Lichen

Annotated common.py

543:b7334adb7dec
2017-02-04 Paul Boddie Handle situations where a global accidentally refers to a built-in module.
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#!/usr/bin/env python
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"""
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Common functions.
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Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013,
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              2014, 2015, 2016, 2017 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 compiler.transformer import Transformer
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from errors import InspectError
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from os import listdir, makedirs, remove
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from os.path import exists, isdir, join, split
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from results import ConstantValueRef, LiteralSequenceRef, NameRef
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import compiler.ast
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class CommonOutput:
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    "Common output functionality."
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    def check_output(self):
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        "Check the existing output and remove it if irrelevant."
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        if not exists(self.output):
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            makedirs(self.output)
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        details = self.importer.get_cache_details()
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        recorded_details = self.get_output_details()
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        if recorded_details != details:
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            self.remove_output()
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        writefile(self.get_output_details_filename(), details)
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    def get_output_details_filename(self):
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        "Return the output details filename."
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        return join(self.output, "$details")
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    def get_output_details(self):
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        "Return details of the existing output."
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        details_filename = self.get_output_details_filename()
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        if not exists(details_filename):
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            return None
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        else:
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            return readfile(details_filename)
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    def remove_output(self, dirname=None):
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        "Remove the output."
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        dirname = dirname or self.output
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        for filename in listdir(dirname):
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            path = join(dirname, filename)
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            if isdir(path):
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                self.remove_output(path)
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            else:
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                remove(path)
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class CommonModule:
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    "A common module representation."
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    def __init__(self, name, importer):
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        """
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        Initialise this module with the given 'name' and an 'importer' which is
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        used to provide access to other modules when required.
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        """
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        self.name = name
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        self.importer = importer
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        self.filename = None
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        # Inspection-related attributes.
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        self.astnode = None
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        self.encoding = None
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        self.iterators = {}
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        self.temp = {}
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        self.lambdas = {}
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        # Constants, literals and values.
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        self.constants = {}
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        self.constant_values = {}
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        self.literals = {}
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        self.literal_types = {}
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        # Nested namespaces.
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        self.namespace_path = []
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        self.in_function = False
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        # Retain the assignment value expression and track invocations.
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        self.in_assignment = None
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        self.in_invocation = False
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        # Attribute chain state management.
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        self.attrs = []
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        self.chain_assignment = []
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        self.chain_invocation = []
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    def __repr__(self):
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        return "CommonModule(%r, %r)" % (self.name, self.importer)
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    def parse_file(self, filename):
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        "Parse the file with the given 'filename', initialising attributes."
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        self.filename = filename
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        # Use the Transformer directly to obtain encoding information.
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        t = Transformer()
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        f = open(filename)
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        try:
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            self.astnode = t.parsesuite(f.read() + "\n")
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            self.encoding = t.encoding
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        finally:
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            f.close()
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    # Module-relative naming.
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    def get_global_path(self, name):
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        return "%s.%s" % (self.name, name)
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    def get_namespace_path(self):
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        return ".".join([self.name] + self.namespace_path)
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    def get_object_path(self, name):
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        return ".".join([self.name] + self.namespace_path + [name])
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    def get_parent_path(self):
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        return ".".join([self.name] + self.namespace_path[:-1])
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    # Namespace management.
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    def enter_namespace(self, name):
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        "Enter the namespace having the given 'name'."
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        self.namespace_path.append(name)
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    def exit_namespace(self):
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        "Exit the current namespace."
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        self.namespace_path.pop()
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    # Constant reference naming.
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    def get_constant_name(self, value, value_type, encoding=None):
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        """
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        Add a new constant to the current namespace for 'value' with
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        'value_type'.
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        """
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        path = self.get_namespace_path()
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        init_item(self.constants, path, dict)
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        return "$c%d" % add_counter_item(self.constants[path], (value, value_type, encoding))
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    # Literal reference naming.
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    def get_literal_name(self):
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        "Add a new literal to the current namespace."
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        path = self.get_namespace_path()
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        init_item(self.literals, path, lambda: 0)
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        return "$C%d" % self.literals[path]
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    def next_literal(self):
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        self.literals[self.get_namespace_path()] += 1
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    # Temporary iterator naming.
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    def get_iterator_path(self):
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        return self.in_function and self.get_namespace_path() or self.name
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    def get_iterator_name(self):
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        path = self.get_iterator_path()
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        init_item(self.iterators, path, lambda: 0)
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        return "$i%d" % self.iterators[path]
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    def next_iterator(self):
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        self.iterators[self.get_iterator_path()] += 1
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    # Temporary variable naming.
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    def get_temporary_name(self):
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        path = self.get_namespace_path()
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        init_item(self.temp, path, lambda: 0)
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        return "$t%d" % self.temp[path]
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    def next_temporary(self):
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        self.temp[self.get_namespace_path()] += 1
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    # Arbitrary function naming.
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    def get_lambda_name(self):
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        path = self.get_namespace_path()
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        init_item(self.lambdas, path, lambda: 0)
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        name = "$l%d" % self.lambdas[path]
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        self.lambdas[path] += 1
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        return name
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    def reset_lambdas(self):
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        self.lambdas = {}
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    # Constant and literal recording.
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    def get_constant_value(self, value, literals=None):
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        """
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        Encode the 'value' if appropriate, returning a value, a typename and any
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        encoding.
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        """
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        if isinstance(value, unicode):
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            return value.encode("utf-8"), "unicode", self.encoding
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        # Attempt to convert plain strings to text.
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        elif isinstance(value, str) and self.encoding:
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            try:
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                return get_string_details(literals, self.encoding)
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            except UnicodeDecodeError:
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                pass
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        return value, value.__class__.__name__, None
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    def get_constant_reference(self, ref, value, encoding=None):
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        """
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        Return a constant reference for the given 'ref' type and 'value', with
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        the optional 'encoding' applying to text values.
