Hello,

is it possible to define aliases of templates ?

I'd like to do something like :
template <int N> struct S;

template <int N> typedef S<N> Alias;

so that I can use either Alias<N> or S<N>.

I'm aware that a better design would be to do
template <int N> struct Alias  { S<N> proxied; };
But this is far longer to code, and while prototyping
I prefer the quickest solution.
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Thierry Grellier wrote:
>
> Hello,
>
> is it possible to define aliases of templates ?
>
> I'd like to do something like :
> template <int N> struct S;
>
> template <int N> typedef S<N> Alias;
>
> so that I can use either Alias<N> or S<N>.
>
> I'm aware that a better design would be to do
> template <int N> struct Alias  { S<N> proxied; };
> But this is far longer to code, and while prototyping
> I prefer the quickest solution.

A solution that requires far less code is:

 template <int N> struct Alias : public S<N> {};

One other alternative is:

 template <int N> class name1
 {
  typedef S<N> name2;
 };

Then name1<T>::name2 would be an alias for S<N>. A little lumsy, but
pretty much foolproof.
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Thierry Grellier <t.grellier@arexsys.com> writes:
> is it possible to define aliases of templates ?
> I'd like to do something like :
> template <int N> struct S;
> template <int N> typedef S<N> Alias;
> so that I can use either Alias<N> or S<N>.

No. The best you can do with C++ is

template <int N> struct Alias { typedef S<N> t; };

and then use Alias<N>::t instead of S<N>.
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James Kuyper <kuyper@wizard.net> writes:
> A solution that requires far less code is:
>  template <int N> struct Alias : public S<N> {};

This would force all the constructors of S to be repeated in Alias.
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Hyman Rosen wrote:
>
> Thierry Grellier <t.grellier@arexsys.com> writes:
> > is it possible to define aliases of templates ?
> > I'd like to do something like :
> > template <int N> struct S;
> > template <int N> typedef S<N> Alias;
> > so that I can use either Alias<N> or S<N>.
>
> No. The best you can do with C++ is
>
> template <int N> struct Alias { typedef S<N> t; };
>
> and then use Alias<N>::t instead of S<N>.

Thanks for the idea. I'll try to fing a meaningful t name. I couldn't go
for inheritence because I've got overloaded operators.

Thierry
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