31 Oct
2007
31 Oct
'07
9:38 a.m.
On Wed, 2007-10-31 at 14:29 +0100, Thomas Schilling wrote:
Hi there.
I recently find myself missing Data.Set.mapMaybe. This function is implemented for Data.Map.Map, but is strangely missing from Data.Set.mapMaybe. I believe it could be implemented using Data.Foldable, but not as efficiently. The obvious implementation would be:
mapMaybe :: (Ord a, Ord b) => (a -> Maybe b) -> Set a -> Set b mapMaybe f Tip = Tip mapMaybe f (Bin _ x l r) = case f x of Nothing -> merge (mapMaybe f l) (mapMaybe f r) Just y -> union y (mapMaybe f l) (mapMaybe f r)
Any comments?
D'oh! This is wrong. Sorry, for the noise.