Flexibility of template alias in C++0x

Question

As I understand, template aliases in C++0x will allow us to do the following:

template 
using Dictionary = std::map< std::string, T >;

D         


        

Answer 1

typename is required when a member type follows the :: operator and a template-id precedes it.

The usage of typename you mention isn't specific to template aliases nor is it required unless you're aliasing to a member such as ::type, but that is a common use case.

For example, there's no typename when introducing a simple alias name to an existing template.

template< typename x >
class bar;

template< typename x >
using foo = bar< x >; // no typename needed