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Synchronous concurrency: Difference between revisions
Add Mercury.
(→{{header|Go}}: As documented, bufio.ReadString is preferred over bufio.ReadLine, this also removes the issue with long lines) |
(Add Mercury.) |
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end
</lang>
=={{header|Mercury}}==
<lang Mercury>:- module synchronous_concurrency.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is cc_multi.
:- implementation.
:- import_module int, list, string, thread, thread.channel, thread.mvar.
:- type line_or_stop
---> line(string)
; stop.
main(!IO) :-
io.open_input("input.txt", Res, !IO),
(
Res = ok(Input),
channel.init(Channel, !IO),
mvar.init(MVar, !IO),
thread.spawn(writer(Channel, MVar, 0), !IO),
reader(Input, Channel, MVar, !IO)
;
Res = error(Err),
io.format("Error opening file: %s\n", [s(io.error_message(Err))], !IO)
).
:- pred reader(io.text_input_stream::in, channel(line_or_stop)::in, mvar(int)::in,
io::di, io::uo) is det.
reader(Input, Channel, MVar, !IO) :-
io.read_line_as_string(Input, Res, !IO),
(
Res = ok(Line),
channel.put(Channel, line(Line), !IO),
reader(Input, Channel, MVar, !IO)
;
Res = eof,
channel.put(Channel, stop, !IO),
mvar.take(MVar, Count, !IO),
io.format("%d lines printed.\n", [i(Count)], !IO)
;
Res = error(Err),
channel.put(Channel, stop, !IO),
io.format("Error reading file: %s\n", [s(io.error_message(Err))], !IO)
).
:- pred writer(channel(line_or_stop)::in, mvar(int)::in, int::in,
io::di, io::uo) is cc_multi.
writer(Channel, MVar, Count, !IO) :-
channel.take(Channel, LineOrStop, !IO),
(
LineOrStop = line(Line),
io.write_string(Line, !IO),
writer(Channel, MVar, Count + 1, !IO)
;
LineOrStop = stop,
mvar.put(MVar, Count, !IO)
).</lang>
=={{header|OCaml}}==
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