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