anchor.diff:  	// empty statement
       |	SEMI
         
  -      //assertion
  -    |   assertCondition
  -	)
  +      //assertion, checks invariants too for the class definitions allowed in statement
  +    |   assertOrInvariantCondition
       ;
   
   
  
positive.code: 
  
  statement
  // A list of statements in curly braces -- start a new scope!
      :
  	//(assertCondition)*
  	
  	(
  	compoundStatement
  
  	// class definition
      |	classDefinition
  
negative.code: 
      // A compilation unit starts with an optional package definition and
      // possibly some javadoc comments
      ( {_parseSection==0}? (invariantCondition)* packageName=packageDefinition )?
      {
        //Now we just need to check to make sure the destination file is older
        if(!getSymtab().isDestinationOlderThanCurrentFile(packageName)) {
  