul@12 521
        if module_name == self.name:
paul@12 522
            raise InspectError("Cannot import from the current module.", path, n)
paul@0 523
paul@18 524
        self.queue_module(module_name)
paul@0 525
paul@0 526
        # Attempt to obtain the referenced objects.
paul@0 527
paul@0 528
        for name, alias in n.names:
paul@0 529
            if name == "*":
paul@12 530
                raise InspectError("Only explicitly specified names can be imported from modules.", path, n)
paul@0 531
paul@0 532
            # Explicit names.
paul@0 533
paul@12 534
            ref = self.import_name_from_module(name, module_name)
paul@0 535
            value = ResolvedNameRef(alias or name, ref)
paul@0 536
            self.set_general_local(alias or name, value)
paul@0 537
paul@0 538
    def process_function_node(self, n, name):
paul@0 539
paul@0 540
        """
paul@0 541
        Process the given function or lambda node 'n' with the given 'name'.
paul@0 542
        """
paul@0 543
paul@0 544
        is_lambda = isinstance(n, compiler.ast.Lambda)
paul@0 545
paul@0 546
        # Where a function is declared conditionally, use a separate name for
paul@0 547
        # the definition, and assign the definition to the stated name.
paul@0 548
paul@0 549
        if (self.in_conditional or self.in_function) and not is_lambda:
paul@0 550
            original_name = name
paul@0 551
            name = self.get_lambda_name()
paul@0 552
        else:
paul@0 553
            original_name = None
paul@0 554
paul@0 555
        # Initialise argument and local records.
paul@0 556
paul@0 557
        function_name = self.get_object_path(name)
paul@46 558
        argnames = get_argnames(n.argnames)
paul@48 559
        is_method = self.in_class and not self.in_function
paul@0 560
paul@48 561
        # Remove explicit "self" from method parameters.
paul@46 562
paul@48 563
        if is_method and argnames and argnames[0] == "self":
paul@48 564
            del argnames[0]
paul@48 565
paul@48 566
        # Copy and propagate the parameters.
paul@46 567
paul@46 568
        self.importer.function_parameters[function_name] = \
paul@48 569
        self.function_parameters[function_name] = argnames[:]
paul@46 570
paul@46 571
        # Define all arguments/parameters in the local namespace.
paul@46 572
paul@0 573
        locals = self.function_locals[function_name] = {}
paul@0 574
paul@48 575
        # Insert "self" into method locals.
paul@48 576
paul@48 577
        if is_method:
paul@48 578
            argnames.insert(0, "self")
paul@48 579
paul@47 580
        # Define "self" in terms of the class if in a method.
paul@47 581
        # This does not diminish the need for type-narrowing in the deducer.
paul@47 582
paul@47 583
        if argnames:
paul@48 584
            if self.in_class and not self.in_function and argnames[0] == "self":
paul@47 585
                locals[argnames[0]] = Reference("<instance>", self.in_class)
paul@47 586
            else:
paul@47 587
                locals[argnames[0]] = Reference("<var>")
paul@47 588
paul@47 589
        for argname in argnames[1:]:
paul@0 590
            locals[argname] = Reference("<var>")
paul@0 591
paul@0 592
        globals = self.scope_globals[function_name] = set()
paul@0 593
paul@0 594
        # Process the defaults.
paul@0 595
paul@0 596
        defaults = self.importer.function_defaults[function_name] = \
paul@0 597
                   self.function_defaults[function_name] = []
paul@0 598
paul@0 599
        for argname, default in compiler.ast.get_defaults(n):
paul@0 600
            if default:
paul@0 601
paul@0 602
                # Obtain any reference for the default.
paul@0 603
paul@0 604
                name_ref = self.process_structure_node(default)
paul@0 605
                defaults.append((argname, name_ref.is_name() and name_ref.reference() or Reference("<var>")))
paul@0 606
paul@0 607
        # Reset conditional tracking to focus on the function contents.
paul@0 608
paul@0 609
        in_conditional = self.in_conditional
paul@0 610
        self.in_conditional = False
paul@0 611
paul@0 612
        in_function = self.in_function
paul@0 613
        self.in_function = function_name
paul@0 614
paul@0 615
        self.enter_namespace(name)
paul@0 616
paul@0 617
        # Track attribute usage within the namespace.
paul@0 618
paul@0 619
        path = self.get_namespace_path()
paul@0 620
paul@0 621
        self.start_tracking(locals)
paul@0 622
        self.process_structure_node(n.code)
paul@0 623
        self.stop_tracking()
