Support `MonadError`?

[michaelpj]

Just found this library, it looks very nice!

However, I mostly just use MonadError in my code, not MonadThrow. It would be great to have similar functionality for MonadError, although I don't know how hard that would be.

[mtesseract]

Hi,

interesting point. I was really only focusing on MonadThrow and MonadCatch when I wrote this.
Maybe we can in fact come up with an implementation for MonadError, supporting similar but (most likely) different semantics.

Right now I don't have much time for analyzing this situation, though.