On Mon, May 30, 2011 at 6:26 PM, Gordon Woodhull <gordon@woodhull.com> wrote:
A system of objects at compile time is a graph of types and their relations.  Where I am hoping concepts will help is to be able to define abstractly what sort of interfaces exist between these types, and then validate that the concrete implementation meets the concepts.

Can you give an example of what kind of interface requirements you'd have? I'm imagining that you mean some kind of required metafunctions that are associated with the types, in which case I'm pretty sure that all you'd need past what I currently have implemented are associated templates, but I want to make sure we really are on the same page. 
 
So, I think this requires carrying concepts as metadata in the edges of a compile-time graph specified by the Metagraph user, and then traversing both the abstract and the concrete graphs validating the types against the concepts they are supposed to implement.

That would not be possible, at least in terms of the 0x proposed concepts, though given your earlier description I'm not entirely convinced that you actually need such functionality to accomplish what you want.

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-Matt Calabrese