Diagonalization/ dupe for monads and tuples?

[Oliver Charles]

You may wish to compare with fromMaybe then, which probably also doesn't have the type you'd expect :) The type you have there is more like bifoldMap

On Thu, 17 Sep 2020, at 1:42 PM, Carter Schonwald wrote:
> I’d expect fromEither to be 
> Either a b -> (a-> c )-> (b-> c) -> c 
> 
> Nothing about the name fromEither is suggestive of the Either a a type 
> 
> On Thu, Sep 17, 2020 at 3:45 AM Oliver Charles <ollie at ocharles.org.uk> wrote:
>> __
>> Regardless of having a more abstract version, I'm +1 on Jon's suggestion, and those names. fromEither is something I have reached for many many times and been surprised it's not within arms reach.
>> 
>> On Thu, 17 Sep 2020, at 7:16 AM, Jon Purdy wrote:
>>> I’m strongly for these:
>>> 
>>> Data.Tuple.dup :: a → (a, a)
>>> 
>>> Data.Either.fromEither :: Either a a → a
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