[Haskell-cafe] Re: what is inverse of mzero and return?

[Ashley Yakeley]

In article <200501231755.45127.jadrian at mat.uc.pt>,
 Jorge Adriano Aires <jadrian at mat.uc.pt> wrote:

> I just checked the paper,
> "A monadic Interpretation of Tatics", by Andrew Martin and Jeremy Gibbons
> http://web.comlab.ox.ac.uk/oucl/work/jeremy.gibbons/publications/tactics.pdf
> 
> And in deed, these are the listed laws for MonadPlus. On the other hand, 
> Maybe 
> is said to be an instance of MonadPlus.
> 
> So now I'm lost. 

OK, Martin and Gibbons are to blame, then. I like their list or laws, 
but they're wrong to say that Maybe satisfies those laws.

-- 
Ashley Yakeley, Seattle WA