From 4d35c1f70a35fed33a95016f2cff3ab8376904ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADtor=20Santos=20Costa?= <vsc@dcc.fc.up.pt>
Date: Fri, 14 Dec 2012 23:30:48 +0000
Subject: [PATCH] fix call to undefined halt/1.

---
 pl/boot.yap | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pl/boot.yap b/pl/boot.yap
index 33f3d4df1..2ed68f8df 100755
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -153,6 +153,7 @@ true :- true.
 
 /* main execution loop							*/
 '$read_toplevel'(Goal, Bindings) :-
+	'$pred_exists'(read_history(_,_,_,_,_,_), user),
 	'$swi_current_prolog_flag'(readline, true), !,
 	read_history(h, '!h',
                          [trace, end_of_file],
@@ -217,7 +218,7 @@ true :- true.
 	get_value('$top_level_goal',GA), GA \= [], !,
 	set_value('$top_level_goal',[]),
 	'$run_atom_goal'(GA),
-	halt(0).
+	( '$pred_exists'(halt(_), user) -> halt(0) ; '$halt'(0) ).
 '$enter_top_level' :-
 	'$disable_docreep',
 	'$run_toplevel_hooks',
@@ -228,7 +229,7 @@ true :- true.
 	nb_setval('$debug_run',off),
 	nb_setval('$debug_jump',off),
 	'$command'(Command,Varnames,_Pos,top),
-	halt(0).
+	( '$pred_exists'(halt(_), user) -> halt(0) ; '$halt'(0) ).
 
 
  '$erase_sets' :-