anchor.diff:  predictProcedurecallAssign
       : ID LPAREN ;
   
  -procedurecallAssign returns [StringTemplate code=template("call")]
  +procedurecallCode returns [StringTemplate code=template("call")]
   {StringTemplate f=null;}
       :
           procedureInvocation[code]
  
positive.code:     id=identifier
      ASSIGN
      (
        (predictProcedurecallAssign) => code=procedurecallAssign
          { StringTemplate o = template("returnParam");
            o.setAttribute("name",id);
            code.setAttribute("outputs",o);
  
negative.code:         RPAREN
          SEMI
      ;
  
  predictProcedurecallDecl
  { StringTemplate dummy=template("call"); }
  