[Haskell-cafe] Newbie question about tuples
lemming at henning-thielemann.de
Thu Jul 12 15:24:24 EDT 2007
On Thu, 12 Jul 2007, Andrew Coppin wrote:
> peterv wrote:
> > Q3) Suppose I want to declare an instance of Num on all tuple types having
> > (Num instances) as elements; is this possible?
> > I tried
> > instance Num a => Num (a,a) where .
> > but this fails
> > I also tried
> > instance Num a => Num ((,) a a) where .
> > but that also fails.
> I tried to do this a while ago and couldn't figure out how. :-(
The new approach of peterv using
data Vector2 a = Vector2 a a
is more sane.
More information about the Haskell-Cafe