# 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")

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.iteritems():

            setattr(self, name, symbol)

python_grammar = driver.load_grammar(_GRAMMAR_FILE)

python_symbols = Symbols(python_grammar)

def parenthesize(node):

    return pytree.Node(python_symbols.atom,

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

                        node,

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