In the following example

  template< class T > f( T ) {

      typename T::X x = 35;

      /* ...  */
    }

why is it necessary to use the keyword typename?
I thought the new standard says that binding of a name occurs at
instantiation time, if the name depends on a template argument.

So, this is the case here for X, and f should be instantiated when T
is known. But then we have no problem determining what X is.

Where is the rationale for the keyword typename then?

 [Moderator's reply: although the name is *bound* at
 instantiation time, the code is *parsed* when it is first
 encountered.  Because of a long-standing ambiguity in the
 grammar of C, the compiler needs to know whether nor not a name
 is a type name in order to merely parse it.  In C, this is
 normally handled by some sort of feedback from the compiler
 to the lexer.  But in C++ templates, sometimes even that is
 not enough, and so an explicit `typename' is required to resolve
 the ambiguity. -fjh.]

Martin
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Signatures are a waste of bandwidth
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