Re: Haskell Foldable Wast

I think the ship has sailed on big breaking changes to Foldable/Traversable -- an argument could be made to remove a wonky instance, but removing Foldable as a superclass seems to me like a much bigger change. Tom

El 21 feb 2016, a las 07:57, Jeremy escribió:

Marcin Mrotek wrote

...

I think that, as far as Foldable is concerned, a tuple is equivalent to Identity, so this instance is indeed useless. However, Foldable is a superclass of Traversable (and it wouldn't make much sense to make these classes unrelated, as one can always define folds with `traverse`), so I've always found it a necessary evil.

Perhaps the case of tuple is evidence that Foldable should *not* be a superclass of Traversable?

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