anchor.diff:  ;
   
   programName :
  -	cobolWord
  +	cobolWord | NONNUMERICLITERAL
   ;
   
   qualifiedDataName :
  
positive.code: callStatement :
  	CALL (identifier | literal)
  	(
  		USING (callByReferenceStatement | callByContentStatement)+
  	)?
  	(ON? OVERFLOW statements)?
  	onExceptionClause?
  
negative.code: 
  callByReferenceStatement :
  	(BY? REFERENCE)? (identifier | ADDRESS OF identifier | fileName)+ 
  ;
  
  callByValueStatement :
  	BY? VALUE identifier+ 
  ;
  
  callByContentStatement :
  