[boost] Re: Specializing std::swap? (Something I posted to comp.std.c++.)

From: Valentin Bonnard (Bonnard.V_at_[hidden])
Date: 2000-01-18 14:01:35

Darin Adler wrote:

> I now understand that the standard allows specializing a function template
> but not partially specializing a function template.

Correct

> I'm not sure what partially specializing a function template would mean. 

???

(Partially specializing a function template means partially specializing 
a function template.)

> For
> example, take my original example from my comp.std.c++ posting. Make class U
> be a class template instead:
> 
>     // header file
> 
>     #include <algorithm>
> 
>     namespace N {
> 
>     template<typename T>
>     class U
>     {
>     public:
>         // ...
>         void swap(U&);
>         U& operator=(const U&);
>         // ...
>     };
> 
>     }
> 
>     namespace std {
> 
>     template<typename T>
>     inline void swap(N::U<T>& one, N::U<T>& other)
>     {
>         one.swap(other);
>     }
> 
>     }

> Is the std::swap specialization now a partial specialization? 

As written it's a overload.

Had you wrote:

template<typename T>
void std::swap<N::U<T> > (N::U<T>& one, N::U<T>& other)
{...}

It could only have been a partial specialisation (if that 
kind of things existed).

[ I don't understand where partial/explicit specialisation 
  notions are from and how they are intended to work. Is it 
  possible to rewrite the whole thing (all the sections 
  dealing with specialisation) with a DR ? ]

-- 
Valentin Bonnard