From: notoria <notoria@users.noreply.github.com>
Date: Sat, 14 Oct 2023 14:15:03 +0000 (+0200)
Subject: Reify (^)/2
X-Git-Tag: remove~25
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=62e6ca02f9f1ef45cdf5fe7b691469b2d6e99945;p=scryer-prolog.git

Reify (^)/2

Like (/)/2, (^)/2 can fail in cases such as 0 #==> X #= 2^(-1), where success is expected.
---

diff --git a/src/lib/clpz.pl b/src/lib/clpz.pl
index ddc2ee3e..f766771a 100644
--- a/src/lib/clpz.pl
+++ b/src/lib/clpz.pl
@@ -3571,7 +3571,8 @@ parse_reified(E, R, D,
                m(max(A,B))   => [d(D), p(pgeq(R, A)), p(pgeq(R, B)), p(pmax(A,B,R)), a(A,B,R)],
                m(min(A,B))   => [d(D), p(pgeq(A, R)), p(pgeq(B, R)), p(pmin(A,B,R)), a(A,B,R)],
                m(abs(A))     => [d(D), g(#R#>=0), p(pabs(A, R)), a(A,R)],
-               m(A^B)        => [d(D), p(pexp(A,B,R)), a(A,B,R)],
+               m(A^B)        => [d(D1), p(preified_exp(A,B,D2,R)),
+                                 p(reified_and(D1,[],D2,[],D)),a(D2),a(A,B,R)],
                m(A/B)        => [d(D1), p(preified_slash(A,B,D2,R)),
                                  p(reified_and(D1,[],D2,[],D)),a(D2),a(A,B,R)],
                m(A div B)    => [d(D1),
@@ -5939,6 +5940,35 @@ run_propagator(preified_slash(X, Y, D, R), MState) -->
         ;   []
         ).
 
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+run_propagator(preified_exp(X, Y, D, R), MState) -->
+        (   X == 1 ->
+            kill(MState),
+            D = 1,
+            R = 1
+        ;   Y == 0 ->
+            kill(MState),
+            D = 1,
+            R = 1
+        ;   Y == 1 ->
+            kill(MState),
+            D = 1,
+            R = X
+        ;   nonvar(X),
+            nonvar(Y) ->
+            kill(MState),
+            (   ( abs(X) =:= 1 ; Y >= 0 ) ->
+                D = 1,
+                R is X^Y
+            ;   D = 0
+            )
+        ;   D == 1 ->
+            kill(MState),
+            queue_goal(X^Y #= R)
+        ;   []
+        ).
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
@@ -7872,6 +7902,7 @@ attribute_goal_(reified_and(X,_,Y,_,B))    --> [#X #/\ #Y #<==> #B].
 attribute_goal_(reified_or(X, _, Y, _, B)) --> [#X #\/ #Y #<==> #B].
 attribute_goal_(reified_not(X, Y))         --> [#\ #X #<==> #Y].
 attribute_goal_(preified_slash(X, Y, _, R)) --> [#X/ #Y #= R].
+attribute_goal_(preified_exp(X, Y, _, R))  --> [#X^ #Y #= R].
 attribute_goal_(pimpl(X, Y, _))            --> [#X #==> #Y].
 attribute_goal_(pfunction(Op, A, B, R)) -->
         { Expr =.. [Op,#A,#B] },