From 1df8d979cdcad37840041b376fc781e12b171729 Mon Sep 17 00:00:00 2001
From: vsc <vsc@b08c6af1-5177-4d33-ba66-4b1c6b8b522a>
Date: Mon, 19 Nov 2001 17:53:19 +0000
Subject: [PATCH] remove_duplicates should keep order

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@186 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
---
 library/lists.yap | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/library/lists.yap b/library/lists.yap
index 2d7fb8719..daf0ef7aa 100644
--- a/library/lists.yap
+++ b/library/lists.yap
@@ -222,8 +222,10 @@ prefix([Elem | Rest_of_part], [Elem | Rest_of_whole]) :-
 %   removes duplicated elements from List.  Beware: if the List has
 %   non-ground elements, the result may surprise you.
 
-remove_duplicates(List, Pruned) :-
-	sort(List, Pruned).
+remove_duplicates([], []).
+remove_duplicates([Elem|L], [Elem|NL]) :-
+	delete(L, Elem, Temp),
+	remove_duplicates(Temp, NL).
 
 %   reverse(List, Reversed)
 %   is true when List and Reversed are lists with the same elements