add support for with_output_to/2.
This commit is contained in:
Vitor Santos Costa
parent
660ea12537
commit
5b1a2067f9
22
C/iopreds.c
22
C/iopreds.c
@ -1406,8 +1406,8 @@ ConsoleSocketGetc(int sno)
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static int
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PipeGetc(int sno)
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{
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register StreamDesc *s = &Stream[sno];
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register Int ch;
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StreamDesc *s = &Stream[sno];
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Int ch;
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char c;
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/* should be able to use a buffer */
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@ -1426,7 +1426,11 @@ PipeGetc(int sno)
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} else if (count > 0) {
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ch = c;
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} else {
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Yap_Error(SYSTEM_ERROR, TermNil, "read");
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#if HAVE_STRERROR
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Yap_Error(SYSTEM_ERROR, TermNil, "at pipe getc: %s", strerror(errno));
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#else
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Yap_Error(SYSTEM_ERROR, TermNil, "at pipe getc");
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#endif
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return post_process_eof(s);
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}
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return post_process_read_char(ch, s);
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@ -4010,14 +4014,16 @@ static Int
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Stream[inp_stream].stream_getc = PlUnGetc;
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Stream[inp_stream].och = ungetc_oldc;
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}
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if (Stream[inp_stream].status & InMemory_Stream_f) {
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Stream[inp_stream].u.mem_string.pos = cpos;
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} else {
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if (seekable) {
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if (Stream[inp_stream].status & InMemory_Stream_f) {
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Stream[inp_stream].u.mem_string.pos = cpos;
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} else if (Stream[inp_stream].status) {
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#if HAVE_FGETPOS
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fsetpos(Stream[inp_stream].u.file.file, &rpos);
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fsetpos(Stream[inp_stream].u.file.file, &rpos);
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#else
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fseek(Stream[inp_stream].u.file.file, cpos, 0L);
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fseek(Stream[inp_stream].u.file.file, cpos, 0L);
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#endif
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}
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}
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if (Yap_Error_TYPE == OUT_OF_TRAIL_ERROR) {
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Yap_Error_TYPE = YAP_NO_ERROR;
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42
docs/yap.tex
42
docs/yap.tex
@ -1,4 +1,4 @@
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a\input texinfo @c -*- mode: texinfo; coding: latin-1; -*-
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´a\input texinfo @c -*- mode: texinfo; coding: latin-1; -*-
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@c %**start of header
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@setfilename yap.info
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@ -4995,6 +4995,46 @@ Print formatted output to the current output stream.
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@cnindex format/3
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Print formatted output to stream @var{S}.
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@item with_output_to(+@var{Ouput},:@var{Goal})
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@findex with_output_to/2
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@saindex with_output_to/2
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@cnindex with_output_to/2
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Run @var{Goal} as @code{once/1}, while characters written to the current
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output are sent to @var{Output}. The predicate is SWI-Prolog
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specific.
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Applications should generally avoid creating atoms by breaking and
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concatenating other atoms as the creation of large numbers of
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intermediate atoms generally leads to poor performance, even more so in
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multi-threaded applications. This predicate supports creating
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difference-lists from character data efficiently. The example below
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defines the DCG rule @code{term/3} to insert a term in the output:
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@example
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term(Term, In, Tail) :-
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with_output_to(codes(In, Tail), write(Term)).
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?- phrase(term(hello), X).
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X = [104, 101, 108, 108, 111]
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@end example
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@table @code
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@item A Stream handle or alias
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Temporary switch current output to the given stream. Redirection using with_output_to/2 guarantees the original output is restored, also if Goal fails or raises an exception. See also call_cleanup/2.
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@item atom(-@var{Atom})
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Create an atom from the emitted characters. Please note the remark above.
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@item string(-@var{String})
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Create a string-object (not supported in YAP).
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@item codes(-@var{Codes})
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Create a list of character codes from the emitted characters, similar to atom_codes/2.
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@item codes(-@var{Codes}, -@var{Tail})
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Create a list of character codes as a difference-list.
