[Development] templated QObjects [was: Re: We are planning to upgrade qdoc to use clang for parsing C++]

[Milian Wolff]

On Mittwoch, 2. März 2016 09:47:33 CET Thiago Macieira wrote:
> On quarta-feira, 2 de março de 2016 16:48:08 PST Milian Wolff wrote:
> > A simple solution would then be a macro for an explicit instantiation,
> > similar  to what we already do with
> > Q_DECLARE_LOGGING_CATEGORY/Q_LOGGING_CATEGORY. Only there then would moc
> > generate the static meta object. That should work, no?
> 
> That is the case I mentioned before: the template class's author needs to
> know each and every possible instantiation ahead of time and instantiate
> them. Unlikely to be acceptable use-case.

For the use-case I have in mind, i.e. templated models, it would just fine. 
Note that I did not propose to have the macro for the instantiation where the 
template gets defined. Rather, I imagine users of the template to do that on 
demand.

It's like QMetaType, no? We can, optionally, supply a set of instantiations 
for common types in the library. All others will be done by the user on-
demand. If he then triggers an ODR violation, he can solve it by sharing the 
common code.

Cheers

-- 
Milian Wolff | milian.wolff at kdab.com | Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts
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