C++0x Concepts - Dead?

[aarti_pl]

Jarrett Billingsley pisze:
> Please, the last thing we need is to have *two* systems of template
> specialization, one with best matching and one without.
> 
> I was thinking it'd be more intuitive if constraints - which are more
> general - would be used to implement specialization.  That is,
> 
> template X(T: A, U: B)
> 
> would basically be syntactic sugar for
> 
> template X(T) if(is(T: A) && is(U: B))
> 
> Then you have only a single system of specialization and constraining
> to worry about.  How would "best matching" work?  The compiler could
> definitely be smart enough to pick apart the logical expression in the
> constraint, I suppose, or constraints could be written as "if(c1, c2,
> c3)" or something of the like.
> 
> Let's try to *simplify* metaprogramming and make things *orthogonal*
> instead of tacking on features with no regard to the existing ones.

Well, that's exactly what I proposed about one year ago:

http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=77654

My proposal would make meta programing in D much more intuitive (because 
of using rules - not bunch of corner cases as it is today). 
Unfortunately almost no one from NG commented on that...

BR
Marcin Kuszczak
(aarti_pl)