#13026: RFC functions for sums and products -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: | Version: 8.0.1 libraries/base | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I'll ask on the libraries mailing list depending on feedback. Adding these to `Data.Functor.Sum`, `Data.Functor.Product` a la `Control.Arrow` {{{!hs (||||) :: (f a -> b) -> (g a -> b) -> ((Sum f g) a -> b) f |||| g = \case InL fa -> f fa InR ga -> g ga (&&&&) :: (a -> f b) -> (a -> g b) -> (a -> (Product f g) b) (f &&&& g) a = f a `Pair` g a }}} `||||` is used in "Monad transformers and modular algebraic effects: What binds them together" in section 2.4, the names are up for discussion -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13026 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler