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yap-6.3/library/charsio.yap

118 lines
3.0 KiB
Prolog

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: charsio.yap *
* Last rev: 5/12/99 *
* mods: *
* comments: I/O on character strings *
* *
*************************************************************************/
:- module(charsio, [
format_to_chars/3,
format_to_chars/4,
write_to_chars/3,
write_to_chars/2,
atom_to_chars/3,
atom_to_chars/2,
number_to_chars/3,
number_to_chars/2,
read_from_chars/2,
open_chars_stream/2,
with_output_to_chars/2,
with_output_to_chars/3,
with_output_to_chars/4,
term_to_atom/2
]).
:- meta_predicate(with_output_to_chars(0,?)).
:- meta_predicate(with_output_to_chars(0,-,?)).
:- meta_predicate(with_output_to_chars(0,-,?,?)).
format_to_chars(Form, Args, OUT) :-
format_to_chars(Form, Args, OUT, []).
format_to_chars(Form, Args, OUT, L0) :-
open_mem_write_stream(Stream),
format(Stream,Form,Args),
peek_mem_write_stream(Stream, L0, O),
close(Stream),
O = OUT.
write_to_chars(Term, OUT) :-
write_to_chars(Term, [], OUT).
atom_to_chars(Atom, OUT) :-
atom_to_chars(Atom, [], OUT).
atom_to_chars(Atom, L0, OUT) :-
var(Atom), !,
throw(error(instantiation_error,atom_to_chars(Atom, L0, OUT))).
atom_to_chars(Atom, L0, OUT) :-
atom(Atom), !,
open_mem_write_stream(Stream),
write(Stream, Atom),
peek_mem_write_stream(Stream, L0, O),
close(Stream),
O = OUT.
atom_to_chars(Atom, L0, OUT) :-
throw(error(type_error(atom,Atom),atom_to_chars(Atom, L0, OUT))).
number_to_chars(Number, OUT) :-
number_to_chars(Number, [], OUT).
number_to_chars(Number, L0, OUT) :-
var(Number), !,
throw(error(instantiation_error,number_to_chars(Number, L0, OUT))).
number_to_chars(Number, L0, OUT) :-
number(Number), !,
open_mem_write_stream(Stream),
write(Stream, Number),
peek_mem_write_stream(Stream, L0, O),
close(Stream),
O = OUT.
number_to_chars(Number, L0, OUT) :-
throw(error(type_error(number,Number),number_to_chars(Number, L0, OUT))).
open_chars_stream(Chars, Stream) :-
open_mem_read_stream(Chars, Stream).
with_output_to_chars(Goal, Chars) :-
with_output_to_chars(Goal, [], Chars).
with_output_to_chars(Goal, L0, Chars) :-
with_output_to_chars(Goal, Stream, L0, Chars),
close(Stream).
with_output_to_chars(Goal, Stream, L0, Chars) :-
open_mem_write_stream(Stream),
current_output(SO),
set_output(Stream),
do_output_to_chars(Goal, Stream, L0, Chars, SO).
do_output_to_chars(Goal, Stream, L0, Chars, SO) :-
catch(Goal, Exception, handle_exception(Exception,Stream,SO)),
!,
set_output(SO),
peek_mem_write_stream(Stream, L0, Chars).
do_output_to_chars(_Goal, Stream, _L0, _Chars, SO) :-
set_output(SO),
close(Stream),
fail.
handle_exception(Exception, Stream, SO) :-
close(Stream),
current_output(SO),
throw(Exception).