🚀 go-pugleaf

Pulkkinen Esa (esap@cs.tut.fi) wrote:
> This raises immediately the following questions:

> template <class T> namespace { // an unnamed namespace template - allowed?
>   int i; // how many copies of this will be in the program?
>                 // what's the syntax for accessing the variable?
>                 // i<T> ?  <T>::i ?
>   typedef vector<T>::iterator vector_iterator;  // is this the same
>                                                 // as a typedef template?
> }

  From the general point of view such lines would not be allowed becouse 
they can be written as 
template <class T> namespace unique { 
 ...
}
using namespace unique<T>;

but namespace unique is predefined and template names can not be 
overloaded.  
 

> template <class T> namespace X { int f(); }

> template <class T> using X<T>::f(); // Allowed?
> template <class T> using namespace X<T>; // Allowed?

> [points to justify namespace templates removed]

I agree that such lines should not be allowed. But this would not be another
rule about template namespace, I propose to extend the template to allow 
template namespace declarations, NOT a template "using" declarations.
And this does not prohibit next lines:

template<class T> namespace A {
   void f(T);
   ...
}    

template<class T> namespace B {
   using A<T>;
   ...
   void g(T t) { return f(t); } // call A<T>::f
}

> >  3. It makes C++  easy to study, because somebody will have to know only 
> >the general idea about templates and how to apply them to any C++ elements
> >(function, class, namespase,...).  

> This would only be true if also typedef templates and union templates
> were introduced too.
> -- 

I agree that reason 3 should be removed. But here is another reason:
   Non-template class with only public static members can be replaced by 
namespace declaration. But why template class with only public static 
members could not be replaced by corresponding template namespace?
   
--
Regards, Igor Boukanov (igor.boukanov@fi.uib.no).
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