AccValidation has an Applicative instance that accumulates on "Left" (Failure) as per the previous email. Therefore, it has no Monad.

Validation has a Monad and Applicative the same as Either.

On Thu, May 22, 2014 at 2:18 PM, Kim-Ee Yeoh <ky3@atamo.com> wrote:

On Thu, May 22, 2014 at 6:58 AM, Tony Morris <tmorris@tmorris.net> wrote:

http://hackage.haskell.org/package/validation-0.3.4/docs/Data-Validation.html

I don't understand how to use this package.

Is it because Either is an ugly name for the data type and Validation is preferable?

And AccValidation is to be used over Validation, like in Hungarian notation, to indicate (the possibility of?) a Semigroup instance on Left / Failure?

-- Kim-Ee