[erlang-questions] Is it better to use tuple to send the message or list or it just does not matter ?

lang qiu <>
Mon Dec 22 16:45:27 CET 2008


Hi all,
When sending message by *Pid ! Message*, is it better to use *tuple *or *list
*or it just does *not *matter ?

For example (the area_server0 example in "programming erlang"),

-module(area_server0).
-export([loop/0]).

loop() ->
   receive
      *{rectangle, Width, Ht}* -> % tuple here
          io:format("Area of rectangle is ~p~n" ,[Width * Ht]),
          loop();
      {circle, R} ->
          io:format("Area of circle is ~p~n" , [3.14159 * R * R]),
          loop();
      Other ->
          io:format("I don't know what the area of a ~p is ~n" ,[Other]),
          loop()
    end.

Here we uses tuples to send/receive messages, but when I change them to
list, the codes still work.

loop() ->
   receive
      *[rectangle, Width, Ht]* ->
      ... % Still works as long as we agree to use list to send the message.

So I was wondering does this mean either tuple or list is ok or there is
still some difference between them ?

Thanks!

Qiulang
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