From: notoria <notoria@users.noreply.github.com>
Date: Mon, 8 Jan 2024 20:50:02 +0000 (+0100)
Subject: Special case for `(^)/2`
X-Git-Tag: v0.9.4~36^2
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=902cd5c3eadf8deb52a25bbfe199a9dacdb2b12b;p=scryer-prolog.git

Special case for `(^)/2`

The only solutions for `Z #= X^Z` are `X = Z, X in -1\/1`. Also helps
avoid big numbers.
---

diff --git a/src/lib/clpz.pl b/src/lib/clpz.pl
index 8c21a6e9..57309470 100644
--- a/src/lib/clpz.pl
+++ b/src/lib/clpz.pl
@@ -5454,6 +5454,7 @@ run_propagator(pexp(X,Y,Z,Morph), MState) -->
             morph_into_propagator(MState, [Y,Z], reified_eq(1,Y,1,0,[],Z), Morph)
         ;   Y == 0 -> kill(MState), Z = 1
         ;   Y == 1 -> kill(MState), Z = X
+        ;   Y == Z -> kill(MState), X = Y, queue_goal(X in -1\/1)
         ;   nonvar(X) ->
             (   nonvar(Y) ->
                 (   Y >= 0 -> true ; X =:= -1 ),