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@item chars(-@var{Chars})
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Create a list of one-character-atoms codes from the emitted characters, similar to atom_chars/2.
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@item chars(-@var{Chars}, -@var{Tail})
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Create a list of one-character-atoms as a difference-list.
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@end table
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@end table
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@ -597,6 +597,7 @@ source_module(Mod) :-
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use_module(?,:,?),
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when(?,:),
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with_mutex(+,:),
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with_output_to(?,:),
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(: -> :),
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(: *-> :),
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(: ; :),
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60
pl/yio.yap
60
pl/yio.yap
@ -1061,7 +1061,7 @@ current_stream(File, Opts, Stream) :-
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'$extend_file_search_path'(P) :-
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atom_codes(P,S),
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'$env_separator'(ES),
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'$split_for_path'(S,0'=,ES,Paths),
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'$split_for_path'(S,0'=,ES,Paths), %'
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'$add_file_search_paths'(Paths).
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'$split_for_path'([], _, _, []).
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@ -1152,4 +1152,60 @@ prolog_file_name(File, PrologFileName) :-
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prolog_file_name(File, PrologFileName) :-
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'$do_error'(type_error(atom,T), prolog_file_name(File, PrologFileName)).
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s
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with_output_to(Output, Command) :-
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setup_call_cleanup( '$setup_wot'(Output, Stream, OldStream, with_output_to(Output, Command)),
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once(Command),
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'$cleanup_wot'(Output, Stream, OldStream) ).
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'$setup_wot'(Output, Stream, OldStream, Goal) :-
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'$setup_wot'(Output, Stream, Goal),
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current_output(OldStream),
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set_output(Stream).
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'$setup_wot'(Output, Stream, Goal) :-
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var(Output), !,
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'$do_error'(instantiation_error,Goal).
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'$setup_wot'(atom(_Atom), Stream, _) :- !,
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charsio:open_mem_write_stream(Stream).
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'$setup_wot'(codes(_Codes), Stream, _) :- !,
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charsio:open_mem_write_stream(Stream).
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'$setup_wot'(codes(_Codes, _Tail), Stream, _) :- !,
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charsio:open_mem_write_stream(Stream).
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'$setup_wot'(chars(_Chars), Stream, _) :- !,
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charsio:open_mem_write_stream(Stream).
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'$setup_wot'(chars(_Chars, _Tail), Stream, _) :- !,
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charsio:open_mem_write_stream(Stream).
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'$setup_wot'(Stream, Stream, _) :-
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'$stream'(Stream), !.
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'$setup_wot'(Output, _, Goal) :-
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'$do_error'(type_error(output,Output),Goal).
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'$cleanup_wot'(Output, Stream, OldStream) :- !,
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'$cleanup_wot'(Output, Stream),
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set_output(OldStream).
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'$cleanup_wot'(atom(Atom), Stream) :- !,
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charsio:peek_mem_write_stream(Stream, [], String),
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atom_codes(Atom, String),
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close(Stream).
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'$cleanup_wot'(codes(Codes), Stream) :- !,
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charsio:peek_mem_write_stream(Stream, [], Codes),
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close(Stream).
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'$cleanup_wot'(codes(Codes, Tail), Stream) :- !,
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charsio:peek_mem_write_stream(Stream, Tail, Codes),
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close(Stream).
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'$cleanup_wot'(chars(Chars), Stream) :- !,
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charsio:peek_mem_write_stream(Stream, [], String),
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'$codes_to_chars'([], String, Chars),
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close(Stream).
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'$cleanup_wot'(chars(Chars, Tail), Stream) :- !,
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charsio:peek_mem_write_stream(Stream, Tail, String),
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'$codes_to_chars'(Tail, String, Chars),
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close(Stream).
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'$cleanup_wot'(_, _).
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'$codes_to_chars'(String0, String, String0) :- String0 == String, !.
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'$codes_to_chars'(String0, [Code|String], [Char|Chars]) :-
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atom_codes(Char, [Code]),
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'$codes_to_chars'(String0, String, Chars).
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