#8: Data.Functor.Class: Wrapper type that resolves e.g. (Eq (f a)) to (Eq1 f, Eq a)

concrete functor and monad transformers

#8Data.Functor.Class: Wrapper type that resolves e.g. (Eq (f a)) to (Eq1 f, Eq a)

newtype Wrap f a = Wrap {unwrap :: f a}

instance (Eq1 f, Eq a) => Eq (Wrap f a) where
   Wrap x == Wrap y  =  eq1 x y

We should also have analogous instances for Ord, Show, Read.

Ryan Scott Tue Aug 18 16:15:08 UTC 2015
This is the same idea as Lift and `Lift2
Ryan Scott Tue Aug 18 16:18:26 UTC 2015
Er, sorry, I accidentally submitted the last comment too early.

This is the same idea as Lift and Lift2 from prelude-extras, correct? (I'm not sure if I like either one of those names, to be honest, but we'd have to name it something.)
Ryan Scott Mon Sep 14 15:27:51 UTC 2015
On second thought, I'd rather not name it Lift, since it might become an important thing soon ( https://ghc.haskell.org/trac/ghc/ticket/1830 ).

In that case, I have no better name suggestions, so let's go with Wrap :)
Ross Paterson Fri Jan 1 10:05:17 UTC 2016
- status set to closed
Eq1 and friends have moved to base in preparation for GHC 8.0
thielema Mon Jan 11 20:16:59 UTC 2016
IdentityT can be used instead.