anchor.diff:      ;
   
   conditionalAndExpression returns [Expression element]
  +@after{check_null(retval.element);}
       :   ex=inclusiveOrExpression {retval.element = ex.element;} ( '&&' exx=inclusiveOrExpression 
           {retval.element = new ConditionalAndExpression(retval.element, exx.element);
            setLocation(retval.element,retval.start,exx.stop);
  
positive.code: 
  equalityExpression returns [Expression element]
  @init{String op=null;}
      :   ex=instanceOfExpression  {retval.element = ex.element;} 
            ( ('==' {op="==";} | '!=' {op="!=";}) exx=instanceOfExpression 
          {
  
negative.code:     ;
  
  inclusiveOrExpression returns [Expression element]
  @after{check_null(retval.element);}
      :   ex=exclusiveOrExpression {retval.element = ex.element;} ( '|' exx=exclusiveOrExpression 
         {
           retval.element = new InfixOperatorInvocation("|", retval.element);
  