Haskell: The Craft of Functional Programming
	Simon Thompson
	(c) Addison-Wesley, 1999.

	The basis of the simulation package.

>	module Base where


The type of input messages. 

>	data Inmess = No | Yes Arrival Service
>		      deriving (Eq,Show)

>	type Arrival = Int
>	type Service = Int

The type of output messages. 

>	data Outmess = None | Discharge Arrival Wait Service
>		       deriving (Eq,Show)

>	type Wait = Int