Reorganized code and types, changed slightly the architecture.

Plugins/Ping.hs

@@ -0,0 +1,22 @@
+module Plugins.Ping
+    ( mainPing
+    ) where
+
+import Control.Concurrent.Chan
+
+import Hsbot.Types
+
+mainPing :: Chan BotMsg -> Chan BotMsg -> IO ()
+mainPing serverChan chan = do
+    loop
+    where
+        loop = do
+            input <- readChan chan
+            eval input
+            loop
+        eval :: BotMsg -> IO ()
+        eval (InputMsg msg)
+            | (command msg) == "PING" = writeChan serverChan $ OutputMsg $ IrcMsg Nothing "PONG" (parameters msg)
+            | otherwise = return ()
+        eval _ = return ()
+