67 lines
1.3 KiB
Plaintext
67 lines
1.3 KiB
Plaintext
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:- category(using). % we can call the threaded_wait/1 and threaded_notify/1 predicates from category
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% predicates; the importing object threads are used for exchanging notifications
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:- public([pick_up/0, release/0]).
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pick_up :-
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threaded_wait(free). % wait until the tool is available
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release :-
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threaded_notify(free). % notify that the tool is now available
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:- end_category.
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:- object(chalk,
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imports(using)).
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:- threaded. % the chalk's thread is used for exchanging notifications
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:- initialization(::release). % make the chalk initially available
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:- end_object.
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:- object(eraser,
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imports(using)).
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:- threaded. % the eraser's thread is used for exchanging notifications
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:- initialization(::release). % make the eraser initially available
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:- end_object.
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:- category(running). % in alternative to a category we could also have defined a class
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:- public(run/1).
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run(0) :-
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!.
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run(N) :-
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N > 0,
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eraser::pick_up,
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chalk::pick_up,
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self(Self),
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write(Self), write(' is writing...'), nl,
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random::random(1, 5, Random), % simulate a variable time
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thread_sleep(Random), % spending on writing
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chalk::release,
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eraser::release,
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N2 is N - 1,
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run(N2).
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:- end_category.
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:- object(teacher,
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imports(running)).
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:- end_object.
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:- object(student,
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imports(running)).
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:- end_object.
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