As a tangent I am interested in knowing what would be the typeclass for this sort of operation:
- take all the elements out of `f a` - do something with them with a function a -> b - insert the results back to get the same "original shape" `f b`
In this case "do something with them" is "order them" but it could also be "invoke a function with all the 'a's and dispatch back the results" to allow "batching" function calls.
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Eric TORREBORRE
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Le mardi 17 octobre 2017 à 11:05:43 UTC+2, Henning Thielemann
I would imagine
ordNub :: (Foldable t, Ord a) => t a -> [a]
The kind of generalization where the input is Foldable but the output is just a list looks pretty unnatural to me. I think it means that we still do not have the proper generalization that allows us to define ordNub :: (??? f, Ord a) => f a -> f a I would just leave it as ordNub :: (Ord a) => [a] -> [a]_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries