Haskell' - class aliases

Wolfgang Jeltsch g9ks157k at acme.softbase.org
Thu Apr 24 14:48:15 EDT 2008


Am Mittwoch, 23. April 2008 06:18 schrieb John Meacham:
> On Tue, Apr 22, 2008 at 08:33:53AM +0100, Simon Peyton-Jones wrote:
> > Is this the most up-to-date description of the proposal?
> >         http://repetae.net/recent/out/classalias.html
>
> There were a few changes proposed in the discussion that followed my
> announcement that I wanted to make. The one I can remember now is
> getting rid of the 'alias' keyword since the equals sign unabiguously
> identifies it as an alias. I will dig through the archive to find the
> others..

I also have some remark: Why not write

> class Eq a => Num a = (Additive a, Multiplicative a)

instead of

> class Num a = Eq a => (Additive a, Multiplicative a)

The former would better match the syntax for ordinary class declarations like:

> class Eq a => Num a where
>
>     […]

> […]

Best wishes,
Wolfgang


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