/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2009-2011, 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 General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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(codesio,
[ format_to_codes/3, % +Format, +Args, -Codes
format_to_codes/4, % +Format, +Args, -Codes, ?Tail
write_to_codes/2, % +Term, -Codes
write_to_codes/3, % +Term, -Codes, ?Tail
write_term_to_codes/3, % +Term, -Codes, +Options
write_term_to_codes/4, % +Term, -Codes, ?Tail, +Options
% read predicates
read_from_codes/2, % +Codes, -Term
read_term_from_codes/3, % +Codes, -Term, +Options
open_codes_stream/2, % +Codes, -Stream
with_output_to_codes/2, % :Goal, -Codes
with_output_to_codes/3, % :Goal, -Codes, ?Tail
with_output_to_codes/4 % :Goal, -Stream, -Codes, ?Tail
]).
:- use_module(library(error)).
/* :- use_module(library(memfile)). */ % see open_codes_stream/2
:- meta_predicate
with_output_to_codes(0, -),
with_output_to_codes(0, -, ?),
with_output_to_codes(0, -, -, ?).
:- predicate_options(read_term_from_codes/3, 3,
[pass_to(system:read_term/3, 3)]).
:- predicate_options(write_term_to_codes/3, 3,
[pass_to(system:write_term/3, 3)]).
:- predicate_options(write_term_to_codes/4, 4,
[pass_to(system:write_term/3, 3)]).
/** <module> I/O on Lists of Character Codes
This module emulates the SICStus library codesio.pl for reading and
writing from/to lists of character codes. Most of these predicates are
straight calls into similar SWI-Prolog primitives.
This library is based on library(charsio) that originates from Quintus
Prolog. The naming is updated to reflect the ISO naming conventions and
the ISO predicats atom_codes/2, etc are obviously removed from this
library.
@compat SICStus 4
*/
%% format_to_codes(+Format, +Args, -Codes) is det.
%
% Use format/2 to write to a list of character codes.
format_to_codes(Format, Args, Codes) :-
format(codes(Codes), Format, Args).
%% format_to_codes(+Format, +Args, -Codes, ?Tail) is det.
%
% Use format/2 to write to a difference list of character codes.
format_to_codes(Format, Args, Codes, Tail) :-
format(codes(Codes, Tail), Format, Args).
%% write_to_codes(+Term, -Codes)
%
% Codes is a list of character codes produced by write/1 on Term.
write_to_codes(Term, Codes) :-
format(codes(Codes), '~w', [Term]).
%% write_to_codes(+Term, -Codes, ?Tail)
%
% Codes is a difference-list of character codes produced by write/1 on Term.
write_to_codes(Term, Codes, Tail) :-
format(codes(Codes, Tail), '~w', [Term]).
%% write_term_to_codes(+Term, -Codes, +Options) is det.
%
% True when Codes is a string that matches the output of
% write_term/3 using Options.
write_term_to_codes(Term, Codes, Options) :-
format(codes(Codes), '~W', [Term, Options]).
%% write_term_to_codes(+Term, -Codes, ?Tail, +Options) is det.
%
% True when Codes\Tail is a difference list containing the
% character codes that matches the output of write_term/3 using
% Options.
write_term_to_codes(Term, Codes, Tail, Options) :-
format(codes(Codes, Tail), '~W', [Term, Options]).
%% read_from_codes(+Codes, -Term) is det.
%
% Read Codes into Term.
%
% @compat The SWI-Prolog version does not require Codes to end
% in a full-stop.
read_from_codes("", end_of_file) :- !.
read_from_codes(List, Term) :-
atom_to_term(List, Term, _).
%% read_term_from_codes(+Codes, -Term, +Options) is det.
%
% Read Codes into Term. Options are processed by read_term/3.
%
% @compat sicstus
read_term_from_codes(Codes, Term, Options) :-
setup_call_cleanup(open_codes_stream(Codes, Stream, '\n.\n'),
read_term(Stream, Term0, Options),
close(Stream)),
Term = Term0.
%% open_codes_stream(+Codes, -Stream) is det.
%
% Open Codes as an input stream.
%
% @bug Depends on autoloading library(memfile). As many
% applications do not need this predicate we do not
% want to make the entire library dependent on
% autoloading.
open_codes_stream(Codes, Stream) :-
open_codes_stream(Codes, Stream, '').
open_codes_stream(Codes, Stream, Postfix) :-
new_memory_file(MF),
setup_call_cleanup(
open_memory_file(MF, write, Out),
format(Out, '~s~w', [Codes, Postfix]),
close(Out)),
open_memory_file(MF, read, Stream,
[ free_on_close(true)
]).
%% with_output_to_codes(:Goal, Codes) is det.
%
% Run Goal with as once/1. Output written to =current_output=
% is collected in Codes.
with_output_to_codes(Goal, Codes) :-
with_output_to(codes(Codes), Goal).
%% with_output_to_codes(:Goal, -Codes, ?Tail) is det.
%
% Run Goal with as once/1. Output written to =current_output=
% is collected in Codes\Tail.
with_output_to_codes(Goal, Codes, Tail) :-
with_output_to(codes(Codes, Tail), Goal).
%% with_output_to_codes(:Goal, -Stream, -Codes, ?Tail) is det.
%
% As with_output_to_codes/2, but Stream is unified with the
% temporary stream.
with_output_to_codes(Goal, Stream, Codes, Tail) :-
with_output_to(codes(Codes, Tail), with_stream(Stream, Goal)).
with_stream(Stream, Goal) :-
current_output(Stream),
call(Goal).