anchor.diff:  
   dataRedefinesClause :
   	REDEFINES dataName
  +;
  +
  +dataIntegerStringClause :
  +	INTEGER | STRING
   ;
   
   dataBlankWhenZeroClause :
  
positive.code: INPUT_OUTPUT : I N P U T MINUSCHAR O U T P U T;
  INSPECT : I N S P E C T;
  INSTALLATION : I N S T A L L A T I O N;
  INTO : I N T O;
  INVALID : I N V A L I D;
  IS : I S;
  
negative.code: 	(INTEGERLITERAL | LEVEL_NUMBER_77)
  	(dataName | FILLER)?
  	dataRedefinesClause?
  	dataIntegerStringClause?
  	dataExternalClause?
  	dataGlobalClause?
  	dataTypeDefClause?
  	dataThreadLocalClause?
  	(
  		dataPictureClause
  		| dataCommonOwnLocalClause
  		| dataTypeClause
  		| dataUsingClause
  		| dataValueClause
  		| dataUsageClause
  		| dataOccursClause
  