Proposal: add fromRight and fromLeft to Data.Either

[Anton Felix Lorenzen]

It has been two weeks now since I wrote my proposal.

First of all, thanks to all for their replies
(and sorry for having started such a big discussion).

Tom has mentioned, that there is (\(Right x)->x).
I didn't consider that (shame on me), but I think it is perfect
as it is short and easy to read.

Also it shows the idea of unwrapping,
something which "either undefined id" lacks.

I think it is a good replacement
and therefore withdraw my proposal.


Meanwhile, it was proposed to include
   fromLeft  :: a -> Either a b -> a
   fromRight :: b -> Either a b -> b
I am a weak +1 on this.

--
Anton

On 05/20/2016 10:08 PM, Anton Felix Lorenzen wrote:
> When working with Either,
> I am often missing two simple functions:
> fromRight :: Either a b -> b
> fromLeft  :: Either a b -> a
>
> It has been implemented a couple of times:
> http://hayoo.fh-wedel.de/?query=fromRight
>
> But I don't want to depend on yet another library
> for such a basic function.
>
> Could it be added?
>
> Anton
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