From 2dce50fbd5ef72bbcd51533cf04f8722f8139d6a Mon Sep 17 00:00:00 2001
From: Peter Mikkelsen <peter@pmikkelsen.com>
Date: Thu, 8 Jul 2021 00:49:34 +0000
Subject: Add arithmetic comparison predicates

---
 stdlib.pl | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'stdlib.pl')

diff --git a/stdlib.pl b/stdlib.pl
index 596aff6..b36a851 100644
--- a/stdlib.pl
+++ b/stdlib.pl
@@ -129,3 +129,24 @@ write_canonical(Term) :-
 write_canonical(S, Term) :-
 	write_term(S, Term, [quoted(true), ignore_ops(true)]).
 
+% Arithmetic comparisons defined in terms of >=. This is not the most effective way,
+% but it is fine for now.
+
+E1 =:= E2 :-
+	E1 >= E2,
+	E2 >= E1.
+
+E1 =\= E2 :-
+	\+ E1 =:= E2.
+
+E1 < E2 :-
+	E2 >= E1,
+	E1 =\= E2.
+
+E1 =< E2 :-
+	E2 >= E1.
+
+E1 > E2 :-
+	E2 < E1.
+
+
-- 
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