#!/usr/bin/env python

#

# Copyright 2007 Google Inc.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#     http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

#

"""A wrapper around the generated Groc parser and lexer."""

import google

import antlr3

import GrocLexer

import GrocParser

class GrocException(Exception):

  """An error occurred while parsing the groc input string."""

class GrocLexerWithErrors(GrocLexer.GrocLexer):

  """An overridden Lexer that raises exceptions."""

  def emitErrorMessage(self, msg):

    """Raise an exception if the input fails to parse correctly.

    Overriding the default, which normally just prints a message to

    stderr.

    Arguments:

      msg: the error message

    Raises:

      GrocException: always.

    """

    raise GrocException(msg)

class GrocParserWithErrors(GrocParser.GrocParser):

  """An overridden Parser that raises exceptions."""

  def emitErrorMessage(self, msg):

    """Raise an exception if the input fails to parse correctly.

    Overriding the default, which normally just prints a message to

    stderr.

    Arguments:

      msg: the error message

    Raises:

      GrocException: always.

    """

    raise GrocException(msg)

def CreateParser(parse_string):

  """Creates a Groc Parser."""

  input_string = antlr3.ANTLRStringStream(parse_string)

  lexer = GrocLexerWithErrors(input_string)

  tokens = antlr3.CommonTokenStream(lexer)

  parser = GrocParserWithErrors(tokens)

  return parser