/usr/share/Yap/option.pl is in yap 5.1.3-6.
This file is owned by root:root, with mode 0o644.
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Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: jan@swi.psy.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2002, University of 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(swi_option,
[ option/2, % +Term, +List
option/3, % +Term, +List, +Default
select_option/3, % +Term, +Options, -RestOpts
select_option/4 % +Term, +Options, -RestOpts, +Default
]).
:- use_module(library(lists)).
%% option(?Option, +OptionList, +Default)
%
% Get an option from a OptionList. OptionList can use the
% Name=Value as well as the Name(Value) convention.
%
% @param Option Term of the form Name(?Value).
option(Opt, Options, Default) :- % make option processing stead-fast
arg(1, Opt, OptVal),
nonvar(OptVal), !,
functor(Opt, OptName, 1),
functor(Gen, OptName, 1),
option(Gen, Options, Default),
Opt = Gen.
option(Opt, Options, _) :-
get_option(Opt, Options), !.
option(Opt, _, Default) :-
arg(1, Opt, Default).
%% option(?Option, +OptionList)
%
% Get an option from a OptionList. OptionList can use the
% Name=Value as well as the Name(Value) convention. Fails silently
% if the option does not appear in OptionList.
%
% @param Option Term of the form Name(?Value).
option(Opt, Options) :- % make option processing stead-fast
arg(1, Opt, OptVal),
nonvar(OptVal), !,
functor(Opt, OptName, 1),
functor(Gen, OptName, 1),
option(Gen, Options),
Opt = Gen.
option(Opt, Options) :-
get_option(Opt, Options), !.
get_option(Opt, Options) :-
memberchk(Opt, Options), !.
get_option(Opt, Options) :-
functor(Opt, OptName, 1),
arg(1, Opt, OptVal),
memberchk(OptName=OptVal, Options), !.
%% select_option(?Option, +Options, -RestOptions) is semidet.
%
% As option/2, removing the matching option from Options and
% unifying the remaining options with RestOptions.
select_option(Opt, Options0, Options) :- % stead-fast
arg(1, Opt, OptVal),
nonvar(OptVal), !,
functor(Opt, OptName, 1),
functor(Gen, OptName, 1),
select_option(Gen, Options0, Options),
Opt = Gen.
select_option(Opt, Options0, Options) :-
get_option(Opt, Options0, Options), !.
get_option(Opt, Options0, Options) :-
select(Opt, Options0, Options), !.
get_option(Opt, Options0, Options) :-
functor(Opt, OptName, 1),
arg(1, Opt, OptVal),
select(OptName=OptVal, Options0, Options), !.
%% select_option(?Option, +Options, -RestOptions, +Default) is det.
%
% As select_option/3, but if Option is not in Options, its value
% is unified with Default and RestOptions with Options.
select_option(Option, Options, RestOptions, _Default) :-
select_option(Option, Options, RestOptions), !.
select_option(Option, Options, Options, Default) :-
arg(1, Option, Default).
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