Re: [Haskell-cafe] Does somebody know about these functions?

Am 28.02.2012 um 20:21 schrieb Johan Holmquist:

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inter :: (a -> a -> b) -> [a] -> [b] inter f [] = [] inter f l = map (uncurry f) $ zip l (tail l)

This is the same as

inter :: (a -> a -> b) -> [a] -> [b] inter f l = zipWith f l (tail l)

Except when l == [], but the second equation can be replaced by this nicer one.

Even then. :) (zipWith f l (tail l)) first tries to match l with pattern (a:as), and if that fails it will not touch its other argument (tail l).