anchor.diff:  
   
   //-----------------------------------------------------------------
  -
   // SPX Protocol rules.
  -
   // (PROTOCOL = SPX)(SERVICE = spx_service_name)
  -
  -//-----------------------------------------------------------------
  -spx_protocol     : spx_params ; 
  -
  -spx_params       : spx_parameter+ ; 
  +//-----------------------------------------------------------------
  +spx_protocol     : spx_params ;
  +
  +spx_params       : spx_parameter+ ;
   
   spx_parameter    : spx_spx
  -                 | spx_service ; 
  -
  -spx_spx          : L_PAREN PROTOCOL EQUAL SPX R_PAREN ; 
  +                 | spx_service ;
  +
  +spx_spx          : L_PAREN PROTOCOL EQUAL SPX R_PAREN ;
   
   spx_service      : L_PAREN SERVICE EQUAL ID R_PAREN ;
   
  
positive.code: //-----------------------------------------------------------------
  // TCP Protocol rules.
  // (PROTOCOL = TCP)(HOST = hostname)(PORT = portnumber)
  
  //-----------------------------------------------------------------
  tcp_protocol     : tcp_params ;
                   
  
negative.code: 
  fragment
  DIGIT            : [0-9] ;
  
  fragment
  OCT_DIGIT        : [0-8] ;
  
  fragment
  HEX_DIGIT        : [0-9A-Fa-f] ;
                   
  fragment
  LIST             : L I S T ;
  