From 1d2cad454517118cf974447ac521748247341aae Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@dcc.fc.up.pt>
Date: Mon, 13 Jun 2011 01:42:45 +0100
Subject: [PATCH] add main.pl

---
 LGPL/Makefile.in |   1 +
 LGPL/main.pl     | 114 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 LGPL/main.pl

diff --git a/LGPL/Makefile.in b/LGPL/Makefile.in
index 6bd3a00ed..d7e993fb8 100644
--- a/LGPL/Makefile.in
+++ b/LGPL/Makefile.in
@@ -28,6 +28,7 @@ PROGRAMS= $(srcdir)/base64.pl \
 	$(srcdir)/broadcast.pl \
 	$(srcdir)/date.pl \
 	$(srcdir)/debug.pl \
+	$(srcdir)/main.pl \
 	$(srcdir)/maplist.pl \
 	$(srcdir)/nb_set.pl \
 	$(srcdir)/operators.pl \
diff --git a/LGPL/main.pl b/LGPL/main.pl
new file mode 100644
index 000000000..0c3a80bdc
--- /dev/null
+++ b/LGPL/main.pl
@@ -0,0 +1,114 @@
+/*  $Id$
+
+    Part of SWI-Prolog
+
+    Author:        Jan Wielemaker
+    E-mail:        J.Wielemaker@cs.vu.nl
+    WWW:           http://www.swi-prolog.org
+    Copyright (C): 1985-2011, University of Amsterdam
+			      VU University Amsterdam
+
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; either version 2
+    of the License, or (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    As a special exception, if you link this library with other files,
+    compiled with a Free Software compiler, to produce an executable, this
+    library does not by itself cause the resulting executable to be covered
+    by the GNU General Public License. This exception does not however
+    invalidate any other reasons why the executable file might be covered by
+    the GNU General Public License.
+*/
+
+:- module(prolog_main,
+	  [ main/0
+	  ]).
+:- use_module(library(lists)).
+
+/** <module> Provide entry point for scripts
+
+This library is intended for supporting   PrologScript on Unix using the
+=|#!|= magic sequence for scripts using   commandline options. The entry
+point main/0 calls the user-supplied predicate  main/1 passing a list of
+commandline options. Below is `echo' in   Prolog  (adjust /usr/bin/pl to
+where SWI-Prolog is installed)
+
+==
+#!/usr/bin/pl -q -g main -s
+
+main(Argv) :-
+	echo(Argv).
+
+echo([]) :- nl.
+echo([Last]) :- !,
+	write(Last), nl.
+echo([H|T]) :-
+	write(H), write(' '),
+	echo(T).
+==
+
+@see	XPCE users should have a look at library(pce_main), which
+	starts the GUI and processes events until all windows have gone.
+*/
+
+:- module_transparent
+	main/0.
+
+%%	main
+%
+%	Call main/1 using the passed command-line arguments.
+
+main :-
+	context_module(M),
+	set_signals,
+	argv(Av),
+	run_main(M, Av).
+
+%%	run_main(+Module, +Args)
+%
+%	Run the main routine, guarding for exceptions and failure of the
+%	main/1 routine
+
+run_main(Module, Av) :-
+	(   catch(call(Module:main, Av), E, true)
+	->  (   var(E)
+	    ->	halt(0)
+	    ;	print_message(error, E),
+		halt(1)
+	    )
+	;   print_message(error, goal_failed(main(Av))),
+	    halt(1)
+	).
+
+argv(Av) :-
+	current_prolog_flag(argv, Argv),
+	(   append(_, [--|Av], Argv)
+	->  true
+	;   current_prolog_flag(dialect, yap)
+	->  Argv = Av
+	;   current_prolog_flag(windows, true)
+	->  Argv = [_Prog|Av]
+	;   Av = []
+	).
+
+set_signals :-
+	on_signal(int, _, interrupt).
+
+%%	interrupt(+Signal)
+%
+%	We received an interrupt.  This handler is installed using
+%	on_signal/3.
+
+interrupt(_Sig) :-
+	halt(1).
+