Hi guys!

I'd like to implement the instance in the subject:
instance Alternative (Either [a])

However the instance in Control.Monad.Trans.Error.Error gets in the way...

I cannot use this one, it works only with Strings.

My use case is that the Either handle in the Right a final value, or else in the Left a list of things "left to do" to compute the value.

How can I do?

Thanks!

Corentin