[Haskell-cafe] What is MonadPlus good for?

Remi Turk rturk at science.uva.nl
Sat Feb 12 14:10:03 EST 2005

On Sat, Feb 12, 2005 at 01:47:06PM -0500, Benjamin Pierce wrote:
> > As a start, free access to countless general functions as soon as
> > you define a MonadPlus instance for your datatype. (Errr, `guard'
> > and `msum', as long as one stays within the Haskell98 standard
> > libraries ;)
> Yes, those are good examples.  (But I'd still be interested to see some of
> the countless others... :-)
> Thanks,
>     - Benjamin

Network.URI and Data.Generics also define a few functions
which require MonadPlus instances. Can't find anything else right
now. Nor do I know of the (countless? ;)) more theoretical
reasons to define instances.

Nobody can be exactly like me. Even I have trouble doing it.

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