Experimental parser: split and rename some files

tools/lexer_generator/action.py

-# Copyright 2014 the V8 project authors. All rights reserved.
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-#       notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-#       copyright notice, this list of conditions and the following
-#       disclaimer in the documentation and/or other materials provided
-#       with the distribution.
-#     * Neither the name of Google Inc. nor the names of its
-#       contributors may be used to endorse or promote products derived
-#       from this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-from types import StringType, IntType
-
-class Term(object):
-  '''An immutable class representing a function and its arguments.
-  f(a,b,c) would be represented as ('f', a, b, c) where
-  a, b, and c are strings, integers or Terms.'''
-
-  __empty_term = None
-
-  @staticmethod
-  def empty_term():
-    if Term.__empty_term == None:
-      Term.__empty_term = Term('')
-    return Term.__empty_term
-
-  def __init__(self, name, *args):
-    assert type(name) == StringType
-    assert name or not args, 'empty term must not have args'
-    for v in args:
-      assert type(v) == IntType or type(v) == StringType or isinstance(v, Term)
-    self.__tuple = tuple([name] + list(args))
-    self.__str = None
-
-  def name(self):
-    return self.__tuple[0]
-
-  def args(self):
-    return self.__tuple[1:]
-
-  def  __hash__(self):
-    return hash(self.__tuple)
-
-  def __nonzero__(self):
-    'true <==> self == empty_term'
-    return bool(self.__tuple[0])
-
-  def __eq__(self, other):
-    return (isinstance(other, self.__class__) and self.__tuple == other.__tuple)
-
-  # TODO(dcarney): escape '(', ')' and ',' in strings
-  def __str__(self):
-    if self.__str == None:
-      self.__str = '(%s)' % ','.join(map(str, self.__tuple))
-    return self.__str
-
-class Action(object):
-
-  __empty_action = None
-
-  @staticmethod
-  def empty_action():
-    if Action.__empty_action == None:
-      Action.__empty_action = Action(Term.empty_term(), -1)
-    return Action.__empty_action
-
-  @staticmethod
-  def dominant_action(actions):
-    dominant = Action.empty_action()
-    for action in actions:
-      if not action:
-        continue
-      if not dominant:
-        dominant = action
-        continue
-      if action.precedence() == dominant.precedence():
-        assert action.__term == dominant.__term
-      elif action.precedence() < dominant.precedence():
-        dominant = action
-    return dominant
-
-  def __init__(self, term, precedence):
-    assert isinstance(term, Term)
-    assert type(precedence) == IntType
-    assert not term or precedence >= 0, 'action must have positive precedence'
-    self.__term = term
-    self.__precedence = precedence
-
-  def name(self):
-    return self.__term.name()
-
-  def term(self):
-    return self.__term
-
-  def precedence(self):
-    return self.__precedence
-
-  def __nonzero__(self):
-    'true <==> self == empty_action'
-    return bool(self.__term)
-
-  def __eq__(self, other):
-    return isinstance(other, self.__class__) and self.__term == other.__term
-
-  def __str__(self):
-    return "action <%s>" % ('' if not self.__term else str(self.__term))