#12828: Generalize functions from Data.Maybe (‘catMaybes’, ‘mapMaybe’) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: lowest | Milestone: Component: Core | Version: 8.0.1 Libraries | 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: -------------------------------------+------------------------------------- Opening a ticket for discussion. As mentioned in [https://www.reddit.com/r/haskell/comments/2y2pe5/shouldnt_ftp_propagate_chan... this comment], more functions can be generalized to `Foldable` {{{#!hs catMaybes :: Foldable f => f (Maybe a) -> [a] mapMaybe :: Foldable f => (a -> Maybe b) -> (f a -> [b]) listToMaybe :: Foldable f => f a -> Maybe a }}} I think `catMaybes` and `mapMaybe` are fine candidates. The comment offers more extreme changes, {{{#!hs catMaybes :: (Foldable f, Foldable g) => Foldable f => f (g a) -> [a] mapMaybes :: (Foldable f, Foldable g) => (a -> f b) -> (f a -> [b]) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12828 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler