#13593: Unexpected behavior from Data.List.groupBy -------------------------------------+------------------------------------- Reporter: dsf | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dsf): To be fair, the documentation says "supply your own equality function", and what I'm supplying above is not an equality function. But a better interface might be something like {{{#!hs groupOn :: Eq b => (a -> b) -> [a] -> [[a]] groupOn f xs = groupBy ((==) `on` f) xs }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13593#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler