{-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE OverlappingInstances #-} {-# OPTIONS -fno-warn-orphans #-} ----------------------------------------------------------------------------- -- | -- Module : Generics.EMGM.Data.Bool -- Copyright : (c) 2008 Universiteit Utrecht -- License : BSD3 -- -- Maintainer : generics@haskell.org -- Stability : experimental -- Portability : non-portable -- -- Summary: Generic representation and instances for 'Bool'. -- -- This module exports the reusable components of the 'Bool' -- representation. These include the embedding-projection pair used in a type -- representation as well as the type representation of 'Bool' for -- 'Generic'. -- -- This module also exports the instance for the representation dispatcher -- 'Rep'. ----------------------------------------------------------------------------- module Generics.EMGM.Data.Bool ( -- * Embedding-projection pair epBool, -- * Representation rBool, ) where import Generics.EMGM.Common ----------------------------------------------------------------------------- -- Embedding-projection pair ----------------------------------------------------------------------------- fromBool :: Bool -> Unit :+: Unit fromBool False = L Unit fromBool True = R Unit toBool :: Unit :+: Unit -> Bool toBool (L Unit) = False toBool (R Unit) = True -- | Embedding-projection pair for @Bool@ epBool :: EP Bool (Unit :+: Unit) epBool = EP fromBool toBool ----------------------------------------------------------------------------- -- Representation values ----------------------------------------------------------------------------- conFalse, conTrue :: ConDescr conFalse = ConDescr "False" 0 [] Nonfix conTrue = ConDescr "True" 0 [] Nonfix -- | Representation for @Bool@ in 'Generic' rBool :: (Generic g) => g Bool rBool = rtype epBool (rcon conFalse runit `rsum` rcon conTrue runit) ----------------------------------------------------------------------------- -- Instance declarations ----------------------------------------------------------------------------- instance (Generic g) => Rep g Bool where rep = rBool