#13026: RFC functions for sums and products -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: libraries/base | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Please consider these functions from a [http://stackoverflow.com/a/25817530/165806 StackOverflow answer] {{{#!hs liftO :: (Functor f, Applicative g) => f ~> Compose f g liftO = Compose . fmap pure liftI :: Applicative f => g ~> Compose f g liftI = Compose . pure hoistO :: f ~> f' -> Compose f g ~> Compose f' g hoistO eta = Compose . eta . getCompose hoistI :: Functor f => g ~> g' -> Compose f g ~> Compose f g' hoistI eta = Compose . fmap eta . getCompose }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13026#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler