Data.Monoid.First and Data.Monoid.Last

Sterling Clover s.clover at
Sun Jan 9 21:50:31 CET 2011

On Jan 9, 2011, at 3:34 PM, Louis Wasserman wrote:

> Is there a reason that Data.Monoid.First and Data.Monoid.Last aren't also instances of Functor, Applicative, Alternative, Monad, MonadPlus?  I find those instances quite useful.

Funny you should mention that. I have a current proposal (deadline Jan 20) to add those instances:


The proposal didn't deal with Alternative and MonadPlus, but now that it's been pointed out (twice) I absolutely agree that they should be added as well.


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