Import lib2to3.
diff --git a/Lib/lib2to3/pgen2/grammar.py b/Lib/lib2to3/pgen2/grammar.py
new file mode 100644
index 0000000..7818c24
--- /dev/null
+++ b/Lib/lib2to3/pgen2/grammar.py
@@ -0,0 +1,171 @@
+# Copyright 2004-2005 Elemental Security, Inc. All Rights Reserved.
+# Licensed to PSF under a Contributor Agreement.
+
+"""This module defines the data structures used to represent a grammar.
+
+These are a bit arcane because they are derived from the data
+structures used by Python's 'pgen' parser generator.
+
+There's also a table here mapping operators to their names in the
+token module; the Python tokenize module reports all operators as the
+fallback token code OP, but the parser needs the actual token code.
+
+"""
+
+# Python imports
+import pickle
+
+# Local imports
+from . import token, tokenize
+
+
+class Grammar(object):
+ """Pgen parsing tables tables conversion class.
+
+ Once initialized, this class supplies the grammar tables for the
+ parsing engine implemented by parse.py. The parsing engine
+ accesses the instance variables directly. The class here does not
+ provide initialization of the tables; several subclasses exist to
+ do this (see the conv and pgen modules).
+
+ The load() method reads the tables from a pickle file, which is
+ much faster than the other ways offered by subclasses. The pickle
+ file is written by calling dump() (after loading the grammar
+ tables using a subclass). The report() method prints a readable
+ representation of the tables to stdout, for debugging.
+
+ The instance variables are as follows:
+
+ symbol2number -- a dict mapping symbol names to numbers. Symbol
+ numbers are always 256 or higher, to distinguish
+ them from token numbers, which are between 0 and
+ 255 (inclusive).
+
+ number2symbol -- a dict mapping numbers to symbol names;
+ these two are each other's inverse.
+
+ states -- a list of DFAs, where each DFA is a list of
+ states, each state is is a list of arcs, and each
+ arc is a (i, j) pair where i is a label and j is
+ a state number. The DFA number is the index into
+ this list. (This name is slightly confusing.)
+ Final states are represented by a special arc of
+ the form (0, j) where j is its own state number.
+
+ dfas -- a dict mapping symbol numbers to (DFA, first)
+ pairs, where DFA is an item from the states list
+ above, and first is a set of tokens that can
+ begin this grammar rule (represented by a dict
+ whose values are always 1).
+
+ labels -- a list of (x, y) pairs where x is either a token
+ number or a symbol number, and y is either None
+ or a string; the strings are keywords. The label
+ number is the index in this list; label numbers
+ are used to mark state transitions (arcs) in the
+ DFAs.
+
+ start -- the number of the grammar's start symbol.
+
+ keywords -- a dict mapping keyword strings to arc labels.
+
+ tokens -- a dict mapping token numbers to arc labels.
+
+ """
+
+ def __init__(self):
+ self.symbol2number = {}
+ self.number2symbol = {}
+ self.states = []
+ self.dfas = {}
+ self.labels = [(0, "EMPTY")]
+ self.keywords = {}
+ self.tokens = {}
+ self.symbol2label = {}
+ self.start = 256
+
+ def dump(self, filename):
+ """Dump the grammar tables to a pickle file."""
+ f = open(filename, "wb")
+ pickle.dump(self.__dict__, f, 2)
+ f.close()
+
+ def load(self, filename):
+ """Load the grammar tables from a pickle file."""
+ f = open(filename, "rb")
+ d = pickle.load(f)
+ f.close()
+ self.__dict__.update(d)
+
+ def report(self):
+ """Dump the grammar tables to standard output, for debugging."""
+ from pprint import pprint
+ print "s2n"
+ pprint(self.symbol2number)
+ print "n2s"
+ pprint(self.number2symbol)
+ print "states"
+ pprint(self.states)
+ print "dfas"
+ pprint(self.dfas)
+ print "labels"
+ pprint(self.labels)
+ print "start", self.start
+
+
+# Map from operator to number (since tokenize doesn't do this)
+
+opmap_raw = """
+( LPAR
+) RPAR
+[ LSQB
+] RSQB
+: COLON
+, COMMA
+; SEMI
++ PLUS
+- MINUS
+* STAR
+/ SLASH
+| VBAR
+& AMPER
+< LESS
+> GREATER
+= EQUAL
+. DOT
+% PERCENT
+` BACKQUOTE
+{ LBRACE
+} RBRACE
+@ AT
+== EQEQUAL
+!= NOTEQUAL
+<> NOTEQUAL
+<= LESSEQUAL
+>= GREATEREQUAL
+~ TILDE
+^ CIRCUMFLEX
+<< LEFTSHIFT
+>> RIGHTSHIFT
+** DOUBLESTAR
++= PLUSEQUAL
+-= MINEQUAL
+*= STAREQUAL
+/= SLASHEQUAL
+%= PERCENTEQUAL
+&= AMPEREQUAL
+|= VBAREQUAL
+^= CIRCUMFLEXEQUAL
+<<= LEFTSHIFTEQUAL
+>>= RIGHTSHIFTEQUAL
+**= DOUBLESTAREQUAL
+// DOUBLESLASH
+//= DOUBLESLASHEQUAL
+-> RARROW
+"""
+
+opmap = {}
+for line in opmap_raw.splitlines():
+ if line:
+ op, name = line.split()
+ opmap[op] = getattr(token, name)