erlangに触り始めて一日目のヤツが書く超簡易クローラ

-module(crawler).
-export([ crawl/1, crawl_exec/1, fetch/2, data_receive/1 ]).

%This is the first time to writing in Erlang.
%So now, I can only write simply...

crawl(List) ->
    crawl_exec(List),
    data_receive(length(List)).

crawl_exec([]) ->
    ok;
crawl_exec([Url|List]) ->
    spawn(crawler, fetch, [self(), Url]),
    crawl_exec(List).

fetch(Pid, Url) ->
    {ok, {{_, Status, _}, _, _}} = http:request(Url),
    Pid ! {Status, Url}.

data_receive(0) ->
    complete;
data_receive(N) ->
    receive
        {Status, Url} ->
            io:format("~b ~s~n", [Status, Url]),
            data_receive(N - 1)
    after 3000 ->
            timeout
    end.

1> Urls = ["http://www.erlang.org/", "http://en.wikipedia.org/wiki/Erlang_programming_language"].
["http://www.erlang.org/",
 "http://en.wikipedia.org/wiki/Erlang_programming_language"]
2> c(crawler).
{ok,crawler}
3> crawler:crawl(Urls).

=INFO REPORT==== 20-May-2007::02:16:50 ===
The inets application was not started. Has now been started as a temporary application.

=INFO REPORT==== 20-May-2007::02:16:50 ===
The inets application was not started. Has now been started as a temporary application.
200 http://en.wikipedia.org/wiki/Erlang_programming_language
200 http://www.erlang.org/
complete

　とりあえず、キモであるプロセスの生成や、メッセージの受け渡しの基本的な部分はおおよそ分かった。