Re: Problem with 'template' as a qualifier

[John Fine <johnsfine@xxxxxxxxxxx>]

Rodolfo Lima wrote:
> It seems that the '::' tells the compiler that what precedes it is a 
> type (when the token is followed by another ::), so the 'typename' 
> qualifier is only to disambiguate the last token.
In a more general case, the X in X::Y can be a namespace or a type (I 
hope I'm not forgetting something).

In X::Y::Z when X has already been identified as a type (templated, so 
its internals are unknown), I think Y might still be a namespace, but 
I'm very unsure (haven't tested).  Anyway, some of the compilers I use 
insist on being told that Y is a type.
In X::template Y<T>::Z it is even clearer that Y<T> must be a type, but 
I wasn't sure the compiler didn't still need to be told.  I've never 
been clear on what typename qualifies and when you need it.
> My rant about 'typename' is that we have to tell the compiler that 
> we're dealing with types even if it makes no sense for it to be a value.
If rants did any good for the glaring flaws in the C++ standard, I'd be 
ranting quite a bit.  The only real rant is about the standards 
committee placing certain pointless extremes of intellectual purity 
above the usability of the language.

Anyway, I thought your issue was with template rather than with 
typename.  I'd prefer if the standard made the compiler deduce template 
in cases that can't be parsed any other way, rather than make the 
programmer clutter the code with it.  But for template, at least I 
understand why deducing it would be hard on the structure of the 
compiler and I understand when it is needed and what it qualifies.