10 Feb
2006
10 Feb
'06
12:11 p.m.
On Fri, Feb 10, 2006 at 05:20:47PM +0100, Niklas Broberg wrote:
- when looking at the definition of MonadWriter the Monoid constraint is not strictly necessary, and none of the other mtl monads have anything similar. Is it the assumption that this kind of constraint is never really necessary, and thus no support for it is needed for ATS?
I think that's right -- it's only needed for the Monad instance for WriterT. But it is a convenience. In any instance of MonadWriter, the w will be a monoid, as there'll be a WriterT in the stack somewhere, so the Monoid constraint just saves people writing general functions with MonadWriter from having to add it.