Sun, 28 Jul 2002 14:44:10 +0200
Hal Daume III wrote:
> As long as we're on the "retrofit FiniteMap" discussion, in addition to
> splitting, etc, it would be really nice to have:
> composeFM :: Ord a, Ord b => FiniteMap a b -> FiniteMap b c
> -> FiniteMap a c
> defined in the obvious way.
> Also, something like:
> modifyFM :: Ord a => FiniteMap a b -> a -> (b -> b) -> FiniteMap ab
> where the function is applied to element a in the fm if it exists.
I agree and further propose
delSetFromFM :: Ord key => FiniteMap key elt -> Set key -> FiniteMap
minusFM :: Ord key => FiniteMap key elt1 -> FiniteMap key elt2
-> FiniteMap key elt1
because elements in the second map are ignored anyway!