[Haskell-cafe] Alternative IO

Wolfgang Jeltsch g9ks157k at acme.softbase.org
Fri Jul 17 10:23:30 EDT 2009


Am Samstag, 11. Juli 2009 00:16 schrieben Sie:
> On Friday 10 July 2009 4:35:15 am Wolfgang Jeltsch wrote:
> > I fear that this instance doesn’t satisfy required laws. As far as I
> > know, the following equalities should hold:
> >
> >     (*>) = (>>)
> >
> >     f *> empty = empty
>
> IO already fails at this law, because (f *> empty) is not the same as
> empty,

Huh? There was no Applicative instance for IO. This was the reason for 
Cristiano to define one, and my mail pointed out a problem in his definition.

Best wishes,
Wolfgang


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