Re: Proposal: Add `restriction` to Data.Map and Data.IntMap

I'm not sure yet, but I suspect it might be possible to implement partitionByKeySet more efficiently than the naive way. But to do so, it will have to construct both pieces eagerly, meaning that using only part of its result will waste time and allocation. On Mon, Jul 25, 2016 at 3:34 PM, Andreas Abel wrote:

Seems like the partition function would subsume the others?!

partitionByKeys :: Ord k => Set k -> Map k a -> (Map k a, Map k a)

Would there be impressive speed gains for a native

fst . partitionByKeys set

?

On 25.07.2016 20:59, David Feuer wrote:

...

A final question:

Both `restrictKeys` and `withoutKeys` are special cases of `filterWithKey` (although they should be considerably more efficient than implementations using that function). Do we also want a `partition` special case, in which a map is partitioned into the keys that are in a set and the ones that are not?

On Mon, Jul 25, 2016 at 1:10 PM, Edward Kmett wrote:

...

Good enough for me.

On Mon, Jul 25, 2016 at 12:11 PM, David Feuer wrote:

...

I got distracted from this discussion for a bit. Based on input from the list, and Ross Paterson's remark about argument order, I'm currently thinking

restrictKeys :: Ord k => Map k a -> Set k -> Map k a

and

withoutKeys :: Ord k => Map k a -> Set k -> Map k a

Are there any major objections?

On Thu, Jul 14, 2016 at 12:54 PM, Alexey Vagarenko wrote:

...

How about `keepKeys`?

2016-07-14 21:36 GMT+05:00 Daniel Trstenjak :

...

On Thu, Jul 14, 2016 at 12:02:51PM -0400, David Feuer wrote: > > If you name it, it will come!

intersectKeys and differentiateKeys

or

intersectionWithSet and differenceWithSet

or ;)

intersectionOfKeys and differenceOfKeys

Greetings, Daniel _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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-- Andreas Abel <>< Du bist der geliebte Mensch.

Department of Computer Science and Engineering Chalmers and Gothenburg University, Sweden

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