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        """
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        constant_name = self.get_constant_name(value, ref.get_origin(), encoding)
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        # Return a reference for the constant.
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        objpath = self.get_object_path(constant_name)
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        name_ref = ConstantValueRef(constant_name, ref.instance_of(objpath), value)
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        # Record the value and type for the constant.
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        self._reserve_constant(objpath, name_ref.value, name_ref.get_origin(), encoding)
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        return name_ref
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    def reserve_constant(self, objpath, value, origin, encoding=None):
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        """
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        Reserve a constant within 'objpath' with the given 'value' and having a
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        type with the given 'origin', with the optional 'encoding' applying to
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        text values.
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        """
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        constant_name = self.get_constant_name(value, origin)
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        objpath = self.get_object_path(constant_name)
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        self._reserve_constant(objpath, value, origin, encoding)
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    def _reserve_constant(self, objpath, value, origin, encoding):
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        """
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        Store a constant for 'objpath' with the given 'value' and 'origin', with
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        the optional 'encoding' applying to text values.
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        """
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        self.constant_values[objpath] = value, origin, encoding
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    def get_literal_reference(self, name, ref, items, cls):
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        """
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        Return a literal reference for the given type 'name', literal 'ref',
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        node 'items' and employing the given 'cls' as the class of the returned
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        reference object.
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        """
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        # Construct an invocation using the items as arguments.
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        typename = "$L%s" % name
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        invocation = compiler.ast.CallFunc(
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            compiler.ast.Name(typename),
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            items
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            )
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        # Get a name for the actual literal.
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        instname = self.get_literal_name()
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        self.next_literal()
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        # Record the type for the literal.
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        objpath = self.get_object_path(instname)
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        self.literal_types[objpath] = ref.get_origin()
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        # Return a wrapper for the invocation exposing the items.
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        return cls(
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            instname,
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            ref.instance_of(),
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            self.process_structure_node(invocation),
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            invocation.args
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            )
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    # Node handling.
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    def process_structure(self, node):
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        """
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        Within the given 'node', process the program structure.
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        During inspection, this will process global declarations, adjusting the
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        module namespace, and import statements, building a module dependency
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        hierarchy.
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        During translation, this will consult deduced program information and
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        output translated code.
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        """
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        l = []
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        for n in node.getChildNodes():
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            l.append(self.process_structure_node(n))
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        return l
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    def process_augassign_node(self, n):
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        "Process the given augmented assignment node 'n'."
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        op = operator_functions[n.op]
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        if isinstance(n.node, compiler.ast.Getattr):
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            target = compiler.ast.AssAttr(n.node.expr, n.node.attrname, "OP_ASSIGN")
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        elif isinstance(n.node, compiler.ast.Name):
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            target = compiler.ast.AssName(n.node.name, "OP_ASSIGN")
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        else:
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            target = n.node
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        assignment = compiler.ast.Assign(
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            [target],
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            compiler.ast.CallFunc(
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                compiler.ast.Name("$op%s" % op),
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                [n.node, n.expr]))
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        return self.process_structure_node(assignment)
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    def process_assignment_for_object(self, original_name, source):
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        """
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        Return an assignment operation making 'original_name' refer to the given
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        'source'.
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        """
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        assignment = compiler.ast.Assign(
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            [compiler.ast.AssName(original_name, "OP_ASSIGN")],
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            source
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            )
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        return self.process_structure_node(assignment)
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    def process_assignment_node_items(self, n, expr):
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        """
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        Process the given assignment node 'n' whose children are to be assigned
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        items of 'expr'.
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        """
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        name_ref = self.process_structure_node(expr)
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        # Either unpack the items and present them directly to each assignment
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        # node.
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        if isinstance(name_ref, LiteralSequenceRef) and \
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           self.process_literal_sequence_items(n, name_ref):
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            pass
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        # Or have the assignment nodes access each item via the sequence API.
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        else:
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            self.process_assignment_node_items_by_position(n, expr, name_ref)
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    def process_assignment_node_items_by_position(self, n, expr, name_ref):
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        """
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        Process the given sequence assignment node 'n', converting the node to
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        the separate assignment of each target using positional access on a
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        temporary variable representing the sequence. Use 'expr' as the assigned
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        value and 'name_ref' as the reference providing any existing temporary
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        variable.
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        """
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        assignments = []
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        # Employ existing names to access the sequence.
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        # Literal sequences do not provide names of accessible objects.
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        if isinstance(name_ref, NameRef) and not isinstance(name_ref, LiteralSequenceRef):
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            temp = name_ref.name
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        # For other expressions, create a temporary name to reference the items.
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        else:
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            temp = self.get_temporary_name()
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            self.next_temporary()
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            assignments.append(
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                compiler.ast.Assign([compiler.ast.AssName(temp, "OP_ASSIGN")], expr)
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                )
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        # Assign the items to the target nodes.
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        for i, node in enumerate(n.nodes):
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            assignments.append(
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                compiler.ast.Assign([node], compiler.ast.Subscript(
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                    compiler.ast.Name(temp), "OP_APPLY", [compiler.ast.Const(i, str(i))]))
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                )
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        return self.process_structure_node(compiler.ast.Stmt(assignments))
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    def process_literal_sequence_items(self, n, name_ref):
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        """
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        Process the given assignment node 'n', obtaining from the given
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        'name_ref' the items to be assigned to the assignment targets.
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        Return whether this method was able to process the assignment node as
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        a sequence of direct assignments.
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        """
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        if len(n.nodes) == len(name_ref.items):
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            assigned_names, count = get_names_from_nodes(n.nodes)
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            accessed_names, _count = get_names_from_nodes(name_ref.items)
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            # Only assign directly between items if all assigned names are
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            # plain names (not attribute assignments), and if the assigned names
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            # do not appear in the accessed names.
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            if len(assigned_names) == count and \
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               not assigned_names.intersection(accessed_names):
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                for node, item in zip(n.nodes, name_ref.items):
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                    self.process_assignment_node(node, item)
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                return True
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            # Otherwise, use the position-based mechanism to obtain values.
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            else:
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                return False
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        else:
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            raise InspectError("In %s, item assignment needing %d items is given %d items." % (
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                self.get_namespace_path(), len(n.nodes), len(name_ref.items)))
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    def process_compare_node(self, n):
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        """
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        Process the given comparison node 'n', converting an operator sequence
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        from...
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        <expr1> <op1> <expr2> <op2> <expr3>
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        ...to...
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        <op1>(<expr1>, <expr2>) and <op2>(<expr2>, <expr3>)
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        """
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        invocations = []
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        last = n.expr
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        for op, op_node in n.ops:
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            op = operator_functions.get(op)
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            invocations.append(compiler.ast.CallFunc(
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                compiler.ast.Name("$op%s" % op),
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                [last, op_node]))
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            last = op_node
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        if len(invocations) > 1:
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            result = compiler.ast.And(invocations)
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        else:
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            result = invocations[0]
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        return self.process_structure_node(result)
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    def process_dict_node(self, node):
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        """
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        Process the given dictionary 'node', returning a list of (key, value)
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        tuples.
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        """
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        l = []
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        for key, value in node.items:
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            l.append((
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                self.process_structure_node(key),
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                self.process_structure_node(value)))
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        return l
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    def process_for_node(self, n):
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        """
paul@0 530
        Generate attribute accesses for {n.list}.__iter__ and the next method on
paul@0 531
        the iterator, producing a replacement node for the original.
paul@0 532
        """
paul@0 533
paul@0 534
        node = compiler.ast.Stmt([
paul@0 535
paul@533 536
            # <next> = {n.list}.__iter__().next
paul@0 537
paul@0 538
            compiler.ast.Assign(
paul@0 539
                [compiler.ast.AssName(self.get_iterator_name(), "OP_ASSIGN")],
paul@533 540
                compiler.ast.Getattr(
paul@533 541
                    compiler.ast.CallFunc(
paul@533 542
                        compiler.ast.Getattr(n.list, "__iter__"),
paul@533 543
                        []
paul@533 544
                        ), "next")),
paul@0 545
paul@0 546
            # try:
paul@0 547
            #     while True:
paul@533 548
            #         <var>... = <next>()
paul@0 549
            #         ...
paul@0 550
            # except StopIteration:
paul@0 551
            #     pass
paul@0 552
paul@0 553
            compiler.ast.TryExcept(
paul@0 554
                compiler.ast.While(
paul@0 555
                    compiler.ast.Name("True"),
paul@0 556
                    compiler.ast.Stmt([
paul@0 557
                        compiler.ast.Assign(
paul@0 558
                            [n.assign],
paul@0 559
                            compiler.ast.CallFunc(
paul@533 560
                                compiler.ast.Name(self.get_iterator_name()),
paul@0 561
                                []
paul@0 562
                                )),
paul@0 563
                        n.body]),
paul@0 564
                    None),
paul@0 565
                [(compiler.ast.Name("StopIteration"), None, compiler.ast.Stmt([compiler.ast.Pass()]))],
paul@0 566
                None)
paul@0 567
            ])
paul@0 568
paul@0 569
        self.next_iterator()
paul@0 570
        self.process_structure_node(node)
paul@0 571
paul@0 572
    def process_literal_sequence_node(self, n, name, ref, cls):
paul@0 573
paul@0 574
        """
paul@0 575
        Process the given literal sequence node 'n' as a function invocation,
paul@0 576
        with 'name' indicating the type of the sequence, and 'ref' being a
paul@0 577
        reference to the type. The 'cls' is used to instantiate a suitable name
paul@0 578
        reference.
paul@0 579
        """
paul@0 580
paul@0 581
        if name == "dict":
paul@0 582
            items = []
paul@0 583
            for key, value in n.items:
paul@0 584
                items.append(compiler.ast.Tuple([key, value]))
paul@0 585
        else: # name in ("list", "tuple"):
paul@0 586
            items = n.nodes
paul@0 587
paul@0 588
        return self.get_literal_reference(name, ref, items, cls)
paul@0 589
paul@0 590
    def process_operator_node(self, n):
paul@0 591
paul@0 592
        """
paul@0 593
        Process the given operator node 'n' as an operator function invocation.
paul@0 594
        """
paul@0 595
paul@0 596
        op = operator_functions[n.__class__.__name__]
paul@0 597
        invocation = compiler.ast.CallFunc(
paul@0 598
            compiler.ast.Name("$op%s" % op),
paul@0 599
            list(n.getChildNodes())
paul@0 600
            )
paul@0 601
        return self.process_structure_node(invocation)
paul@0 602
paul@173 603
    def process_print_node(self, n):
paul@173 604
paul@173 605
        """
paul@173 606
        Process the given print node 'n' as an invocation on a stream of the
paul@173 607
        form...
paul@173 608
paul@173 609
        $print(dest, args, nl)
paul@173 610
paul@173 611
        The special function name will be translated elsewhere.
paul@173 612
        """
paul@173 613
paul@173 614
        nl = isinstance(n, compiler.ast.Printnl)
paul@173 615
        invocation = compiler.ast.CallFunc(
paul@173 616
            compiler.ast.Name("$print"),
paul@173 617
            [n.dest or compiler.ast.Name("None"),
paul@173 618
             compiler.ast.List(list(n.nodes)),
paul@359 619
             nl and compiler.ast.Name("True") or compiler.ast.Name("False")]
paul@173 620
            )
paul@173 621
        return self.process_structure_node(invocation)
paul@173 622
paul@0 623
    def process_slice_node(self, n, expr=None):
paul@0 624
paul@0 625
        """
paul@0 626
        Process the given slice node 'n' as an operator function invocation.
