intersections [] = empty is unacceptable to me. The options that make sense
to me are the nonempty (ideally Foldable1) one, one producing a Maybe, and
I guess even one that throws an error on an empty list (ouch).
On Sun, Dec 6, 2020, 1:50 PM Sven Panne
Am So., 6. Dez. 2020 um 07:20 Uhr schrieb Reed Mullanix < reedmullanix@gmail.com>:
[...] intersections :: Ord a => NonEmpty (Set a) -> Set a intersections (s :| ss) = Foldable.foldl' intersection s ss [...]
Why NonEmpty? I would expect "intersections [] = Set.empty", because the result contains all the elements which are in all sets, i.e. none. That's at least my intuition, is there some law which this would violate? _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries