二郎:案例。。函数调用返回的构造?

令人高兴的是,badarg修复很容易。 io:format/2 将术语列表作为第二个参数。请参阅:

(Erlang R15B02 (erts-5.9.2) [source] [64-bit] [smp:8:8] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.2  (abort with ^G)
1> io:format("main ~p~n", 2).
** exception error: bad argument
     in function  io:format/3
        called as io:format(<0.24.0>,"main ~p~n",2)
2> io:format("main ~p~n", [2]).
main 2
ok

你的第二个问题是 ?MODULE 只返回当前模块名称的一个原子。您将要将消息发送到进程。如果您将代码修改为这样:

-module(case_).
-export([main/1, sender/2, receiver/0]).

main(Input) ->
    io:format("main ~p~n", [Input]),
    Recv = spawn(?MODULE, receiver, []),
    case sender(Recv, Input) of
        {Data} ->
            io:format("Received ~p~n", [Data])
    end.

sender(Pid, Input) ->
    io:format("sender ~p~n", [Input]),
    Ref = make_ref(),
    Pid ! { self(), Ref, {send_data, Input}},
    receive
        {Ref, ok, Data} ->
            {Data}
    end.

receiver() ->
    io:format("receiver ~n"),
    receive
        {Pid, Ref, {send_data, Input}} ->
            Pid ! { Ref, ok, Input + Input}
    end.

那么repl中的交互作用:

Erlang R15B02 (erts-5.9.2) [source] [64-bit] [smp:8:8] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.2  (abort with ^G)
1> c("case_").
{ok,case_}
2> case_:main(2).
main 2
sender 2
receiver 
Received 4
ok