From cca1461747a55a49f4fdd40fb3b1fdddeb25a7e7 Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@dcc.fc.up.pt>
Date: Wed, 3 Nov 2010 09:45:18 +0000
Subject: [PATCH] reentrant maxval and minval.

---
 packages/meld/meldi.yap | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/packages/meld/meldi.yap b/packages/meld/meldi.yap
index 17b6b4885..62e9ea388 100644
--- a/packages/meld/meldi.yap
+++ b/packages/meld/meldi.yap
@@ -226,17 +226,26 @@ minval(V,_,GMax) :-
 	nb_getval(min_arg, V.GMax).
 	
 
-maxval(_,_,_) :-
-	nb_setval(max, -inf),
-	nb_setval(max_arg, '$none'),
-	fail.
 maxval(V,G,GMax) :-
-	call(G),
-	nb_getval(max, V0),
-	V > V0,
-	nb_setval(max, V),
-	nb_setval(max_arg, V.GMax),
-	fail.
-maxval(V,_,GMax) :-
-	nb_getval(max_arg, V.GMax).
+	Memory = f(-inf,[]),
+	(
+	 call(G),
+	 arg(1, Memory, V0),
+	 V > V0,
+	 nb_setarg(1, Memory, V),
+	 nb_setarg(2, Memory, V.GMax)
+	 ;
+	 arg(2, Memory, V.GMax)
+	).
 
+minval(V,G,GMin) :-
+	Memory = f(+inf,[]),
+	(
+	 call(G),
+	 arg(1, Memory, V0),
+	 V < V0,
+	 nb_setarg(1, Memory, V),
+	 nb_setarg(2, Memory, V.GMin)
+	 ;
+	 arg(2, Memory, V.GMin)
+	).