42 lines
1.3 KiB
Prolog
42 lines
1.3 KiB
Prolog
:- multifile(func/3).
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func(fork, [F, G|S], [X, Y|S]) :-
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fork(F, S, R, ChildPID), % Send F off to the child,
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thun(G, S, [Y|_]), % Run G locally,
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read_pipe(R, X), % Collect the result from F,
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wait(ChildPID, Status). % FIXME check status!!!
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fork(Expr, Stack, In, ChildPID) :-
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mkpipe(In, Out),
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fork_prolog(ChildPID),
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korf(ChildPID, In, Out, Expr, Stack).
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korf(0, In, Out, Expr, Stack) :- close(In), % In the child.
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thun(Expr, Stack, [Result|_]),
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w(Out, Result), close(Out),
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halt.
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korf(PID, _, Out, _, _) :- % In the parent.
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integer(PID), PID =\= 0,
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close(Out).
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read_pipe(In, Result) :- % select/5, read the pipe or timeout.
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select([In], R, [], _, 1500),
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read_pipe_(R, In, Result),
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close(In).
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read_pipe_([In], In, Result) :- read(In, Result).
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read_pipe_( [], _, timeout).
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mkpipe(In, Out) :-
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create_pipe(In, Out),
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set_stream_buffering(Out, none),
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set_stream_buffering(In, none).
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w(Out, Term) :- % To get a term written out and recognized,
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write(Out, Term), % you write it to the stream
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put_code(Out, 0'.), % add a period at the end
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nl(Out), % and a newline even if you set buffering
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flush_output(Out). % to none, then flush for good measure.
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