paul@0 624
paul@1 625
        # Exit to the parent.
paul@0 626
paul@0 627
        self.exit_namespace()
paul@0 628
paul@0 629
        # Update flags.
paul@0 630
paul@0 631
        self.in_function = in_function
paul@0 632
        self.in_conditional = in_conditional
paul@0 633
paul@0 634
        # Define the function using the appropriate name.
paul@0 635
paul@0 636
        self.set_definition(name, "<function>")
paul@0 637
paul@0 638
        # Where a function is set conditionally, assign the name.
paul@0 639
paul@0 640
        if original_name:
paul@0 641
            self.process_assignment_for_function(original_name, name)
paul@0 642
paul@0 643
    def process_global_node(self, n):
paul@0 644
paul@0 645
        """
paul@0 646
        Process the given "global" node 'n'.
paul@0 647
        """
paul@0 648
paul@0 649
        path = self.get_namespace_path()
paul@0 650
paul@0 651
        if path != self.name:
paul@0 652
            self.scope_globals[path].update(n.names)
paul@0 653
paul@0 654
    def process_if_node(self, n):
paul@0 655
paul@0 656
        """
paul@0 657
        Process the given "if" node 'n'.
paul@0 658
        """
paul@0 659
paul@0 660
        tracker = self.trackers[-1]
paul@0 661
        tracker.new_branchpoint()
paul@0 662
paul@0 663
        for test, body in n.tests:
paul@0 664
            self.process_structure_node(test)
paul@0 665
paul@0 666
            tracker.new_branch()
paul@0 667
paul@0 668
            in_conditional = self.in_conditional
paul@0 669
            self.in_conditional = True
paul@0 670
            self.process_structure_node(body)
paul@0 671
            self.in_conditional = in_conditional
paul@0 672
paul@0 673
            tracker.shelve_branch()
paul@0 674
paul@0 675
        # Maintain a branch for the else clause.
paul@0 676
paul@0 677
        tracker.new_branch()
paul@0 678
        if n.else_:
paul@0 679
            self.process_structure_node(n.else_)
paul@0 680
        tracker.shelve_branch()
paul@0 681
paul@0 682
        tracker.merge_branches()
paul@0 683
paul@0 684
    def process_import_node(self, n):
paul@0 685
paul@0 686
        "Process the given import node 'n'."
paul@0 687
paul@0 688
        path = self.get_namespace_path()
paul@0 689
paul@0 690
        # Load the mentioned module.
paul@0 691
paul@0 692
        for name, alias in n.names:
paul@12 693
            if name == self.name:
paul@12 694
                raise InspectError("Cannot import the current module.", path, n)
paul@0 695
paul@13 696
            self.set_module(alias or name.split(".")[-1], name)
paul@18 697
            self.queue_module(name, True)
paul@0 698
paul@0 699
    def process_invocation_node(self, n):
paul@0 700
paul@0 701
        "Process the given invocation node 'n'."
paul@0 702
paul@0 703
        path = self.get_namespace_path()
paul@0 704
paul@0 705
        self.allocate_arguments(path, n.args)
paul@0 706
paul@0 707
        try:
paul@0 708
            # Process the expression, obtaining any identified reference.
paul@0 709
paul@0 710
            name_ref = self.process_structure_node(n.node)
paul@0 711
paul@0 712
            # Process the arguments.
paul@0 713
paul@0 714
            for arg in n.args:
paul@0 715
                self.process_structure_node(arg)
paul@0 716
paul@0 717
            # Detect class invocations.
paul@0 718
paul@0 719
            if isinstance(name_ref, ResolvedNameRef) and name_ref.has_kind("<class>"):
paul@0 720
                return InstanceRef(name_ref.reference().instance_of())
paul@0 721
paul@0 722
            elif isinstance(name_ref, NameRef):
paul@0 723
                return InvocationRef(name_ref)
paul@0 724
paul@0 725
            return None
paul@0 726
paul@0 727
        finally:
paul@0 728
            self.deallocate_arguments(path, n.args)
paul@0 729
paul@0 730
    def process_lambda_node(self, n):
paul@0 731
paul@0 732
        "Process the given lambda node 'n'."
paul@0 733
paul@0 734
        name = self.get_lambda_name()
paul@0 735
        self.process_function_node(n, name)
paul@0 736
paul@0 737
        origin = self.get_object_path(name)
paul@0 738
        return ResolvedNameRef(name, Reference("<function>", origin))
paul@0 739
paul@0 740
    def process_logical_node(self, n):
paul@0 741
paul@0 742
        "Process the given operator node 'n'."
paul@0 743
paul@0 744
        self.process_operator_chain(n.nodes, self.process_structure_node)
paul@0 745
paul@0 746
    def process_name_node(self, n):
paul@0 747
paul@0 748
        "Process the given name node 'n'."
paul@0 749
paul@0 750
        path = self.get_namespace_path()
paul@0 751
paul@0 752
        # Special names.
paul@0 753
paul@0 754
        if n.name.startswith("$"):
paul@0 755
            value = self.get_special(n.name)
paul@0 756
            if value:
paul@0 757
                return value
paul@0 758
paul@0 759
        # Special case for operator functions introduced through code
paul@0 760
        # transformations.
paul@0 761
paul@0 762
        if n.name.startswith("$op"):
paul@0 763
paul@0 764
            # Obtain the location of the actual function defined in the operator
paul@0 765
            # package.
paul@0 766
paul@0 767
            op = n.name[len("$op"):]
paul@0 768
paul@0 769
            # Attempt to get a reference.
paul@0 770
paul@12 771
            ref = self.import_name_from_module(op, "operator")
paul@35 772
            self.add_deferred(ref)
paul@0 773
paul@0 774
            # Record the imported name and provide the resolved name reference.
paul@0 775
paul@0 776
            value = ResolvedNameRef(n.name, ref)
paul@0 777
            self.set_special(n.name, value)
paul@0 778
            return value
paul@0 779
paul@60 780
        # Test for self usage, which is only allowed in methods.
paul@60 781
paul@60 782
        if n.name == "self" and not (self.in_function and self.in_class):
paul@60 783
            raise InspectError("Use of self is only allowed in methods.", path, n)
paul@60 784
paul@0 785
        # Record usage of the name.
paul@0 786
paul@0 787
        self.record_name(n.name)
paul@0 788
paul@0 789
        # Search for unknown names in non-function scopes immediately.
paul@0 790
        # External names in functions are resolved later.
paul@0 791
paul@0 792
        ref = self.find_name(n.name)
paul@0 793
        if ref:
paul@0 794
            return ResolvedNameRef(n.name, ref)
paul@0 795
paul@40 796
        # Explicitly-declared global names.
paul@0 797
paul@0 798
        elif self.in_function and n.name in self.scope_globals[path]:
paul@0 799
            return NameRef(n.name)
paul@0 800
paul@0 801
        # Examine other names.
paul@0 802
paul@0 803
        else:
paul@0 804
            tracker = self.trackers[-1]
paul@0 805
paul@0 806
            # Check local names.
paul@0 807
paul@0 808
            branches = tracker.tracking_name(n.name)
paul@0 809
paul@1 810
            # Local name.
paul@0 811
paul@0 812
            if branches:
paul@0 813
                self.record_branches_for_access(branches, n.name, None)
paul@0 814
                access_number = self.record_access_details(n.name, None, False)
paul@0 815
                return LocalNameRef(n.name, access_number)
paul@0 816
paul@40 817
            # Possible global or built-in name.
paul@0 818
paul@0 819
            else:
paul@0 820
                return NameRef(n.name)
paul@0 821
paul@0 822
    def process_operator_chain(self, nodes, fn):
paul@0 823
paul@0 824
        """
paul@0 825
        Process the given chain of 'nodes', applying 'fn' to each node or item.
paul@0 826
        Each node starts a new conditional region, effectively making a deeply-
paul@0 827
        nested collection of if-like statements.
paul@0 828
        """
paul@0 829
paul@0 830
        tracker = self.trackers[-1]
paul@0 831
paul@0 832
        for item in nodes:
paul@0 833
            tracker.new_branchpoint()
paul@0 834
            tracker.new_branch()
paul@0 835
            fn(item)
paul@0 836
paul@0 837
        for item in nodes[:-1]:
paul@0 838
            tracker.shelve_branch()
paul@0 839
            tracker.new_branch()
paul@0 840
            tracker.shelve_branch()
paul@0 841
            tracker.merge_branches()
paul@0 842
paul@0 843
        tracker.shelve_branch()
paul@0 844
        tracker.merge_branches()
paul@0 845
paul@0 846
    def process_try_node(self, n):
paul@0 847
paul@0 848
        """
paul@0 849
        Process the given "try...except" node 'n'.
paul@0 850
        """
paul@0 851
paul@0 852
        tracker = self.trackers[-1]
paul@0 853
        tracker.new_branchpoint()
paul@0 854
paul@0 855
        self.process_structure_node(n.body)
paul@0 856
paul@0 857
        for name, var, handler in n.handlers:
paul@0 858
            if name is not None:
paul@0 859
                self.process_structure_node(name)
paul@0 860
paul@0 861
            # Any abandoned branches from the body can now be resumed in a new
paul@0 862
            # branch.
paul@0 863
paul@0 864
            tracker.resume_abandoned_branches()
paul@0 865
paul@0 866
            # Establish the local for the handler.
paul@0 867
paul@0 868
            if var is not None:
paul@0 869
                self.process_structure_node(var)
paul@0 870
            if handler is not None:
paul@0 871
                self.process_structure_node(handler)
paul@0 872
paul@0 873
            tracker.shelve_branch()
paul@0 874
paul@0 875
        # The else clause maintains the usage from the body but without the
paul@0 876
        # abandoned branches since they would never lead to the else clause
paul@0 877
        # being executed.
paul@0 878
paul@0 879
        if n.else_:
paul@0 880
            tracker.new_branch()
paul@0 881
            self.process_structure_node(n.else_)
paul@0 882
            tracker.shelve_branch()
paul@0 883
paul@0 884
        # Without an else clause, a null branch propagates the successful
paul@0 885
        # outcome.
paul@0 886
paul@0 887
        else:
paul@0 888
            tracker.new_branch()
paul@0 889
            tracker.shelve_branch()
paul@0 890
paul@0 891
        tracker.merge_branches()
paul@0 892
paul@0 893
    def process_try_finally_node(self, n):
paul@0 894
paul@0 895
        """
paul@0 896
        Process the given "try...finally" node 'n'.
paul@0 897
        """
paul@0 898
paul@0 899
        tracker = self.trackers[-1]
paul@0 900
        self.process_structure_node(n.body)
paul@0 901
paul@0 902
        # Any abandoned branches from the body can now be resumed.
paul@0 903
paul@0 904
        branches = tracker.resume_all_abandoned_branches()
paul@0 905
        self.process_structure_node(n.final)
paul@0 906
paul@0 907
        # At the end of the finally clause, abandoned branches are discarded.
paul@0 908
paul@0 909
        tracker.restore_active_branches(branches)
paul@0 910
paul@0 911
    def process_while_node(self, n):
paul@0 912
paul@0 913
        "Process the given while node 'n'."
paul@0 914
paul@0 915
        tracker = self.trackers[-1]
paul@0 916
        tracker.new_branchpoint(loop_node=True)
paul@0 917
paul@0 918
        # Evaluate any test or iterator outside the loop.
paul@0 919
paul@0 920
        self.process_structure_node(n.test)
paul@0 921
paul@0 922
        # Propagate attribute usage to branches.
paul@0 923
paul@0 924
        tracker.new_branch(loop_node=True)
paul@0 925
paul@0 926
        # Enter the loop.
paul@0 927
paul@0 928
        in_conditional = self.in_conditional
paul@0 929
        self.in_conditional = True
paul@0 930
        self.process_structure_node(n.body)
paul@0 931
        self.in_conditional = in_conditional
paul@0 932
paul@0 933
        # Continuing branches are resumed before any test.
paul@0 934
paul@0 935
        tracker.resume_continuing_branches()
paul@0 936
paul@0 937
        # Evaluate any continuation test within the body.
paul@0 938
paul@0 939
        self.process_structure_node(n.test)
paul@0 940
paul@0 941
        tracker.shelve_branch(loop_node=True)
paul@0 942
paul@0 943
        # Support the non-looping condition.
paul@0 944
paul@0 945
        tracker.new_branch()
paul@0 946
        tracker.shelve_branch()
paul@0 947
paul@0 948
        tracker.merge_branches()
paul@0 949
paul@0 950
        # Evaluate any else clause outside branches.
paul@0 951
paul@0 952
        if n.else_:
paul@0 953
            self.process_structure_node(n.else_)
paul@0 954
paul@0 955
        # Connect broken branches to the code after any loop.
paul@0 956
paul@0 957
        tracker.resume_broken_branches()
paul@0 958
paul@0 959
    # Branch tracking methods.
paul@0 960
paul@0 961
    def start_tracking(self, names):
paul@0 962
paul@0 963
        """
paul@0 964
        Start tracking attribute usage for names in the current namespace,
paul@0 965
        immediately registering the given 'names'.
paul@0 966
        """
paul@0 967
paul@0 968
        path = self.get_namespace_path()
paul@0 969
        parent = self.trackers[-1]
paul@0 970
        tracker = BranchTracker()
paul@0 971
        self.trackers.append(tracker)
paul@0 972
paul@0 973
        # Record the given names established as new branches.
paul@0 974
paul@0 975
        tracker.assign_names(names)
paul@0 976
paul@0 977
    def assign_name(self, name, name_ref):
paul@0 978
paul@0 979
        "Assign to 'name' the given 'name_ref' in the current namespace."
