gistfile1.hrl

-module('area').
-export([start/0,area/2]).

start() -> spawn(fun loop/0).

area(Pid,What) -> rpc(Pid,What).

rpc(Pid,Request) ->
  Pid ! {self(),Request},
  receive
    {Pid,Response} -> Response
  end.

loop() ->
  receive
    {From,{rectangle,Width,Ht}} ->
      From ! {self(),Width*Ht},
      loop();
    {From,{circle,R}} ->
      From ! {self(),3.14159 * R * R},
      loop();
    {From,Other} ->
      From ! {self(),Other},
      loop()
  end.