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yap-6.3/swi/library/main.pl
2013-03-05 15:50:38 -06:00

115 lines
3.0 KiB
Prolog

/* $Id$
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).