Re: [boost] Typeof registration of partially specialized templates

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2006-01-26 16:07:22

"Tobias Schwinger" <tschwinger_at_[hidden]> wrote
> Arkadiy Vertleyb wrote:
> > "Tobias Schwinger" <tschwinger_at_[hidden]> wrote
> >>Arkadiy Vertleyb wrote:
> >>>"Tobias Schwinger" <tschwinger_at_[hidden]>
> >>>
> >>>>Would it be possible to allow Typeof registration of partially
specialized
> >>>>templates?
> >>>
> >>>It seems that it would be very hard to achieve any decent syntax :-(
> >>>
> >>
> >>Without thinking about the macro interface for a moment it would be
technically
> >>possible, wouldn't it?
> >
> > Yes, I think it would.
>
> It's hot ;-).
>
> > Right now I am skeptical about the possibility to implement anything
> > readable, but you are welcome to convince me otherwise ;-)
>
> Well, after reading Dave's post I believe it might be possible to allow
>
>      REG_SPEC((typename T),(std::set<T,std::less<T>,std::allocator<T> >))

Considering my previous post... we could probably make it:

REG_SPEC((typename),(std::set<P0,std::less<P0>,std::allocator<P0> >))

Where P0 stands for "the first parameter".  We already use this techinique
in dependent template parameters.  Then (typename) is free to use for other
purposes.

The above syntax is most attractive, but I think there will be a problem
specializing on a type that was calculated by the means of template
metaprogramming...

>
> (with some extra work that is -- by specializing for a function with a
special
> return type).
>
> Here are some more straightforward versions which do not seem that hard to
read
> to me (although they involve counting commas):
>
>      REG_SPEC((typename T),2,(std::set<T,std::less<T>,std::allocator<T>
>))
>      //                    ^--- comma count
>
> or
>
>      REG_SPEC((typename T),3,(std::set<T,std::less<T>,std::allocator<T>
>))
>      //                    ^--- tuple arity
>
> or
>
>      REG_SPEC((typename T),(3,(std::set<T,std::less<T>,std::allocator<T>
>)) )
>      //                    \--- pp-array used as a
string -----------------/
>
>
> Anything that works with your taste among it?

All of them are much better than using ")(" :-)

> <by the way>
> Our list correspondence is often hard to read because our clients seem to
> disagree on where to break lines.
> I set the line width down to 80 characters (which I figure should be
acceptable
> -- it used to be 82 for quotes plus code) but the problem seems to
persist. Is
> there anything that you can do about it, perhabs?
> </by the way>

I also switched to 80 (was 50) -- let's see if it works...

Regards,
Arkadiy