RosettaCodeData/Task/Inverted-syntax/Mercury/inverted-syntax-1.mercury

:- pred progress(int::in, int::in, int::out, int::out) is det.
progress(Past, Future, At, Total) :-
	At = Past + 1,
	Total = Past + Future.

progress(Past, Future, At, Total) :-
        Past + Future = Total,
        Past + 1 = At.