TDataFamily.hs

{-# LANGUAGE TypeFamilies #-}
module TDatafamily where

-- Declare a list-like data family
data family XList a

-- Declare a list-like instance for Char
data instance XList Char = XCons !Char !(XList Char) | XNil

-- Declare a number-like instance for ()
data instance XList () = XListUnit !Int