/usr/lib/swi-prolog/library/prolog_stream.pl is in swi-prolog-nox 7.2.3-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | /* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2015, 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(prolog_stream,
[ open_prolog_stream/4 % +Module, +Mode, -Stream, +Data
]).
:- use_module(library(shlib)).
:- use_foreign_library(foreign(prolog_stream)).
/** <module> A stream with Prolog callbacks
This library defines a Prolog stream that realises its low-level I/O
with callbacks to Prolog. The library was developed to bind normal
Prolog I/O to Pengines I/O. This type of I/O redirection is probably the
primary use case.
*/
%% open_prolog_stream(+Module, +Mode, -Stream, +Options)
%
% Create a new stream that implements its I/O by calling
% predicates in Module. The called predicates are:
%
% - Module:stream_write(+Stream, +String)
% Called for a `Mode = write` stream if data is available.
% String contains the (textual) data that is written
% to Stream. The callback is called if the buffer of
% Stream overflows, the user calls flush_output(Stream)
% or Stream is closed and there is buffered data.
% - Module:stream_read(+Stream, -Term)
% Called for a `Mode == read` stream to get new data. On
% success the stream extracts text from the provided Term.
% Term is typically a string, atom, code or character list.
% If term is not one of the above, it is handed to writeq/1.
% To signal end-of-file, unify stream with an empty text,
% e.g., `stream_read(Stream, "")`.
% - Module:stream_close(+Stream)
% Called when the stream is closed. This predicate must
% succeed. The callback can be used to cleanup associated
% resources.
%
% The current implementation only deals with text streams. The
% stream uses the =wchar_t= encoding. The buffer size must be a
% multiple of =wchar_t=, i.e., a multiple of four for portability.
% The _newline_ mode of the stream is =posix= on all platforms,
% disabling the translation `"\n" --> "\r\n"`.
%
% @arg Options is currently ignored.
% @bug Futher versions might require additional callbacks. As we
% demand all callbacks to be defined, existing code needs
% to implement the new callbacks.
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