Re: [boost] Review Request: impl_ptr (pimpl)

Subject: Re: [boost] Review Request: impl_ptr (pimpl)
From: Vladimir Batov (Vladimir.Batov_at_[hidden])
Date: 2017-08-22 21:37:55

On 08/23/2017 07:07 AM, Seth via Boost wrote:
> On 21-08-17 11:48, Vladimir Batov via Boost wrote:
>> That's ugly and wrong.
> /I'm just gonna say it's neither ugly nor wrong./

OK, OK. :-) We certainly won't be arguing that. :-) I just thought that 
the words themselves clearly indicated that it was in my view, by my 
taste. I do not feel comfortable seeing the code that looks like the 
user introduces something, fiddles in the boost (or std) namespace. I 
have a feeling I might be not the only one feeling that way. :-)

> On 22-08-17 09:50, Gevorg Voskanyan via Boost wrote:
>> so for a long time now, we have a precedent too.

Gevorg was certainly correct pointing out this boost::assertion_failed() 
precedent... Something I have in my code. :-)

> One of a great many.
>
> Same for specializations of std::hash, boost::hash,
> boost::fusion::extension::*, boost::spirit::traits::*, etc.
>
> That said, I'm not convinced there isn't a "better" way: why not
> implement another layer of indirection. Make it a trait:
>
>       boost::impl_ptr::traits::implementation_for<T, Enable>::type
>
> could be made to refer to the user-defined implementation type. That way
> the "pain" is only in 1 line where the trait is specialized.

Before we embark on exploring other possibilities, is there something in 
particular that you object to in the proposed

template<> struct boost::impl_ptr<Foo>::implementation

declaration?