anchor.diff:     ;
   
   
  -
   OPTIONS
      : 'options' WS_LOOP '{'
      ;
  
positive.code:    : '/*' .*? '*/' -> skip
     ;
  
  WS
     : (' ' | '\t' | '\r'? '\n') + -> skip
     ;
  
  TOKEN_REF
     : 'A' .. 'Z' ('a' .. 'z' | 'A' .. 'Z' | '_' | '0' .. '9')*
     ;
  
  RULE_REF
     : 'a' .. 'z' ('a' .. 'z' | 'A' .. 'Z' | '_' | '0' .. '9')*
     ;
  
negative.code: grammar ANTLRv3;
  
  grammarDef
     : DOC_COMMENT? ('lexer' | 'parser' | 'tree')? 'grammar' id ';' optionsSpec? tokensSpec? attrScope* action* rule_ +
     ;
  
  tokensSpec
  