Re: [boost] [PQS] Templatized typedefs; was: Resizable vectors/matrices

From: Leland Brown (lelandbrown_at_[hidden])
Date: 2006-06-20 04:23:01

--- Bronek Kozicki <brok_at_[hidden]> wrote:

> > [Leland Brown wrote:]
> >> BTW, this is where I'd really like to see
> >> templatized
> >> typedefs in C++, allowing us to define:
> >>
> >>     template< int N, type T >
> >>     typedef vector< N, T, false > fixed_vector;
> >>
> >>     template< int N, type T >
> >>     typedef vector< N, T, true >
> >> resizable_vector;
> >>
> >> Thus we'd have:
> >>
> >>     fixed_vector<N,T>
> >>     resizable_vector<N,T>
> >>
> >> while using the common vector template defined
> >> above.

> There is simple way to emulate this, 
> unfortunatelly with different semantics that would
> make metaprograms much more 
> difficult to write:
>    template< int N, type T >
>    struct  resizable_vector : vector< N, T, true >
> {};
> 
> The difficulty comes from the fact that:
>    some_useful_template<vector<10, int, true> >
> and:
>    some_useful_template<resizable_vector<10, int> >
> 
> are two distinct types

True.  And in addition, you don't inherit the
constructors of vector.

-- Leland

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