MonadError and fundeps

Andrew J Bromage
Fri, 11 May 2001 14:40:27 +1000

G'day all.

On Thu, May 10, 2001 at 09:24:36PM +0000, Marcin 'Qrczak' Kowalczyk wrote:

> BTW, another question: should MonadPlus instead of just Monad be
> a superclass of MonadError? It has a natural definition in terms
> of catchError.

I can see how mplus has a "natural" definition (I can think of one or
two circumstances where it's not semantically "natural", even if it is
operationally "natural", but that's beside the point).

What about mzero, though?  What "natural definition" did you have
in mind?

Andrew Bromage