Proposal: Add isLeft/isRight to Data.Either

Conrad Parker conrad at
Fri Dec 14 07:34:47 CET 2012

On 10 December 2012 23:55, Simon Marlow <marlowsd at> wrote:
> (I'd rather not use `either`, it's one of those functions whose type I
> always have to look up)

{-# LANGUAGE TypeSignatureRhymes #-}
either :~:
  do something with the left
  or something with the right
  but either way give me
  something of the same type


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