/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2009-2015, University of Amsterdam VU University Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(charsio, [ format_to_chars/3, % +Format, +Args, -Codes format_to_chars/4, % +Format, +Args, -Codes, ?Tail write_to_chars/2, % +Term, -Codes write_to_chars/3, % +Term, -Codes, ?Tail atom_to_chars/2, % +Atom, -Codes atom_to_chars/3, % +Atom, -Codes, ?Tail number_to_chars/2, % +Number, -Codes number_to_chars/3, % +Number, -Codes, ?Tail % read predicates read_from_chars/2, % +Codes, -Term read_term_from_chars/3, % +Codes, -Term, +Options open_chars_stream/2, % +Codes, -Stream with_output_to_chars/2, % :Goal, -Codes with_output_to_chars/3, % :Goal, -Codes, ?Tail with_output_to_chars/4 % :Goal, -Stream, -Codes, ?Tail ]). :- autoload(library(error),[must_be/2]). :- meta_predicate with_output_to_chars(0, -), with_output_to_chars(0, -, ?), with_output_to_chars(0, -, -, ?). :- predicate_options(read_term_from_chars/3, 3, [pass_to(system:read_term/3, 3)]). /** I/O on Lists of Character Codes This module emulates the Quintus/SICStus library charsio.pl for reading and writing from/to lists of character codes. Most of these predicates are straight calls into similar SWI-Prolog primitives. Some can even be replaced by ISO standard predicates. @compat The naming of this library is not in line with the ISO standard. We believe that the SWI-Prolog native predicates form a more elegant alternative for this library. */ %! format_to_chars(+Format, +Args, -Codes) is det. % % Use format/2 to write to a list of character codes. format_to_chars(Format, Args, Codes) :- format(codes(Codes), Format, Args). %! format_to_chars(+Format, +Args, -Codes, ?Tail) is det. % % Use format/2 to write to a difference list of character codes. format_to_chars(Format, Args, Codes, Tail) :- format(codes(Codes, Tail), Format, Args). %! write_to_chars(+Term, -Codes) % % Write a term to a code list. True when Codes is a list of % character codes written by write/1 on Term. write_to_chars(Term, Codes) :- format(codes(Codes), '~w', [Term]). %! write_to_chars(+Term, -Codes, ?Tail) % % Write a term to a code list. Codes\Tail is a difference list of % character codes produced by write/1 on Term. write_to_chars(Term, Codes, Tail) :- format(codes(Codes, Tail), '~w', [Term]). %! atom_to_chars(+Atom, -Codes) is det. % % Convert Atom into a list of character codes. % % @deprecated Use ISO atom_codes/2. atom_to_chars(Atom, Codes) :- atom_codes(Atom, Codes). %! atom_to_chars(+Atom, -Codes, ?Tail) is det. % % Convert Atom into a difference list of character codes. atom_to_chars(Atom, Codes, Tail) :- format(codes(Codes, Tail), '~a', [Atom]). %! number_to_chars(+Number, -Codes) is det. % % Convert Atom into a list of character codes. % % @deprecated Use ISO number_codes/2. number_to_chars(Number, Codes) :- number_codes(Number, Codes). %! number_to_chars(+Number, -Codes, ?Tail) is det. % % Convert Number into a difference list of character codes. number_to_chars(Number, Codes, Tail) :- must_be(number, Number), format(codes(Codes, Tail), '~w', [Number]). %! read_from_chars(+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_chars([], end_of_file) :- !. read_from_chars(List, Term) :- atom_to_term(List, Term, _). %! read_term_from_chars(+Codes, -Term, +Options) is det. % % Read Codes into Term. Options are processed by read_term/3. % % @compat sicstus read_term_from_chars(Codes, Term, Options) :- read_term_from_atom(Codes, Term, Options). %! open_chars_stream(+Codes, -Stream) is det. % % Open Codes as an input stream. % % @see open_string/2. open_chars_stream(Codes, Stream) :- open_string(Codes, Stream). %! with_output_to_chars(:Goal, -Codes) is det. % % Run Goal as with once/1. Output written to =current_output= % is collected in Codes. with_output_to_chars(Goal, Codes) :- with_output_to(codes(Codes), Goal). %! with_output_to_chars(:Goal, -Codes, ?Tail) is det. % % Run Goal as with once/1. Output written to =current_output= % is collected in Codes\Tail. with_output_to_chars(Goal, Codes, Tail) :- with_output_to(codes(Codes, Tail), Goal). %! with_output_to_chars(:Goal, -Stream, -Codes, ?Tail) is det. % % Same as with_output_to_chars/3 using an explicit stream. The % difference list Codes\Tail contains the character codes that % Goal has written to Stream. with_output_to_chars(Goal, Stream, Codes, Tail) :- with_output_to(codes(Codes, Tail), with_stream(Stream, Goal)). with_stream(Stream, Goal) :- current_output(Stream), call(Goal).