Re: [boost] [geometry] view_as concept casting

Subject: Re: [boost] [geometry] view_as concept casting
From: David Abrahams (dave_at_[hidden])
Date: 2009-01-09 20:32:09

on Fri Jan 09 2009, "Simonson, Lucanus J" <lucanus.j.simonson-AT-intel.com> wrote:

> I think it was gcc 3.4.2, but it might have been gcc 3.2.2.  I don't clearly remember.
> I pretty much stopped worrying about it when I found that it isn't a problem with
> current compilers and I was no longer planning to do it anyhow.  No need for bug
> report.
>
>>That's in boost/type_traits/is_convertible.hpp; I didn't have to
>>implement it!
>
> Nice.  Good to know.  How does it work?

Use the source, Luke.

>>If you use SFINAE in the traditional way, you can't take advantage of
>>any refinement relationships and you need to explicitly exclude all the
>>other cases.  Of course, you could use SFINAE with an is_convertible
>>test on the tags, which would get around that problem.  But I would
>>still do that on the dispatch function and use tags to select the
>>implementation.
>
> Yes, saves some typing of SFINAE meta-logic.

Not just typing; also coupling and maintenance nightmares.

Cheers,

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com