Re: [boost] Yet another concept checker

From: Chad Parry (spam_at_[hidden])
Date: 2006-08-22 13:46:39

"Douglas Gregor" <doug.gregor_at_[hidden]> wrote in message 
news:ECF14E7B-BC49-4021-9828-A1EF57C862E9_at_cs.indiana.edu...
>
> On Aug 20, 2006, at 11:48 PM, David Abrahams wrote:
[snip]
>> Well, it looks really interesting (really!), but I think you should
>> review the ConceptC++ publications, in particular N1849, before
>> investing more time in it.  Also, IMO, you should try to model the
>> standard concepts and see how it works out in practice.
>
> I strongly suggest that we focus on the latest concept proposal,
> N2042. N2042 is the result of countless hours of discussions among
> the authors of the two different concepts proposals, and it is the
> only concepts proposal that will be moving forward.
>
> You can find up-to-date information on the concepts proposals,
> compiler, etc. on the ConceptC++ home page:
>
> http://www.generic-programming.org/languages/conceptcpp/
>

That's exactly the kind of feedback I was hoping for.  I'll focus more of my 
attention on these items you brought up:
1) Try to mimic the declarative syntax rather than the use pattern syntax. 
(There's probably no reason why both can't be supported simultaneously in a 
library solution like this.)
2) Require authors to declare that their types model a concept; don't assume 
matches based on syntax.  Allow for concepts to be declared with the 
opposite default behavior if they wish.
3) Try to make the errors user-friendly.
4) Add support for associated types.  (I've already thought a lot about this 
and it won't be too hard.)
5) Improve the user experience for signatures that are known to be 
undetectable by library code.  This includes the DefaultConstructible<T> 
concept, for example.  I've already thought a little about this.  I know how 
to elegantly encode requirements like Swappable<T, U> but I'll save that for 
another post. :)

Thanks for the encouragement!  I'll report again when I have made some 
progress.  In the meantime, anyone who replies to me privately is welcome to 
have access to the sources.

-- chad