Re: The new Boost 17.0.0

From: Gavin Lambert (boost_at_[hidden])
Date: 2020-11-30 01:32:08

On 30/11/2020 1:36 pm, Peter Dimov wrote:
> Gavin Lambert wrote:
>> > For this specific use, it doesn't need to. It can just match against 
>> a > StringLike concept, as I said.
>>
>> Except that you can't use concepts in a compiled library, only in a 
>> header-only one.  (Or it still requires you to write that concrete 
>> type conversion.)
> 
> Of course you can.
> 
> class string_view
> {
> public:
> 
>  Â Â  template<class StringLike,
>  Â Â Â Â Â Â  class E = enable_if_t<is_string_like<StringLike>>
>  Â Â  >
>  Â Â  string_view( StringLike const& sl ): p_( sl.data() ), n_( sl.size() 
> ) {}
> };
> 
> void my_compiled_library( string_view sv );

Yes, that's exactly what I meant by "concrete type conversion".

Since the standard library string_view doesn't (currently?) do this, it 
means that everybody will be writing their own string_views.  (Or worse: 
writing their own is_string_like.)  This is not an improvement.

> Victor Zverovich has independently come to the same conclusion:
 > https://twitter.com/vzverovich/status/1333111364357746690

I'm not sure if that was the wrong link or if you're referring to 
something non-obvious to me there, but that doesn't appear related.