33 lines
751 B
Erlang
33 lines
751 B
Erlang
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-module(chapter12).
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-compile(exportall).
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-export([start/2, registrar/0]).
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registrar(Client, {Name, Fun}) ->
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case whereis(Name) of
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undefined ->
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Pid = spawn(Fun),
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register(Name, Pid),
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Client ! {ok, Name, Pid};
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Pid -> Client ! {error, exists, Pid}
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end.
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registrar() ->
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receive
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{Client, {Name, Fun}} ->
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registrar(Client, {Name, Fun}),
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registrar();
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X -> io:format("Spurious message ~w received~n", [X])
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end.
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start(AnAtom, Fun) ->
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%% start the registrar if it's not been started.
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case whereis(registrar_proc) of
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undefined ->
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Pid = spawn(chapter12, registrar, []),
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register(registrar_proc, Pid);
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_ -> void
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end,
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registrar_proc ! {self(), {AnAtom, Fun}},
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receive X -> X end.
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