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yap-6.3/library/charsio.yap
2011-03-11 19:48:43 +00:00

103 lines
2.8 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(Format, Args, Codes) :-
format(codes(Codes), Format, Args).
format_to_chars(Format, Args, OUT, L0) :-
format(codes(OUT, L0), Format, Args).
write_to_chars(Term, Codes) :-
format(codes(Codes), '~w', [Term]).
write_to_chars(Term, Out, Tail) :-
format(codes(Out,Tail),'~w',[Term]).
atom_to_chars(Atom, OUT) :-
atom_codes(Atom, OUT).
atom_to_chars(Atom, L0, OUT) :-
format(codes(L0, OUT), '~a', [Atom]).
number_to_chars(Number, OUT) :-
number_codes(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), !,
format(codes(L0, OUT), '~w', [Number]).
number_to_chars(Number, L0, OUT) :-
throw(error(type_error(number,Number),number_to_chars(Number, L0, OUT))).
open_chars_stream(Codes, Stream) :-
open_chars_stream(Codes, Stream, '').
open_chars_stream(Codes, Stream, Postfix) :-
predicate_property(memory_file:open_memory_file(_,_,_),_), !,
memory_file:new_memory_file(MF),
memory_file:open_memory_file(MF, write, Out),
format(Out, '~s~w', [Codes, Postfix]),
close(Out),
memory_file:open_memory_file(MF, read, Stream,
[ free_on_close(true)
]).
open_chars_stream(Codes, Stream, Postfix) :-
ensure_loaded(library(memfile)),
open_chars_stream(Codes, Stream, Postfix).
with_output_to_chars(Goal, Codes) :-
with_output_to(codes(Codes), Goal).
with_output_to_chars(Goal, Codes, L0) :-
with_output_to(codes(Codes, L0), Goal).
%% with_output_to_chars(:Goal, -Stream, -Codes, ?Tail) is det.
%
% As with_output_to_chars/2, but Stream is unified with the
% temporary 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).