Experimental parser: small cleanup

tools/lexer_generator/nfa_builder.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 291 matching lines @@
   }
 
   @staticmethod
   def apply_modifier(modifier, term):
     return Term(NfaBuilder.__modifer_map[modifier], term)
 
   @staticmethod
   def __flatten_terms(terms, name):
     for term in terms:
       assert isinstance(term, Term)
-      if not term:
-        continue
       if term.name() == name:
         for arg in term.args():
           if arg:
             yield arg
       else:
-        yield term
+        if term:
+          yield term
 
   @staticmethod
   def __flatten_literals(terms):
     acc = ()
     for term in terms:
       assert isinstance(term, Term)
-      if not term:
-        continue
       if term.name() == 'LITERAL':
         acc += term.args()
       else:
         if acc:
           yield Term('LITERAL', *acc)
           acc = ()
         if term:
           yield term
     if acc:
       yield Term('LITERAL', *acc)
 
   @staticmethod
   def or_terms(terms):
     terms = list(NfaBuilder.__flatten_terms(terms, 'OR'))
     assert terms
     return terms[0] if len(terms) == 1 else Term('OR', *terms)
 
   @staticmethod
   def cat_terms(terms):
     terms = NfaBuilder.__flatten_terms(terms, 'CAT')
     terms = list(NfaBuilder.__flatten_literals(terms))
     assert terms
     return terms[0] if len(terms) == 1 else Term('CAT', *terms)