{-# LANGUAGE TypeFamilies #-} module Types where data Quux = Bar | Baz newtype Foo = Foo () type FooQuux = (Foo, Quux) type QuuxFoo = (Quux, Foo) data family Norf a b data instance Norf Foo Quux = NFQ Foo Quux data instance Norf Quux Foo = NQF Quux Foo type family Norf' a b type instance Norf' Foo Quux = (Foo, Quux) type instance Norf' Quux Foo = (Quux, Foo) norf1 :: Norf Foo Quux -> Int norf1 :: Norf Foo Quux -> Int norf1 (NFQ (Foo ()) Bar) = Int 0 norf1 (NFQ (Foo ()) Baz) = Int 1 norf2 :: Norf Quux Foo -> Int norf2 :: Norf Quux Foo -> Int norf2 (NQF Bar (Foo ())) = Int 0 norf2 (NQF Baz (Foo ())) = Int 1 norf1' :: Norf' Foo Quux -> Int norf1' :: Norf' Foo Quux -> Int norf1' (Foo (), Bar) = Int 0 norf1' (Foo (), Baz) = Int 1 norf2' :: Norf' Quux Foo -> Int norf2' :: Norf' Quux Foo -> Int norf2' (Bar, Foo ()) = Int 0 norf2' (Baz, Foo ()) = Int 1