From: Pavel Perikov <perikov@gmail.com>

Date: 6 мая 2010 г. 11:55:36 Московское летнее время

To: haskell-cafe list Cafe mailing <haskell-cafe@haskell.org>

Cc: Беркгаут Борис <boris.berkgaut@transas.com>

Subject: {-# LANGUAGE DeriveApplicative #-} ?

Hi, list!.

Now in 6.12.1 we have DeriveFunctor, DeriveFoldable and DeriveTraversable. This greatly simplifies the "reuse structure" style of programming. Some structure (not just _data_ structure) got captured in ADT and can be reused for various purposes.

Wouldn't it be nice to have the ability to derive Applicative as well? It shouldn't be more difficult than deriving Functor but will provide exciting possibilities. Just think about liftA2.

Please note that deriving Monad is quite different story and seem generally unfeasible.

Suggestions welcome.

P.