:- object(rational,
implements(comparingp)).
:- info([
author is 'Paulo Moura',
version is 1.0,
date is 2000/4/22,
comment is 'Implements comparison between rational numbers represented as Num/Den.']).
N1/D1 < N2/D2 :-
{N1*D2 < N2*D1}.
N1/D1 =< N2/D2 :-
{N1*D2 =< N2*D1}.
N1/D1 > N2/D2 :-
{N1*D2 > N2*D1}.
N1/D1 >= N2/D2 :-
{N1*D2 >= N2*D1}.
N1/D1 =:= N2/D2 :-
{N1*D2 =:= N2*D1}.
N1/D1 =\= N2/D2 :-
{N1*D2 =\= N2*D1}.
:- end_object.
