#9586: Implement Traversable/Foldable-Burning-Bridges Proposal -------------------------------------+------------------------------------- Reporter: hvr | Owner: hvr Type: task | Status: new Priority: normal | Milestone: 7.10.1 Component: | Version: libraries/base | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Difficult (2-5 Unknown/Multiple | days) Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: Phab:D209 | -------------------------------------+------------------------------------- Comment (by dfeuer): I think if you're doing this, it would make sense to generalize these too: {{{#!hs null :: (Foldable f) => f a -> Bool null = foldr (const True) False length :: (Foldable f) => f a -> Int length = foldl' (\k _ -> k + 1) 0 --and even though it's a very strange thing already genericLength :: (Foldable f, Num n) => f a -> n genericLength = foldr (\_ k -> 1 + k) 0 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9586#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler