1 # Copyright 2006 Google, Inc. All Rights Reserved.

     2 # Licensed to PSF under a Contributor Agreement.

     3 

     4 """Export the Python grammar and symbols."""

     5 

     6 # Python imports

     7 import os

     8 

     9 # Local imports

    10 from .pgen2 import token

    11 from .pgen2 import driver

    12 from . import pytree

    13 

    14 # The grammar file

    15 _GRAMMAR_FILE = os.path.join(os.path.dirname(__file__), "Grammar.txt")

    16 

    17 

    18 class Symbols(object):

    19 

    20     def __init__(self, grammar):

    21         """Initializer.

    22 

    23         Creates an attribute for each grammar symbol (nonterminal),

    24         whose value is the symbol's type (an int >= 256).

    25         """

    26         for name, symbol in grammar.symbol2number.iteritems():

    27             setattr(self, name, symbol)

    28 

    29 

    30 python_grammar = driver.load_grammar(_GRAMMAR_FILE)

    31 python_symbols = Symbols(python_grammar)

    32 

    33 

    34 def parenthesize(node):

    35     return pytree.Node(python_symbols.atom,

    36                        (pytree.Leaf(token.LPAR, "("),

    37                         node,

    38                         pytree.Leaf(token.RPAR, ")")))