paul@0 627
        """
paul@0 628
paul@0 629
        op = n.flags == "OP_ASSIGN" and "setslice" or "getslice"
paul@0 630
        invocation = compiler.ast.CallFunc(
paul@0 631
            compiler.ast.Name("$op%s" % op),
paul@0 632
            [n.expr, n.lower or compiler.ast.Name("None"), n.upper or compiler.ast.Name("None")] +
paul@0 633
                (expr and [expr] or [])
paul@0 634
            )
paul@0 635
        return self.process_structure_node(invocation)
paul@0 636
paul@0 637
    def process_sliceobj_node(self, n):
paul@0 638
paul@0 639
        """
paul@0 640
        Process the given slice object node 'n' as a slice constructor.
paul@0 641
        """
paul@0 642
paul@0 643
        op = "slice"
paul@0 644
        invocation = compiler.ast.CallFunc(
paul@0 645
            compiler.ast.Name("$op%s" % op),
paul@0 646
            n.nodes
paul@0 647
            )
paul@0 648
        return self.process_structure_node(invocation)
paul@0 649
paul@0 650
    def process_subscript_node(self, n, expr=None):
paul@0 651
paul@0 652
        """
paul@0 653
        Process the given subscript node 'n' as an operator function invocation.
paul@0 654
        """
paul@0 655
paul@0 656
        op = n.flags == "OP_ASSIGN" and "setitem" or "getitem"
paul@0 657
        invocation = compiler.ast.CallFunc(
paul@0 658
            compiler.ast.Name("$op%s" % op),
paul@0 659
            [n.expr] + list(n.subs) + (expr and [expr] or [])
paul@0 660
            )
paul@0 661
        return self.process_structure_node(invocation)
paul@0 662
paul@0 663
    def process_attribute_chain(self, n):
paul@0 664
paul@0 665
        """
paul@0 666
        Process the given attribute access node 'n'. Return a reference
paul@0 667
        describing the expression.
paul@0 668
        """
paul@0 669
paul@0 670
        # AssAttr/Getattr are nested with the outermost access being the last
paul@0 671
        # access in any chain.
paul@0 672
paul@0 673
        self.attrs.insert(0, n.attrname)
paul@0 674
        attrs = self.attrs
paul@0 675
paul@0 676
        # Break attribute chains where non-access nodes are found.
paul@0 677
paul@0 678
        if not self.have_access_expression(n):
paul@110 679
            self.reset_attribute_chain()
paul@0 680
paul@0 681
        # Descend into the expression, extending backwards any existing chain,
paul@0 682
        # or building another for the expression.
paul@0 683
paul@0 684
        name_ref = self.process_structure_node(n.expr)
paul@0 685
paul@0 686
        # Restore chain information applying to this node.
paul@0 687
paul@110 688
        if not self.have_access_expression(n):
paul@110 689
            self.restore_attribute_chain(attrs)
paul@0 690
paul@0 691
        # Return immediately if the expression was another access and thus a
paul@0 692
        # continuation backwards along the chain. The above processing will
paul@0 693
        # have followed the chain all the way to its conclusion.
paul@0 694
paul@0 695
        if self.have_access_expression(n):
paul@0 696
            del self.attrs[0]
paul@0 697
paul@0 698
        return name_ref
paul@0 699
paul@124 700
    # Attribute chain handling.
paul@124 701
paul@110 702
    def reset_attribute_chain(self):
paul@110 703
paul@110 704
        "Reset the attribute chain for a subexpression of an attribute access."
paul@110 705
paul@110 706
        self.attrs = []
paul@124 707
        self.chain_assignment.append(self.in_assignment)
paul@124 708
        self.chain_invocation.append(self.in_invocation)
paul@124 709
        self.in_assignment = None
paul@124 710
        self.in_invocation = False
paul@110 711
paul@110 712
    def restore_attribute_chain(self, attrs):
paul@110 713
paul@110 714
        "Restore the attribute chain for an attribute access."
paul@110 715
paul@110 716
        self.attrs = attrs
paul@124 717
        self.in_assignment = self.chain_assignment.pop()
paul@124 718
        self.in_invocation = self.chain_invocation.pop()
paul@110 719
paul@0 720
    def have_access_expression(self, node):
paul@0 721
paul@0 722
        "Return whether the expression associated with 'node' is Getattr."
paul@0 723
paul@0 724
        return isinstance(node.expr, compiler.ast.Getattr)
paul@0 725
paul@0 726
    def get_name_for_tracking(self, name, path=None):
paul@0 727
paul@0 728
        """
paul@0 729
        Return the name to be used for attribute usage observations involving
paul@0 730
        the given 'name' in the current namespace. If 'path' is indicated and
paul@0 731
        the name is being used outside a function, return the path value;
paul@0 732
        otherwise, return a path computed using the current namespace and the
paul@0 733
        given name.
paul@0 734
paul@0 735
        The intention of this method is to provide a suitably-qualified name
paul@0 736
        that can be tracked across namespaces. Where globals are being
paul@0 737
        referenced in class namespaces, they should be referenced using their
paul@0 738
        path within the module, not using a path within each class.
paul@0 739
paul@0 740
        It may not be possible to identify a global within a function at the
paul@0 741
        time of inspection (since a global may appear later in a file).
paul@0 742
        Consequently, globals are identified by their local name rather than
paul@0 743
        their module-qualified path.
paul@0 744
        """
paul@0 745
paul@0 746
        # For functions, use the appropriate local names.
paul@0 747
paul@0 748
        if self.in_function:
paul@0 749
            return name
paul@0 750
paul@0 751
        # For static namespaces, use the given qualified name.
paul@0 752
paul@0 753
        elif path:
paul@0 754
            return path
paul@0 755
paul@152 756
        # Otherwise, establish a name in the current namespace.
paul@0 757
paul@0 758
        else:
paul@0 759
            return self.get_object_path(name)
paul@0 760
paul@0 761
    def get_path_for_access(self):
paul@0 762
paul@0 763
        "Outside functions, register accesses at the module level."
paul@0 764
paul@0 765
        if not self.in_function:
paul@0 766
            return self.name
paul@0 767
        else:
paul@0 768
            return self.get_namespace_path()
paul@0 769
paul@0 770
    def get_module_name(self, node):
paul@0 771
paul@0 772
        """
paul@0 773
        Using the given From 'node' in this module, calculate any relative import
paul@0 774
        information, returning a tuple containing a module to import along with any
paul@0 775
        names to import based on the node's name information.
paul@0 776
paul@0 777
        Where the returned module is given as None, whole module imports should
paul@0 778
        be performed for the returned modules using the returned names.
paul@0 779
        """
paul@0 780
paul@0 781
        # Absolute import.
paul@0 782
paul@0 783
        if node.level == 0:
paul@0 784
            return node.modname, node.names
paul@0 785
paul@0 786
        # Relative to an ancestor of this module.
paul@0 787
paul@0 788
        else:
paul@0 789
            path = self.name.split(".")
paul@0 790
            level = node.level
paul@0 791
paul@0 792
            # Relative imports treat package roots as submodules.
paul@0 793
paul@0 794
            if split(self.filename)[-1] == "__init__.py":
paul@0 795
                level -= 1
paul@0 796
paul@0 797
            if level > len(path):
paul@0 798
                raise InspectError("Relative import %r involves too many levels up from module %r" % (
paul@0 799
                    ("%s%s" % ("." * node.level, node.modname or "")), self.name))
paul@0 800
paul@0 801
            basename = ".".join(path[:len(path)-level])
paul@0 802
paul@0 803
        # Name imports from a module.
paul@0 804
paul@0 805
        if node.modname:
paul@0 806
            return "%s.%s" % (basename, node.modname), node.names
paul@0 807
paul@0 808
        # Relative whole module imports.
paul@0 809
paul@0 810
        else:
paul@0 811
            return basename, node.names
paul@0 812
paul@0 813
def get_argnames(args):
paul@0 814
paul@0 815
    """
paul@0 816
    Return a list of all names provided by 'args'. Since tuples may be
paul@0 817
    employed, the arguments are traversed depth-first.
paul@0 818
    """
paul@0 819
paul@0 820
    l = []
paul@0 821
    for arg in args:
paul@0 822
        if isinstance(arg, tuple):
paul@0 823
            l += get_argnames(arg)
paul@0 824
        else:
paul@0 825
            l.append(arg)
paul@0 826
    return l
paul@0 827
paul@509 828
def get_names_from_nodes(nodes):
paul@509 829
paul@509 830
    """
paul@509 831
    Return the names employed in the given 'nodes' along with the number of
paul@509 832
    nodes excluding sequences.
paul@509 833
    """
paul@509 834
paul@509 835
    names = set()
paul@509 836
    count = 0
paul@509 837
paul@509 838
    for node in nodes:
paul@509 839
paul@509 840
        # Add names and count them.
paul@509 841
paul@509 842
        if isinstance(node, (compiler.ast.AssName, compiler.ast.Name)):
paul@509 843
            names.add(node.name)
paul@509 844
            count += 1
paul@509 845
paul@509 846
        # Add names from sequences and incorporate their counts.
paul@509 847
paul@509 848
        elif isinstance(node, (compiler.ast.AssList, compiler.ast.AssTuple,
paul@509 849
                               compiler.ast.List, compiler.ast.Set,
paul@509 850
                               compiler.ast.Tuple)):
paul@509 851
            _names, _count = get_names_from_nodes(node.nodes)
paul@509 852
            names.update(_names)
paul@509 853
            count += _count
paul@509 854
paul@509 855
        # Count non-name, non-sequence nodes.
paul@509 856
paul@509 857
        else:
paul@509 858
            count += 1
paul@509 859
paul@509 860
    return names, count
paul@509 861
paul@491 862
# Result classes.
paul@491 863
paul@491 864
class InstructionSequence:
paul@491 865
paul@491 866
    "A generic sequence of instructions."
paul@491 867
paul@491 868
    def __init__(self, instructions):
paul@491 869
        self.instructions = instructions
paul@491 870
paul@491 871
    def get_value_instruction(self):
paul@491 872
        return self.instructions[-1]
paul@491 873
paul@491 874
    def get_init_instructions(self):
paul@491 875
        return self.instructions[:-1]
paul@491 876
paul@0 877
# Dictionary utilities.
paul@0 878
paul@0 879
def init_item(d, key, fn):
paul@0 880
paul@0 881
    """
paul@0 882
    Add to 'd' an entry for 'key' using the callable 'fn' to make an initial
paul@0 883
    value where no entry already exists.
paul@0 884
    """
paul@0 885
paul@0 886
    if not d.has_key(key):
paul@0 887
        d[key] = fn()
paul@0 888
    return d[key]
paul@0 889
paul@0 890
def dict_for_keys(d, keys):
paul@0 891
paul@0 892
    "Return a new dictionary containing entries from 'd' for the given 'keys'."
paul@0 893
paul@0 894
    nd = {}
paul@0 895
    for key in keys:
paul@0 896
        if d.has_key(key):
paul@0 897
            nd[key] = d[key]
paul@0 898
    return nd
paul@0 899
paul@0 900
def make_key(s):
paul@0 901
paul@0 902
    "Make sequence 's' into a tuple-based key, first sorting its contents."
paul@0 903
paul@0 904
    l = list(s)
paul@0 905
    l.sort()
paul@0 906
    return tuple(l)
paul@0 907
paul@0 908
def add_counter_item(d, key):
paul@0 909
paul@0 910
    """
paul@0 911
    Make a mapping in 'd' for 'key' to the number of keys added before it, thus
paul@0 912
    maintaining a mapping of keys to their order of insertion.
paul@0 913
    """
paul@0 914
paul@0 915
    if not d.has_key(key):
paul@0 916
        d[key] = len(d.keys())
paul@0 917
    return d[key] 
paul@0 918
paul@0 919
def remove_items(d1, d2):
paul@0 920
paul@0 921
    "Remove from 'd1' all items from 'd2'."
paul@0 922
paul@0 923
    for key in d2.keys():
paul@0 924
        if d1.has_key(key):
paul@0 925
            del d1[key]
paul@0 926
paul@0 927
# Set utilities.
paul@0 928
paul@0 929
def first(s):
paul@0 930
    return list(s)[0]
paul@0 931
paul@0 932
def same(s1, s2):
paul@0 933
    return set(s1) == set(s2)
paul@0 934
paul@0 935
# General input/output.
paul@0 936
paul@0 937
def readfile(filename):
paul@0 938
paul@0 939
    "Return the contents of 'filename'."
paul@0 940
paul@0 941
    f = open(filename)
paul@0 942
    try:
paul@0 943
        return f.read()
paul@0 944
    finally:
paul@0 945
        f.close()
paul@0 946
paul@0 947
def writefile(filename, s):
paul@0 948
paul@0 949
    "Write to 'filename' the string 's'."
paul@0 950
paul@0 951
    f = open(filename, "w")
paul@0 952
    try:
paul@0 953
        f.write(s)
paul@0 954
    finally:
paul@0 955
        f.close()
paul@0 956
paul@0 957
# General encoding.
paul@0 958
paul@0 959
def sorted_output(x):
paul@0 960
paul@0 961
    "Sort sequence 'x' and return a string with commas separating the values."
paul@0 962
paul@0 963
    x = map(str, x)
paul@0 964
    x.sort()
paul@0 965
    return ", ".join(x)
paul@0 966
paul@537 967
def get_string_details(literals, encoding):
paul@512 968
paul@512 969
    """
paul@537 970
    Determine whether 'literals' represent Unicode strings or byte strings,
paul@537 971
    using 'encoding' to reproduce byte sequences.
paul@537 972
paul@537 973
    Each literal is the full program representation including prefix and quotes
paul@537 974
    recoded by the parser to UTF-8. Thus, any literal found to represent a byte
paul@537 975
    string needs to be translated back to its original encoding.
paul@537 976
paul@537 977
    Return a single encoded literal value, a type name, and the original
paul@537 978
    encoding as a tuple.
paul@537 979
    """
paul@537 980
paul@537 981
    typename = "unicode"
paul@537 982
paul@537 983
    l = []
paul@537 984
paul@537 985
    for s in literals:
paul@537 986
        out, _typename = get_literal_details(s)
paul@537 987
        if _typename == "str":
paul@537 988
            typename = "str"
paul@537 989
        l.append(out)
paul@537 990
paul@537 991
    out = "".join(l)
paul@537 992
paul@537 993
    # For Unicode values, convert to the UTF-8 program representation.
paul@537 994
paul@537 995
    if typename == "unicode":
paul@537 996
        return out.encode("utf-8"), typename, encoding
paul@537 997
paul@537 998
    # For byte string values, convert back to the original encoding.
paul@537 999
paul@537 1000
    else:
paul@537 1001
        return out.encode(encoding), typename, encoding
paul@537 1002
paul@537 1003
def get_literal_details(s):
paul@537 1004
paul@537 1005
    """
paul@537 1006
    Determine whether 's' represents a Unicode string or a byte string, where
paul@537 1007
    's' contains the full program representation of a literal including prefix
paul@537 1008
    and quotes, recoded by the parser to UTF-8.
paul@512 1009
paul@512 1010
    Find and convert Unicode values starting with <backslash>u or <backslash>U,
paul@512 1011
    and byte or Unicode values starting with <backslash><octal digit> or
paul@512 1012
    <backslash>x.
paul@512 1013
paul@512 1014
    Literals prefixed with "u" cause <backslash><octal digit> and <backslash>x
paul@512 1015
    to be considered as Unicode values. Otherwise, they produce byte values and
paul@512 1016
    cause unprefixed strings to be considered as byte strings.
paul@512 1017
paul@512 1018
    Literals prefixed with "r" do not have their backslash-encoded values
paul@512 1019
    converted unless also prefixed with "u", in which case only the above value
paul@512 1020
    formats are converted, not any of the other special sequences for things
paul@512 1021
    like newlines.
paul@512 1022
paul@537 1023
    Return the literal value as a Unicode object together with the appropriate
paul@537 1024
    type name in a tuple.
paul@512 1025
    """
paul@512 1026
paul@512 1027
    l = []
paul@512 1028
paul@512 1029
    # Identify the quote character and use it to identify the prefix.
paul@512 1030
paul@512 1031
    quote_type = s[-1]
paul@512 1032
    prefix_end = s.find(quote_type)
paul@512 1033
    prefix = s[:prefix_end].lower()
paul@512 1034
paul@512 1035
    if prefix not in ("", "b", "br", "r", "u", "ur"):
paul@512 1036
        raise ValueError, "String literal does not have a supported prefix: %s" % s
paul@512 1037
paul@513 1038
    if "b" in prefix:
paul@513 1039
        typename = "str"
paul@513 1040
    else:
paul@513 1041
        typename = "unicode"
paul@513 1042
paul@512 1043
    # Identify triple quotes or single quotes.
paul@512 1044
paul@512 1045
    if len(s) >= 6 and s[-2] == quote_type and s[-3] == quote_type:
paul@512 1046
        quote = s[prefix_end:prefix_end+3]
paul@512 1047
        current = prefix_end + 3
paul@512 1048
        end = len(s) - 3
paul@512 1049
    else:
paul@512 1050
        quote = s[prefix_end]
