anchor.diff:  
   CLASS
       :   'class'
  +    ;
  +
  +CONTINUE
  +    :   'continue'
       ;
   
   DO
  
positive.code:     : 'break' expression?
      -> ^(BREAK_STMT expression?)
      ;
      
  retryDirective
      : 'retry'
      -> ^(RETRY_STMT)
  
negative.code:         |   'n' 
          |   'f' 
          |   'r'
          //|   's' 
          |   '\"' 
          |   '\''
          )          
  