(define (my-if cond t f) (if cond (t) (f)))

(my-if #t (lambda () ....) (lambda () ....))

The trickyness about if lies in the order of argument evaluation. If you ignore that, then it is relatively easy to implement if in any reasonable language. Even C (I had to leave out the function pointer types, as I haven't worked with c in a few years, and forget the syntax):

void my_if(bool cond, t, f) { if(cond) { t(); } else { f(); } }

void if_true() { ... } void if_false() {

}

my_if(true, if_true, if_false);

Point being, I think redxaxder may have been coming from a scheme background, realizing that if needs to be a builtin. It would indeed be fancy to be able to implement an if that doesn't rely upon other logical branching, though!