I wouldn't want to encourage partial functions without even an error message.  Usually with Either you'll want to use the unexpected value in the error msg, e.g 'either (error . ("xyz: "++) . show) id'.

On Fri, May 20, 2016 at 1:08 PM, Anton Felix Lorenzen <anfelor@posteo.de> 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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