MaybeT to transformers

[Henning Thielemann]

On Fri, 6 Feb 2009, Sittampalam, Ganesh wrote:

> I tend to agree that this is the right one to use, but I think care
> should be taken when adding this to what is/is expected to be a widely
> used package, as it could make it difficult for people who want the
> alternate behaviour, and it might imply a degree of standardisation/
> canonicity that is not really justified.
>
> On the other hand, perhaps there are no real uses for the other one.

I guess the other one is simply
   liftM2 mplus
  on (m (Maybe a)) and thus there would not be much advantage of using 
(MaybeT m) instead of (m (Maybe a)).