Types.lhs

	Types for the calculator

	(c) Simon Thompson, 1998.

>	module Types where

>	data Expr = Lit Int | Var Var | Op Ops Expr Expr	deriving (Eq,Show)

>	data Ops  = Add | Sub | Mul | Div | Mod	 		deriving (Eq,Show)

>	type Var  = Char				

>	data Command = Eval Expr | Assign Var Expr | Null	deriving (Eq,Show)