🚀 go-pugleaf

>>>>> Eugene Radchenko <eugene@qsar.chem.msu.su> writes:

> 1) Clause [temp.res] verse 1 requires that all types dependent on the
> template parameter must be qualified by 'typename' keyword - supposedly to
> allow checking the template syntax. But it does not help anything as _each_
> instance will have to be checked anyway:

Requiring 'typename' allows syntactic analysis and some name binding
to be done at the point of definition of the template.  Older
implementations do all name binding at the point of instantiation,
which was thought to be confusing.

Each instance will indeed have to be checked, but only for semantic
correctness, not syntactic.

> 2) Clause [temp.dep] verse 5 states that base class scope names hide the
> template parameter:

This is for orthogonality.  Think of the template header as creating a
special scope around the class; name lookups in class scope look in the
current class, then in base classes, then in the surrounding scope.

Note that template parameters used as base types are not affected by this
rule, since name binding is done on the template definition, before the
base is known.

> 3) Clause [temp.arg.explicit] verses 2-3 requires that for explicit arg in
> member template to be present it must be qualified by 'template' keyword,
> e.g.
>      X *p; p->template alloc<200>();
> But to use operator -> we need X class definition anyway - so we know that
> alloc() is a template.

It is needed in some situations where we do not have the X class definition
-- in template definitions, like with typename.

Jason
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