[Haskell-cafe] Established names for a couple of list functionals?
nicolas.pouillard at gmail.com
Wed Apr 7 03:22:41 EDT 2010
On Tue, 6 Apr 2010 21:56:37 +0100, Stephen Tetley <stephen.tetley at gmail.com> wrote:
> Hello all
> Having traversals with special behaviour for the first or last element
> is useful for my current work:
> -- first element special
> anacrusisMap :: (a -> b) -> (a -> b) -> [a] -> [b]
> anacrusisMap _ _  = 
> anacrusisMap f g (a:as) = f a : map g as
I think it makes for sense to not wire in the map function.
firstOthers :: (a -> b) -> ([a] -> [b]) -> [a] -> [b]
firstOthers _ _  = 
firstOthers f g (x:xs) = f x : g xs
Then anacrusisMap is so short that we don't give it a name.
anacrusisMap f = firstOthers f . map
Same thing goes to the other one.
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