paul@512 1051
        current = prefix_end + 1
paul@512 1052
        end = len(s) - 1
paul@512 1053
paul@512 1054
    # Conversions of some quoted values.
paul@512 1055
paul@512 1056
    searches = {
paul@512 1057
        "u" : (6, 16),
paul@512 1058
        "U" : (10, 16),
paul@512 1059
        "x" : (4, 16),
paul@512 1060
        }
paul@512 1061
paul@512 1062
    octal_digits = map(str, range(0, 8))
paul@512 1063
paul@512 1064
    # Translations of some quoted values.
paul@512 1065
paul@512 1066
    escaped = {
paul@512 1067
        "\\" : "\\", "'" : "'", '"' : '"',
paul@512 1068
        "a" : "\a", "b" : "\b", "f" : "\f",
paul@512 1069
        "n" : "\n", "r" : "\r", "t" : "\t",
paul@512 1070
        }
paul@512 1071
paul@512 1072
    while current < end:
paul@512 1073
paul@512 1074
        # Look for quoted values.
paul@512 1075
paul@512 1076
        index = s.find("\\", current)
paul@512 1077
        if index == -1 or index + 1 == end:
paul@512 1078
            l.append(s[current:end])
paul@512 1079
            break
paul@512 1080
paul@512 1081
        # Add the preceding text.
paul@512 1082
paul@512 1083
        l.append(s[current:index])
paul@512 1084
paul@512 1085
        # Handle quoted text.
paul@512 1086
paul@512 1087
        term = s[index+1]
paul@512 1088
paul@512 1089
        # Add Unicode values. Where a string is u-prefixed, even \o and \x
paul@512 1090
        # produce Unicode values.
paul@512 1091
paul@513 1092
        if typename == "unicode" and (
paul@513 1093
            term in ("u", "U") or 
paul@513 1094
            "u" in prefix and (term == "x" or term in octal_digits)):
paul@512 1095
paul@512 1096
            needed, base = searches.get(term, (4, 8))
paul@512 1097
            value = convert_quoted_value(s, index, needed, end, base, unichr)
paul@512 1098
            l.append(value)
paul@512 1099
            current = index + needed
paul@512 1100
paul@512 1101
        # Add raw byte values, changing the string type.
paul@512 1102
paul@512 1103
        elif "r" not in prefix and (
paul@512 1104
             term == "x" or term in octal_digits):
paul@512 1105
paul@512 1106
            needed, base = searches.get(term, (4, 8))
paul@512 1107
            value = convert_quoted_value(s, index, needed, end, base, chr)
paul@512 1108
            l.append(value)
paul@512 1109
            typename = "str"
paul@512 1110
            current = index + needed
paul@512 1111
paul@512 1112
        # Add other escaped values.
paul@512 1113
paul@512 1114
        elif "r" not in prefix and escaped.has_key(term):
paul@512 1115
            l.append(escaped[term])
paul@512 1116
            current = index + 2
paul@512 1117
paul@512 1118
        # Add other text as found.
paul@512 1119
paul@512 1120
        else:
paul@512 1121
            l.append(s[index:index+2])
paul@512 1122
            current = index + 2
paul@512 1123
paul@537 1124
    # Collect the components into a single Unicode object. Since the literal
paul@537 1125
    # text was already in UTF-8 form, interpret plain strings as UTF-8
paul@537 1126
    # sequences.
paul@512 1127
paul@537 1128
    out = []
paul@512 1129
paul@537 1130
    for value in l:
paul@537 1131
        if isinstance(value, unicode):
paul@537 1132
            out.append(value)
paul@537 1133
        else:
paul@537 1134
            out.append(unicode(value, "utf-8"))
paul@512 1135
paul@537 1136
    return "".join(out), typename
paul@512 1137
paul@512 1138
def convert_quoted_value(s, index, needed, end, base, fn):
paul@512 1139
paul@512 1140
    """
paul@512 1141
    Interpret a quoted value in 's' at 'index' with the given 'needed' number of
paul@512 1142
    positions, and with the given 'end' indicating the first position after the
paul@512 1143
    end of the actual string content.
paul@512 1144
paul@512 1145
    Use 'base' as the numerical base when interpreting the value, and use 'fn'
paul@512 1146
    to convert the value to an appropriate type.
paul@512 1147
    """
paul@512 1148
paul@512 1149
    s = s[index:min(index+needed, end)]
paul@512 1150
paul@512 1151
    # Not a complete occurrence.
paul@512 1152
paul@512 1153
    if len(s) < needed:
paul@512 1154
        return s
paul@512 1155
paul@512 1156
    # Test for a well-formed value.
paul@512 1157
paul@512 1158
    try:
paul@512 1159
        first = base == 8 and 1 or 2
paul@512 1160
        value = int(s[first:needed], base)
paul@512 1161
    except ValueError:
paul@512 1162
        return s
paul@512 1163
    else:
paul@512 1164
        return fn(value)
paul@512 1165
paul@0 1166
# Attribute chain decoding.
paul@0 1167
paul@0 1168
def get_attrnames(attrnames):
paul@11 1169
paul@11 1170
    """
paul@11 1171
    Split the qualified attribute chain 'attrnames' into its components,
paul@11 1172
    handling special attributes starting with "#" that indicate type
paul@11 1173
    conformance.
paul@11 1174
    """
paul@11 1175
paul@0 1176
    if attrnames.startswith("#"):
paul@0 1177
        return [attrnames]
paul@0 1178
    else:
paul@0 1179
        return attrnames.split(".")
paul@0 1180
paul@0 1181
def get_attrname_from_location(location):
paul@11 1182
paul@11 1183
    """
paul@11 1184
    Extract the first attribute from the attribute names employed in a
paul@11 1185
    'location'.
paul@11 1186
    """
paul@11 1187
paul@0 1188
    path, name, attrnames, access = location
paul@91 1189
    if not attrnames:
paul@91 1190
        return attrnames
paul@0 1191
    return get_attrnames(attrnames)[0]
paul@0 1192
paul@85 1193
def get_name_path(path, name):
paul@85 1194
paul@85 1195
    "Return a suitable qualified name from the given 'path' and 'name'."
paul@85 1196
paul@85 1197
    if "." in name:
paul@85 1198
        return name
paul@85 1199
    else:
paul@85 1200
        return "%s.%s" % (path, name)
paul@85 1201
paul@90 1202
# Usage-related functions.
paul@89 1203
paul@89 1204
def get_types_for_usage(attrnames, objects):
paul@89 1205
paul@89 1206
    """
paul@89 1207
    Identify the types that can support the given 'attrnames', using the
paul@89 1208
    given 'objects' as the catalogue of type details.
paul@89 1209
    """
paul@89 1210
paul@89 1211
    types = []
paul@89 1212
    for name, _attrnames in objects.items():
paul@89 1213
        if set(attrnames).issubset(_attrnames):
paul@89 1214
            types.append(name)
paul@89 1215
    return types
paul@89 1216
paul@90 1217
def get_invoked_attributes(usage):
paul@90 1218
paul@90 1219
    "Obtain invoked attribute from the given 'usage'."
paul@90 1220
paul@90 1221
    invoked = []
paul@90 1222
    if usage:
paul@107 1223
        for attrname, invocation, assignment in usage:
paul@90 1224
            if invocation:
paul@90 1225
                invoked.append(attrname)
paul@90 1226
    return invoked
paul@90 1227
paul@107 1228
def get_assigned_attributes(usage):
paul@107 1229
paul@107 1230
    "Obtain assigned attribute from the given 'usage'."
paul@107 1231
paul@107 1232
    assigned = []
paul@107 1233
    if usage:
paul@107 1234
        for attrname, invocation, assignment in usage:
paul@107 1235
            if assignment:
paul@107 1236
                assigned.append(attrname)
paul@107 1237
    return assigned
paul@107 1238
paul@366 1239
# Type and module functions.
paul@538 1240
# NOTE: This makes assumptions about the __builtins__ structure.
paul@366 1241
paul@366 1242
def get_builtin_module(name):
paul@366 1243
paul@366 1244
    "Return the module name containing the given type 'name'."
paul@366 1245
paul@394 1246
    if name == "string":
paul@538 1247
        modname = "str"
paul@394 1248
    elif name == "utf8string":
paul@538 1249
        modname = "unicode"
paul@394 1250
    elif name == "NoneType":
paul@538 1251
        modname = "none"
paul@394 1252
    else:
paul@538 1253
        modname = name
paul@538 1254
paul@538 1255
    return "__builtins__.%s" % modname
paul@366 1256
paul@366 1257
def get_builtin_type(name):
paul@366 1258
paul@366 1259
    "Return the type name provided by the given Python value 'name'."
paul@366 1260
paul@394 1261
    if name == "str":
paul@394 1262
        return "string"
paul@394 1263
    elif name == "unicode":
paul@394 1264
        return "utf8string"
paul@394 1265
    else:
paul@394 1266
        return name
paul@366 1267
paul@538 1268
def get_builtin_class(name):
paul@538 1269
paul@538 1270
    "Return the full name of the built-in class having the given 'name'."
paul@538 1271
paul@538 1272
    typename = get_builtin_type(name)
paul@538 1273
    module = get_builtin_module(typename)
paul@538 1274
    return "%s.%s" % (module, typename)
paul@538 1275
paul@0 1276
# Useful data.
paul@0 1277
paul@11 1278
predefined_constants = "False", "None", "NotImplemented", "True"
paul@0 1279
paul@0 1280
operator_functions = {
paul@0 1281
paul@0 1282
    # Fundamental operations.
paul@0 1283
paul@0 1284
    "is" : "is_",
paul@0 1285
    "is not" : "is_not",
paul@0 1286
paul@0 1287
    # Binary operations.
paul@0 1288
paul@0 1289
    "in" : "in_",
paul@0 1290
    "not in" : "not_in",
paul@0 1291
    "Add" : "add",
paul@0 1292
    "Bitand" : "and_",
paul@0 1293
    "Bitor" : "or_",
paul@0 1294
    "Bitxor" : "xor",
paul@0 1295
    "Div" : "div",
paul@0 1296
    "FloorDiv" : "floordiv",
paul@0 1297
    "LeftShift" : "lshift",
paul@0 1298
    "Mod" : "mod",
paul@0 1299
    "Mul" : "mul",
paul@0 1300
    "Power" : "pow",
paul@0 1301
    "RightShift" : "rshift",
paul@0 1302
    "Sub" : "sub",
paul@0 1303
paul@0 1304
    # Unary operations.
paul@0 1305
paul@0 1306
    "Invert" : "invert",
paul@0 1307
    "UnaryAdd" : "pos",
paul@0 1308
    "UnarySub" : "neg",
paul@0 1309
paul@0 1310
    # Augmented assignment.
paul@0 1311
paul@0 1312
    "+=" : "iadd",
paul@0 1313
    "-=" : "isub",
paul@0 1314
    "*=" : "imul",
paul@0 1315
    "/=" : "idiv",
paul@0 1316
    "//=" : "ifloordiv",
paul@0 1317
    "%=" : "imod",
paul@0 1318
    "**=" : "ipow",
paul@0 1319
    "<<=" : "ilshift",
paul@0 1320
    ">>=" : "irshift",
paul@0 1321
    "&=" : "iand",
paul@0 1322
    "^=" : "ixor",
paul@0 1323
    "|=" : "ior",
paul@0 1324
paul@0 1325
    # Comparisons.
paul@0 1326
paul@0 1327
    "==" : "eq",
paul@0 1328
    "!=" : "ne",
paul@0 1329
    "<" : "lt",
paul@0 1330
    "<=" : "le",
paul@0 1331
    ">=" : "ge",
paul@0 1332
    ">" : "gt",
paul@0 1333
    }
paul@0 1334
paul@0 1335
# vim: tabstop=4 expandtab shiftwidth=4