[Haskell-beginners] confusing type signature with sections
Karl Voelker
ktvoelker
Wed Oct 2 17:25:23 UTC 2013
On Tue, Oct 1, 2013 at 5:25 PM, Patrick Redmond <plredmond at gmail.com> wrote:
> Prelude> :t ((+ 1) / 2)
> ((+ 1) / 2) :: (Fractional (a -> a), Num a) => a -> a
>
The key is that typeclasses are open. You could write a Fractional instance
for (a -> a), in which case it would be possible to do _something_ with
this code. Would it be useful? Even Haskell can't guarantee that.
-Karl
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