> module Foreign.Erlang.OTP.GenServer (
>   -- * High-level communication.
>     genCall
>   , genCast
>   , rpcCall
>   , rpcCast
>   ) where

> import Foreign.Erlang.Types      (Erlang, ErlType(..))
> import Foreign.Erlang.Processes

> -- | gen_server:cast(Pid, Msg)

> genCast :: Erlang a => MBox -> Node -> Pid -> a -> IO ()
> genCast mbox node pid msg = mboxSend mbox node pid (ErlAtom "$gen_cast", msg)

> -- | gen_server:call(Pid, Msg)

> genCall :: Erlang a => MBox -> Node -> Pid -> a -> IO ErlType
> genCall mbox node pid msg = do
>     ref <- mboxRef mbox
>     mboxSend mbox node pid (ErlAtom "$gen_call", (mboxSelf mbox, ref), msg)
>     mboxRecv' mbox ref

> -- | rpc:cast(Node, Module, Function, Arguments)

> rpcCast :: MBox -> Node -> String -> String -> [ErlType] -> IO ()
> rpcCast mbox node m f as = genCast mbox node (Right "rex") $
>     (ErlAtom "cast", ErlAtom m, ErlAtom f, as, mboxSelf mbox)

> -- | rpc:call(Node, Module, Function, Arguments)

> rpcCall :: MBox -> Node -> String -> String -> [ErlType] -> IO ErlType
> rpcCall mbox node m f as = genCall mbox node (Right "rex") $
>     (ErlAtom "call", ErlAtom m, ErlAtom f, as, mboxSelf mbox)