paul@0 980
paul@0 981
        name = self.get_name_for_tracking(name)
paul@0 982
        self.trackers[-1].assign_names([name], [name_ref])
paul@0 983
paul@0 984
    def stop_tracking(self):
paul@0 985
paul@0 986
        """
paul@0 987
        Stop tracking attribute usage, recording computed usage for the current
paul@0 988
        namespace.
paul@0 989
        """
paul@0 990
paul@0 991
        path = self.get_namespace_path()
paul@0 992
        tracker = self.trackers.pop()
paul@0 993
        self.record_assignments_for_access(tracker)
paul@0 994
paul@0 995
        self.attr_usage[path] = tracker.get_all_usage()
paul@0 996
        self.name_initialisers[path] = tracker.get_all_values()
paul@0 997
paul@0 998
    def start_tracking_in_module(self):
paul@0 999
paul@0 1000
        "Start tracking attribute usage in the module."
paul@0 1001
paul@0 1002
        tracker = BranchTracker()
paul@0 1003
        self.trackers.append(tracker)
paul@0 1004
paul@0 1005
    def stop_tracking_in_module(self):
paul@0 1006
paul@0 1007
        "Stop tracking attribute usage in the module."
paul@0 1008
paul@0 1009
        tracker = self.trackers[0]
paul@0 1010
        self.record_assignments_for_access(tracker)
paul@0 1011
        self.attr_usage[self.name] = tracker.get_all_usage()
paul@0 1012
        self.name_initialisers[self.name] = tracker.get_all_values()
paul@0 1013
paul@0 1014
    def record_assignments_for_access(self, tracker):
paul@0 1015
paul@0 1016
        """
paul@0 1017
        For the current path, use the given 'tracker' to record assignment
paul@0 1018
        version information for attribute accesses.
paul@0 1019
        """
paul@0 1020
paul@0 1021
        path = self.get_path_for_access()
paul@0 1022
paul@0 1023
        if not self.attr_accessor_branches.has_key(path):
paul@0 1024
            return
paul@0 1025
paul@0 1026
        init_item(self.attr_accessors, path, dict)
paul@0 1027
        attr_accessors = self.attr_accessors[path]
paul@0 1028
paul@0 1029
        # Obtain the branches applying during each access.
paul@0 1030
paul@0 1031
        for access, all_branches in self.attr_accessor_branches[path].items():
paul@0 1032
            name, attrnames = access
paul@0 1033
            init_item(attr_accessors, access, list)
paul@0 1034
paul@0 1035
            # Obtain the assignments applying to each branch.
paul@0 1036
paul@0 1037
            for branches in all_branches:
paul@0 1038
                positions = tracker.get_assignment_positions_for_branches(name, branches)
paul@0 1039
paul@0 1040
                # Detect missing name information.
paul@0 1041
paul@0 1042
                if None in positions:
paul@0 1043
                    globals = self.global_attr_accesses.get(path)
paul@0 1044
                    accesses = globals and globals.get(name)
paul@0 1045
                    if not accesses:
paul@0 1046
                        print >>sys.stderr, "In %s, %s may not be defined when used." % (
paul@0 1047
                            self.get_namespace_path(), name)
paul@0 1048
                    positions.remove(None)
paul@0 1049
paul@0 1050
                attr_accessors[access].append(positions)
paul@0 1051
paul@0 1052
    def record_branches_for_access(self, branches, name, attrnames):
paul@0 1053
paul@0 1054
        """
paul@0 1055
        Record the given 'branches' for an access involving the given 'name' and
paul@0 1056
        'attrnames'.
paul@0 1057
        """
paul@0 1058
paul@0 1059
        access = name, attrnames
paul@0 1060
        path = self.get_path_for_access()
paul@0 1061
paul@0 1062
        init_item(self.attr_accessor_branches, path, dict)
paul@0 1063
        attr_accessor_branches = self.attr_accessor_branches[path]
paul@0 1064
paul@0 1065
        init_item(attr_accessor_branches, access, list)
paul@0 1066
        attr_accessor_branches[access].append(branches)
paul@0 1067
paul@0 1068
    def record_access_details(self, name, attrnames, assignment):
paul@0 1069
paul@0 1070
        """
paul@0 1071
        For the given 'name' and 'attrnames', record an access indicating
paul@0 1072
        whether 'assignment' is occurring.
paul@0 1073
paul@0 1074
        These details correspond to accesses otherwise recorded by the attribute
paul@0 1075
        accessor and attribute access dictionaries.
