anchor.diff:      : CSTRING
       ;
   
  +ipValue
  +    : IP
  +    ;
  +
   signedNumber:
       NUMBER
       ;
  
positive.code:     |   stringValue
      |   bitsValue
      |   objectIdentifierValue
      ;
  
  value
  
negative.code: 
  fragment LOWER
      : ('a'..'z')
      ;
  
  IP :
      DIGIT+ '.' DIGIT+  '.' DIGIT+  '.' DIGIT+ 
      ;
  
  NUMBER
  