Re: [boost] [geometry] view_as concept casting

Subject: Re: [boost] [geometry] view_as concept casting
From: Barend Gehrels (barend_at_[hidden])
Date: 2009-01-08 17:24:13

Hi Luke,

Simonson, Lucanus J wrote:
> Barend wrote:
>   
>> Furthermore, you mention:  "concept checking boilerplate around bool
>> return type goes here". We've encountered problems with the concept
>> checking on return types. The combination of BCCL and overloads based on
>> SFINAE gives compiler problems here. We therefore use
>> BOOST_CONCEPT_REQUIRES instead of _ASSERT in such cases.
>>     
>
> What compiler problems specifically?
> I don't use BCCL for concept checking, and should have said SFINAE meta-programming boilerplate instead.
>   
Compiler problems: that it fails to specializes the function as soon as 
the BCCL check is there. That is related to the SFINAE overloads. Cannot 
reproduce it literally and it was also compiler dependant. But if the 
BOOST*ASSERT was removed they were gone. It might also be solved by 
using tag dispatchment suggested by Dave, I'll look to that.

Regards, Barend