paul@0 1076
        """
paul@0 1077
paul@0 1078
        access = name, attrnames
paul@0 1079
        path = self.get_path_for_access()
paul@0 1080
paul@0 1081
        init_item(self.attr_access_modifiers, path, dict)
paul@0 1082
        init_item(self.attr_access_modifiers[path], access, list)
paul@0 1083
paul@0 1084
        access_number = len(self.attr_access_modifiers[path][access])
paul@0 1085
        self.attr_access_modifiers[path][access].append(assignment)
paul@0 1086
        return access_number
paul@0 1087
paul@0 1088
    def record_global_access_details(self, name, attrnames):
paul@0 1089
paul@0 1090
        """
paul@0 1091
        Record details of a global access via the given 'name' involving the
paul@0 1092
        indicated 'attrnames'.
paul@0 1093
        """
paul@0 1094
paul@0 1095
        path = self.get_namespace_path()
paul@0 1096
paul@0 1097
        init_item(self.global_attr_accesses, path, dict)
paul@0 1098
        init_item(self.global_attr_accesses[path], name, set)
paul@0 1099
        self.global_attr_accesses[path][name].add(attrnames)
paul@0 1100
paul@0 1101
    # Namespace modification.
paul@0 1102
paul@0 1103
    def record_name(self, name):
paul@0 1104
paul@0 1105
        "Record the use of 'name' in a namespace."
paul@0 1106
paul@0 1107
        path = self.get_namespace_path()
paul@0 1108
        init_item(self.names_used, path, set)
paul@0 1109
        self.names_used[path].add(name)
paul@0 1110
paul@12 1111
    def set_module(self, name, module_name):
paul@0 1112
paul@0 1113
        """
paul@12 1114
        Set a module in the current namespace using the given 'name' associated
paul@12 1115
        with the corresponding 'module_name'.
paul@0 1116
        """
paul@0 1117
paul@0 1118
        if name:
paul@12 1119
            self.set_general_local(name, Reference("<module>", module_name))
paul@0 1120
paul@0 1121
    def set_definition(self, name, kind):
paul@0 1122
paul@0 1123
        """
paul@0 1124
        Set the definition having the given 'name' and 'kind'.
paul@0 1125
paul@0 1126
        Definitions are set in the static namespace hierarchy, but they can also
paul@0 1127
        be recorded for function locals.
paul@0 1128
        """
paul@0 1129
paul@0 1130
        if self.is_global(name):
paul@0 1131
            print >>sys.stderr, "In %s, %s is defined as being global." % (
paul@0 1132
                self.get_namespace_path(), name)
paul@0 1133
paul@0 1134
        path = self.get_object_path(name)
paul@0 1135
        self.set_object(path, kind)
paul@0 1136
paul@0 1137
        ref = self.get_object(path)
paul@0 1138
        if ref.get_kind() == "<var>":
paul@0 1139
            print >>sys.stderr, "In %s, %s is defined more than once." % (
paul@0 1140
                self.get_namespace_path(), name)
paul@0 1141
paul@0 1142
        if not self.is_global(name) and self.in_function:
paul@0 1143
            self.set_function_local(name, ref)
paul@0 1144
paul@0 1145
    def set_function_local(self, name, ref=None):
paul@0 1146
paul@0 1147
        "Set the local with the given 'name' and optional 'ref'."
paul@0 1148
paul@0 1149
        locals = self.function_locals[self.get_namespace_path()]
paul@0 1150
        multiple = not ref or locals.has_key(name) and locals[name] != ref
paul@0 1151
        locals[name] = multiple and Reference("<var>") or ref
paul@0 1152
paul@0 1153
    def assign_general_local(self, name, name_ref):
paul@0 1154
paul@0 1155
        """
paul@0 1156
        Set for 'name' the given 'name_ref', recording the name for attribute
paul@0 1157
        usage tracking.
paul@0 1158
        """
paul@0 1159
paul@0 1160
        self.set_general_local(name, name_ref)
paul@0 1161
        self.assign_name(name, name_ref)
paul@0 1162
paul@0 1163
    def set_general_local(self, name, value=None):
paul@0 1164
paul@0 1165
        """
paul@0 1166
        Set the 'name' with optional 'value' in any kind of local namespace,
paul@0 1167
        where the 'value' should be a reference if specified.
