trivial diff: copy/2 & mercury_builtin.nu.nl

[Fergus Henderson]

Fix the handling of copy/2 for SICStus and NU-Prolog.

library/mercury_builtin.nu.nl:
	Implement copy/2 properly, using duplicate/2.
	Add unsafe_promise_unique/2 with the same semantics
	as the old copy/2.

cvs diff  library/mercury_builtin.nu.nl
Index: library/mercury_builtin.nu.nl
===================================================================
RCS file: /home/staff/zs/imp/mercury/library/mercury_builtin.nu.nl,v
retrieving revision 1.17
diff -u -r1.17 mercury_builtin.nu.nl
--- mercury_builtin.nu.nl	1997/07/27 15:06:57	1.17
+++ mercury_builtin.nu.nl	1997/10/15 07:34:32
@@ -12,7 +12,10 @@
 builtin_strcmp_2(=, 0).
 builtin_strcmp_2(>, 1).
 
-copy(X, X).
+copy(X, Y) :-
+	duplicate(X, Y).
+
+unsafe_promise_unique(X, X).
 
 unify(X, X).
 

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
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