Anyone but the newest beginner who needs the functionality of unions
or (for Data.Map) unionsWith should be able to write it themselves
with barely a second thought, using foldl'. The newest beginner might
find this a good opportunity to learn about foldl'. In my personal
opinion, the bar is set by Data.Sequence.intersperse; users *could*
write their own efficient version, but I don't expect a user to
necessarily come up with
intersperse :: a -> Seq a -> Seq a
intersperse y xs = case viewl xs of
EmptyL -> empty
p :< ps -> p <| (ps <**> (const y <| singleton id))
at the drop of a hat.
On Sun, Feb 4, 2018 at 3:17 PM, Henning Thielemann
On Sun, 4 Feb 2018, Joachim Breitner wrote:
Hi,
Am Samstag, den 03.02.2018, 20:44 -0500 schrieb David Feuer:
It is fold, although fold is not so great for lists in this context. It's also foldl' union Set.empty, which is better for lists, and probably also for balanced trees. I initially thought that we should surely generalize, but now another alternative comes to mind: remove. As a containers maintainer, I believe we should either:
1. Generalize as proposed, or 2. Deprecate and remove.
I'm currently somewhat in favor of the second option.
please don’t remove!
…is first reaction. Now I just have to rationalize my gut feeling…
I like the readability of it in code, it is more descriptive.
Right.
As always, I see no sense in only preserving a most general version of a function. Code that consists of nested fold, fmap, (<>) is practically unreadable. Only use that if you really want generic code. _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries