bounded_max_int.chr

:- module(bounded_max_int, [result/1]).
:- use_module(library(prelude)).

:- chr_constraint result(int).

:- class (gt(int, int) -> bool), (gt(float, float) -> bool).
gt(X, Y) | integer(X), integer(Y) -> X > Y.
gt(X, Y) -> X > Y.

:- function pick_max(T, T) -> T requiring gt(T, T) -> bool.

pick_max(X, Y) | gt(X, Y) -> X.
pick_max(_, Y) -> Y.

result(R) <=> R is pick_max(3, 4).