paul@0 1168
        """
paul@0 1169
paul@0 1170
        init_value = self.get_initialising_value(value)
paul@0 1171
paul@0 1172
        # Module global names.
paul@0 1173
paul@0 1174
        if self.is_global(name):
paul@0 1175
            path = self.get_global_path(name)
paul@0 1176
            self.set_object(path, init_value)
paul@0 1177
paul@0 1178
        # Function local names.
paul@0 1179
paul@0 1180
        elif self.in_function:
paul@0 1181
            path = self.get_object_path(name)
paul@0 1182
            self.set_function_local(name, init_value)
paul@0 1183
paul@0 1184
        # Other namespaces (classes).
paul@0 1185
paul@0 1186
        else:
paul@0 1187
            path = self.get_object_path(name)
paul@0 1188
            self.set_name(name, init_value)
paul@0 1189
paul@0 1190
    def set_name(self, name, ref=None):
paul@0 1191
paul@0 1192
        "Attach the 'name' with optional 'ref' to the current namespace."
paul@0 1193
paul@0 1194
        self.set_object(self.get_object_path(name), ref)
paul@0 1195
paul@0 1196
    def set_instance_attr(self, name, ref=None):
paul@0 1197
paul@0 1198
        """
paul@0 1199
        Add an instance attribute of the given 'name' to the current class,
paul@0 1200
        using the optional 'ref'.
paul@0 1201
        """
paul@0 1202
paul@0 1203
        init_item(self.instance_attrs, self.in_class, set)
paul@0 1204
        self.instance_attrs[self.in_class].add(name)
paul@0 1205
paul@0 1206
        if ref:
paul@0 1207
            init_item(self.instance_attr_constants, self.in_class, dict)
paul@0 1208
            self.instance_attr_constants[self.in_class][name] = ref
paul@0 1209
paul@0 1210
    def get_initialising_value(self, value):
paul@0 1211
paul@0 1212
        "Return a suitable initialiser reference for 'value'."
paul@0 1213
paul@25 1214
        # Includes LiteralSequenceRef, ResolvedNameRef...
paul@25 1215
paul@25 1216
        if isinstance(value, (NameRef, AccessRef, InstanceRef)):
paul@0 1217
            return value.reference()
paul@0 1218
paul@0 1219
        # In general, invocations do not produce known results. However, the
paul@0 1220
        # name initialisers are resolved once a module has been inspected.
paul@0 1221
paul@0 1222
        elif isinstance(value, InvocationRef):
paul@27 1223
            return value.reference()
paul@0 1224
paul@0 1225
        else:
paul@0 1226
            return value
paul@0 1227
paul@0 1228
    # Static, program-relative naming.
paul@0 1229
paul@0 1230
    def find_name(self, name):
paul@0 1231
paul@0 1232
        """
paul@0 1233
        Return the qualified name for the given 'name' used in the current
paul@0 1234
        non-function namespace.
paul@0 1235
        """
paul@0 1236
paul@0 1237
        path = self.get_namespace_path()
paul@0 1238
        ref = None
paul@0 1239
paul@0 1240
        if not self.in_function and name not in predefined_constants:
paul@0 1241
            if self.in_class:
paul@0 1242
                ref = self.get_object(self.get_object_path(name))
paul@0 1243
            if not ref:
paul@0 1244
                ref = self.get_global_or_builtin(name)
paul@0 1245
paul@0 1246
        return ref
paul@0 1247
paul@0 1248
    def get_class(self, node):
paul@0 1249
paul@0 1250
        """
paul@0 1251
        Use the given 'node' to obtain the identity of a class. Return a
paul@0 1252
        reference for the class. Unresolved dependencies are permitted and must
paul@0 1253
        be resolved later.
paul@0 1254
        """
paul@0 1255
paul@0 1256
        ref = self._get_class(node)
paul@0 1257
        return ref.has_kind(["<class>", "<depends>"]) and ref or None
paul@0 1258
paul@0 1259
    def _get_class(self, node):
paul@0 1260
paul@0 1261
        """
paul@0 1262
        Use the given 'node' to find a class definition. Return a reference to
paul@0 1263
        the class.
paul@0 1264
        """
paul@0 1265
paul@0 1266
        if isinstance(node, compiler.ast.Getattr):
paul@0 1267
paul@0 1268
            # Obtain the identity of the access target.
paul@0 1269
paul@0 1270
            ref = self._get_class(node.expr)
paul@0 1271
paul@0 1272
            # Where the target is a class or module, obtain the identity of the
paul@0 1273
            # attribute.
paul@0 1274
paul@0 1275
            if ref.has_kind(["<function>", "<var>"]):
paul@0 1276
                return None
paul@0 1277
            else:
paul@0 1278
                attrname = "%s.%s" % (ref.get_origin(), node.attrname)
paul@0 1279
                return self.get_object(attrname)
paul@0 1280
paul@0 1281
        # Names can be module-level or built-in.
paul@0 1282
paul@0 1283
        elif isinstance(node, compiler.ast.Name):
paul@0 1284
paul@0 1285
            # Record usage of the name and attempt to identify it.
paul@0 1286
paul@0 1287
            self.record_name(node.name)
paul@73 1288
            return self.find_name(node.name)
paul@0 1289
        else:
paul@0 1290
            return None
paul@0 1291
paul@0 1292
    def get_constant(self, name, value):
paul@0 1293
paul@0 1294
        "Return a constant reference for the given type 'name' and 'value'."
