anchor.diff:      : '"' .*? '"'
       ;
   
  -fragment LETTER
  +fragment UPPERCASE_LETTER
  +    : 'A'..'Z'
  +    ;
  +
  +fragment LOWERCASE_LETTER
       : 'a'..'z'
  -    | 'A'..'Z'
       ;
   
   fragment DIGIT
  
positive.code:     | zeroormore
      | oneormore
      | text
      | id
      ;
  
  
negative.code: 
  oneormore
      : RPAREN alternatives LPAREN
      ;
  
  captext
      : CAPTEXT
      ;
  
  text
  