anchor.diff:  fragment
   F_IpPrefixLength
   :
  -  F_Digit
  -  | [12] F_Digit
  -  | [3] [012]
  +    F_Digit
  +    | [12] F_Digit
  +    | [3] [012]
   ;
   
   fragment
  
positive.code:     F_Newline+
  ;
  
  RANGE
  :
      F_Digit+ '-' F_Digit+
  
negative.code: SINGLE_QUOTED_STRING
  :
      '\'' ~'\''* '\''
  ;
  
  UINT8
  :
      F_Uint8
  ;
  
  UINT16
  :
      F_Uint16
  ;
  
  UINT32
  :
      F_Uint32
  ;
  
  VARIABLE
  