Try to make Set an instance of Functor and you'll see why it isn't.
It's very annoying.
On Mon, Jul 26, 2010 at 11:55 PM, Gregory Crosswhite
wrote:
> Is there a specific reason why Set doesn't have instances for Functor
> and Traversable? Or have they just not been written yet? :-)
>
> Cheers,
On Mon, 26 Jul 2010, Gregory Crosswhite wrote:
Is there a specific reason why Set doesn't have instances for Functor
and Traversable?
Sure, fmap needs an Ord restriction for the element type, which is not
possible for the plain Functor constructor class. E.g. in
fmap (const 'a') set
all
Is there a specific reason why Set doesn't have instances for Functor
and Traversable? Or have they just not been written yet? :-)
Cheers,
Greg
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