File r37/lisp/csl/jlisp/NullFn.java artifact 2e904028c9 part of check-in a57e59ec0d

//24/02/02 created for seeing if I have all tools necessary for Lisp

class NullFn extends BuiltinFunction
{
    public LispObject op1(LispObject arg1)
    {
        return arg1 == Jlisp.nil ?
               Jlisp.lispTrue :
               Jlisp.nil;
    }
}