[Haskell-cafe] MonadPlus instance for IO

Daniel Fischer daniel.is.fischer at web.de
Wed Feb 2 10:38:14 EST 2005

Am Mittwoch, 2. Februar 2005 14:48 schrieb David Roundy:
> On Wed, Feb 02, 2005 at 02:41:42PM +0100, Daniel Fischer wrote:
> > Probably you haven't imported 'Control.Monad.Error', where the instance
> > is defined. I did and all went well.
> Thanks, that did it.  It's confusing that the instance is documented in
> Control.Monad.

Yes, very confusing, but what could one do?
Maybe urge people to mention instance declarations in the module description,
so from the absence of one, you are led to look elsewhere.
But that might make descriptions unduly large sometimes.


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