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cpython/Lib/lib2to3/pygram.py
Benjamin Peterson 8a5877165e
bpo-24960: use pkgutil.get_data in lib2to3 to read pickled grammar files (#4977)
This is more complicated than it should be because we need to preserve the
useful mtime-based regeneration feature that lib2to3.pgen2.driver.load_grammar
has. We only look for the pickled grammar file with pkgutil.get_data and only if
the source file does not exist.
2017-12-22 12:18:33 -08:00

41 lines
1.1 KiB
Python

# Copyright 2006 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.
"""Export the Python grammar and symbols."""
# Python imports
import os
# Local imports
from .pgen2 import token
from .pgen2 import driver
from . import pytree
# The grammar file
_GRAMMAR_FILE = os.path.join(os.path.dirname(__file__), "Grammar.txt")
_PATTERN_GRAMMAR_FILE = os.path.join(os.path.dirname(__file__),
"PatternGrammar.txt")
class Symbols(object):
def __init__(self, grammar):
"""Initializer.
Creates an attribute for each grammar symbol (nonterminal),
whose value is the symbol's type (an int >= 256).
"""
for name, symbol in grammar.symbol2number.items():
setattr(self, name, symbol)
python_grammar = driver.load_packaged_grammar("lib2to3", _GRAMMAR_FILE)
python_symbols = Symbols(python_grammar)
python_grammar_no_print_statement = python_grammar.copy()
del python_grammar_no_print_statement.keywords["print"]
pattern_grammar = driver.load_packaged_grammar("lib2to3", _PATTERN_GRAMMAR_FILE)
pattern_symbols = Symbols(pattern_grammar)