intersectionSet, differenceSet

[Andreas Abel]

Sounds ok, by why especially for Set.  Why not (also)

     Map.intersectionList :: Ord k => Map k a -> [k] -> Map k a
     Map.differenceList :: Ord k => Map k a -> [k] -> Map k a

? Screams for a generalization.

On 15.11.12 11:34 AM, Henning Thielemann wrote:
>
> When using the new Data.Map.fromSet function I encountered that I use it
> many times in connection with Map.intersection and Map.difference like so
>
>    Map.intersection m (Map.fromSet (const ()) s)
>    Map.difference m (Map.fromSet (const ()) s)
>
> Actually the element types of the second operands of Map.intersection
> and Map.difference are completely independent and the values of these
> maps are not touched. Thus I think that intersection and difference with
> a Set are the more natural operation. How about adding
>
>    Map.intersectionSet :: Ord k => Map k a -> Set k -> Map k a
>    Map.differenceSet :: Ord k => Map k a -> Set k -> Map k a
>
> to Data.Map?
>
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-- 
Andreas Abel  <><      Du bist der geliebte Mensch.

Theoretical Computer Science, University of Munich
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