Experimental parser: rule grammar refactor

tools/lexer_generator/rule_lexer.py

 # Copyright 2013 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
@@ skipping 12 matching lines @@
 # 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.
 
 import ply.lex as lex
 
 class RuleLexer:
 
   tokens = (
-    'DEFAULT',
     'DEFAULT_ACTION',
     'CATCH_ALL',
-    'PUSH_TOKEN',
 
     'IDENTIFIER',
     'STRING',
     'REGEX',
     'CHARACTER_CLASS_REGEX',
 
     'PLUS',
     'QUESTION_MARK',
     'EQUALS',
     'OR',
     'STAR',
     'LEFT_PARENTHESIS',
     'RIGHT_PARENTHESIS',
-    'LESS_THAN',
-    'GREATER_THAN',
+    'GRAPH_OPEN',
+    'GRAPH_CLOSE',
     'SEMICOLON',
     'ACTION_OPEN',
     'ACTION_CLOSE',
 
     'LEFT_BRACKET',
     'RIGHT_BRACKET',
 
     'CODE_FRAGMENT',
   )
 
   states = (
     ('code','exclusive'),
   )
 
   t_ignore = " \t\n\r"
   t_code_ignore = ""
 
   def t_COMMENT(self, t):
     r'\#.*[\n\r]+'
     pass
 
   __special_identifiers = set(map(lambda s: s.lower(),
-    ['DEFAULT', 'DEFAULT_ACTION', 'CATCH_ALL', 'PUSH_TOKEN']))
+    ['DEFAULT_ACTION', 'CATCH_ALL']))
 
   def t_IDENTIFIER(self, t):
     r'[a-zA-Z][a-zA-Z0-9_]*'
     if t.value in self.__special_identifiers:
       t.type = t.value.upper()
     return t
 
   t_STRING = r'"((\\("|\w|\\))|[^\\"])+"'
   t_REGEX = r'/(\\/|[^/])+/'
   t_CHARACTER_CLASS_REGEX = r'\[([^\]]|\\\])+\]'
 
   t_PLUS = r'\+'
   t_QUESTION_MARK = r'\?'
   t_STAR = r'\*'
   t_OR = r'\|'
   t_EQUALS = '='
   t_LEFT_PARENTHESIS = r'\('
   t_RIGHT_PARENTHESIS = r'\)'
-  t_LESS_THAN = '<'
-  t_GREATER_THAN = '>'
+  t_GRAPH_OPEN = '<<'
+  t_GRAPH_CLOSE = '>>'
   t_SEMICOLON = ';'
-  t_ACTION_OPEN = '<<'
-  t_ACTION_CLOSE = '>>'
+  t_ACTION_OPEN = '<'
+  t_ACTION_CLOSE = '>'
 
   def t_LEFT_BRACKET(self, t):
     r'{'
     self.lexer.push_state('code')
     self.nesting = 1
     return t
 
   t_code_CODE_FRAGMENT = r'[^{}]+'
 
   def t_code_LEFT_BRACKET(self, t):
     r'{'
     self.nesting += 1
     t.type = 'CODE_FRAGMENT'
     return t
 
   def t_code_RIGHT_BRACKET(self, t):
     r'}'
     self.nesting -= 1
     if self.nesting:
       t.type = 'CODE_FRAGMENT'
     else:
       self.lexer.pop_state()
     return t
 
   def t_ANY_error(self, t):
     raise Exception("Illegal character '%s'" % t.value[0])
 
   def build(self, **kwargs):
     self.lexer = lex.lex(module=self, **kwargs)