1 files changed, 7 insertions, 1 deletions

diff --git a/src/Network/DatagramServer/Types.hs b/src/Network/DatagramServer/Types.hs
index fea3d503..37fc40db 100644
--- a/src/Network/DatagramServer/Types.hs
+++ b/src/Network/DatagramServer/Types.hs
@@ -73,11 +73,14 @@ instance Address IP where
 
 
 
-type MessageClass msg = MessageClassG (QueryMethod msg) (TransactionID msg)
 
 newtype ReflectedIP = ReflectedIP SockAddr
   deriving (Eq, Ord, Show)
 
+-- The MessageClass/MessageClassG duality is merely a way to help GHC derive
+-- instances without having to cope with the QueryMethod and TransactionID type
+-- functions
+type MessageClass msg = MessageClassG (QueryMethod msg) (TransactionID msg)
 data MessageClassG meth tid = Query meth
                             | Response (Maybe ReflectedIP)
                             | Error (KError tid)
@@ -106,6 +109,9 @@ class Envelope envelope where
     -- Returns: response message envelope
     buildReply :: NodeId envelope -> SockAddr -> envelope a -> b -> envelope b
 
+    -- This is a abstract constructor and a design wart.  Since it returns into
+    -- the IO monad, it allows for outside state to be used in creating
+    -- envelopes.
     buildQuery :: NodeId envelope -> SockAddr -> QueryMethod envelope -> TransactionID envelope -> a -> IO (envelope a)
 
     uniqueTransactionId :: Int -> IO (TransactionID envelope)