aboutsummaryrefslogtreecommitdiffstats
path: root/system/doc/tutorial/complex1.erl
blob: 7bad93f7d39e6ef3954ebf15683d8bc241e1108f (plain) (blame)
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
-module(complex1).
-export([start/1, stop/0, init/1]).
-export([foo/1, bar/1]).

start(ExtPrg) ->
    spawn(?MODULE, init, [ExtPrg]).
stop() ->
    complex ! stop.

foo(X) ->
    call_port({foo, X}).
bar(Y) ->
    call_port({bar, Y}).

call_port(Msg) ->
    complex ! {call, self(), Msg},
    receive
	{complex, Result} ->
	    Result
    end.

init(ExtPrg) ->
    register(complex, self()),
    process_flag(trap_exit, true),
    Port = open_port({spawn, ExtPrg}, [{packet, 2}]),
    loop(Port).

loop(Port) ->
    receive
	{call, Caller, Msg} ->
	    Port ! {self(), {command, encode(Msg)}},
	    receive
		{Port, {data, Data}} ->
		    Caller ! {complex, decode(Data)}
	    end,
	    loop(Port);
	stop ->
	    Port ! {self(), close},
	    receive
		{Port, closed} ->
		    exit(normal)
	    end;
	{'EXIT', Port, Reason} ->
	    exit(port_terminated)
    end.

encode({foo, X}) -> [1, X];
encode({bar, Y}) -> [2, Y].

decode([Int]) -> Int.