paul@0 1295
paul@12 1296
        ref = self.get_builtin_class(name)
paul@0 1297
        return self.get_constant_reference(ref, value)
paul@0 1298
paul@0 1299
    def get_literal_instance(self, n, name):
paul@0 1300
paul@0 1301
        "For node 'n', return a reference to an instance of 'name'."
paul@0 1302
paul@12 1303
        # Get a reference to the built-in class.
paul@0 1304
paul@12 1305
        ref = self.get_builtin_class(name)
paul@0 1306
paul@0 1307
        # Obtain the details of the literal itself.
paul@0 1308
        # An alias to the type is generated for sequences.
paul@0 1309
paul@0 1310
        if name in ("dict", "list", "tuple"):
paul@0 1311
            self.set_special_literal(name, ref)
paul@0 1312
            return self.process_literal_sequence_node(n, name, ref, LiteralSequenceRef)
paul@0 1313
paul@0 1314
        # Constant values are independently recorded.
paul@0 1315
paul@0 1316
        else:
paul@0 1317
            return self.get_constant_reference(ref, n.value)
paul@0 1318
paul@17 1319
    # Special names.
paul@0 1320
paul@17 1321
    def get_special(self, name):
paul@0 1322
paul@17 1323
        "Return any stored value for the given special 'name'."
paul@0 1324
paul@17 1325
        return self.special.get(name)
paul@17 1326
paul@17 1327
    def set_special(self, name, value):
paul@0 1328
paul@17 1329
        """
paul@17 1330
        Set a special 'name' that merely tracks the use of an implicit object
paul@17 1331
        'value'.
paul@17 1332
        """
paul@0 1333
paul@17 1334
        self.special[name] = value
paul@17 1335
paul@17 1336
    def set_special_literal(self, name, ref):
paul@0 1337
paul@17 1338
        """
paul@17 1339
        Set a special name for the literal type 'name' having type 'ref'. Such
paul@17 1340
        special names provide a way of referring to literal object types.
paul@17 1341
        """
paul@0 1342
paul@17 1343
        literal_name = "$L%s" % name
paul@17 1344
        value = ResolvedNameRef(literal_name, ref)
paul@17 1345
        self.set_special(literal_name, value)
paul@0 1346
paul@0 1347
    # Functions and invocations.
paul@0 1348
paul@36 1349
    def set_invocation_usage(self):
paul@36 1350
paul@36 1351
        """
paul@36 1352
        Discard the current invocation storage figures, retaining the maximum
paul@36 1353
        values.
paul@36 1354
        """
paul@36 1355
paul@36 1356
        for path, (current, maximum) in self.function_targets.items():
paul@36 1357
            self.importer.function_targets[path] = self.function_targets[path] = maximum
paul@36 1358
paul@36 1359
        for path, (current, maximum) in self.function_arguments.items():
paul@36 1360
            self.importer.function_arguments[path] = self.function_arguments[path] = maximum
paul@36 1361
paul@0 1362
    def allocate_arguments(self, path, args):
paul@0 1363
paul@0 1364
        """
paul@0 1365
        Allocate temporary argument storage using current and maximum
paul@0 1366
        requirements for the given 'path' and 'args'.
paul@0 1367
        """
paul@0 1368
paul@0 1369
        init_item(self.function_targets, path, lambda: [0, 0])
paul@0 1370
        t = self.function_targets[path]
paul@0 1371
        t[0] += 1
paul@0 1372
        t[1] = max(t[0], t[1])
paul@0 1373
paul@0 1374
        init_item(self.function_arguments, path, lambda: [0, 0])
paul@0 1375
        t = self.function_arguments[path]
paul@0 1376
        t[0] += len(args) + 1
paul@0 1377
        t[1] = max(t[0], t[1])
paul@0 1378
paul@0 1379
    def deallocate_arguments(self, path, args):
paul@0 1380
paul@0 1381
        "Deallocate temporary argument storage for the given 'path' and 'args'."
paul@0 1382
paul@0 1383
        self.function_targets[path][0] -= 1
paul@0 1384
        self.function_arguments[path][0] -= len(args) + 1
paul@0 1385
paul@0 1386
# vim: tabstop=4 expandtab shiftwidth=4