[Haskell-cafe] Functional dependencies *not* part of the next Haskell standard?

[Donald Bruce Stewart]

jules:
> peterv wrote:
> >>instance Vector Vector2 where
> >>  dot (V2 x1 y1) (V2 x2 y2) = x1 * x2 + y1 * y2
> >
> >Amazing, so simple it is, Yoda would say ;)
> >
> >I did not realize one could perform "partial application" on types when
> >declaring instances (I mean not specifying the type of Vector2 in <instance
> >Vector Vector2>).
> >
> >Now regarding these funcdeps, are they "ill" as the "rumor" goes?
> 
> I don't think there is any danger of them being removed and not 
> replaced. The functionality is useful.
> 
> Associated Types is widely viewed as a successor/replacement, but no 
> complete implementation exists yet:
> 
> http://haskell.org/haskellwiki/GHC/Indexed_types

I think the implementation is some 90% complete though, in GHC head.
Certainly you can write many associated types programs already -- the
missing part is finishing off associated type synonyms, iirc.

-- Don