concrete ArithmeticEng of Arithmetic = {

lincat
    Answer, Object, Question = Str;

lin Even object = is "even " object;
    Odd object = is "odd" object;
    Prime object = is "prime" object;
    Number int = int.s;
    No  = "No.";
    Yes  = "Yes.";

oper is : Str -> Str -> Str  = \ pred,obj -> "is"++obj++pred++"?";
}