Re: [boost] [serialization] Inherited objects

From: David Abrahams (dave_at_[hidden])
Date: 2005-10-11 17:28:31

"Robert Ramey" <ramey_at_[hidden]> writes:

> Hmmm  - here is a situation that I come across:
>
> class my_archive {
> ....
> };
>
> template<class Arg>
> class my_templated_archive{
> };
>
> template<class Archive, T>
> void serialize(Archive & ar, T &t, const unsigned int version){
>     ...
>     ar.template register_type<T>(); // ok - I think
>     ...
> }

Correct.

> void serialize(my_archive & ar, T &t, const unsigned int version){
>     ...
>     ar.template register_type<T>(); // syntax error?  or not?
>     ...
> }

Syntax error, at least unless and until the committee relaxes the
rules.  my_archive is not a dependent type.

> Truth is I can't never keep these kinds of rules straight.

It's pretty simple: does the type of ar depend on a template
parameter?  If so, we don't know whether ar.register_type is a value
or a class template and template is required.  If not, we can simply
look at the type of ar and determine whether register_type is a
template or not, and the template keyword is forbidden.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com