Re: Adding swap/compose functions to Data.Tuple and Data.Function

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Edward Kmett writes:

Data.Tuple already contains swap.

Yeah, and I'm finding it just fine with Hoogle now. I'm not sure how I was led into thinking it didn't exist, but I had reached for it one day and my hands came up empty.

    compose :: [(a -> a)] -> a -> a     compose = foldr (.) id

    composeM :: [(a -> m a)] -> a -> m a     composeM = foldr (<=<) return

The composition of them is obvious, and the suggested names already exist commonly in a lot of third party code for all sorts of purposes.

The pain of adoption plus the annoyance of trying to find them exceeds, to me, the utility of adding them.

Fair enough. It does seem that the idiom deserves a name, though, considering how often I've come across it, but perhaps that ship has sailed. -- John Wiegley FP Complete Haskell tools, training and consulting http://fpcomplete.com johnw on #haskell/irc.freenode.net