Re: Inheritance graph

Daniel Wallin <[email protected]> writes:

> At 01:37 2003-08-14, David Abrahams wrote:
>>Daniel Wallin <[email protected]> writes:
>>
>> > FYI, I've messed around with the code in inheritance.cpp /
>> > inheritance.hpp and made it into a real singleton. In this process I
>> > also investigated type importing, and to me it seems complicated to
>> > try to share any data at all between modules.
>>
>>Yes, it's at least complicated.  However, given the size of the cache
>>it does seem expensive not to share when multiple modules interact.
>>
>> > Also, I've looked into library configuration. I ended up with one macro;
>> > BOOST_LANGBINDING_TYPE_INFO, which is the type used for type
>> > identification.
>>
>>Is there some reason we'd have to use a MACRO instead of a typedef??
>
> Well, the point was to allow for easier configuration. With a macro you can
> generally just pass it to the compiler as a command line option, rather than
> editing some library configuration header.
>
>> > I also did something like this (python::type_info used for
>> > illustrative purposes):
>> >
>> >    typedef BOOST_LANDBINDING_TYPE_INFO type_info;
>> >
>> >    template<class T>
>> >    type_info static_type_id(T*, type<python::type_info>)
>>                                 ^^^^^^^^^^^^^^^^^^^^^^^^^
>>What is this argument for??
>
> It's just a thought, configuration by overloading. Define the
> type_info type with BOOST_LANGBINDING_TYPE_INFO and overload the
> type query functions for that type.

I think I understand where you're going with this... but I don't
think this overloading is much help because AFAICT it's just a way to
avoid ODR problems... and there's no way a single extension is going
to use two different TYPE_INFO systems, is there?

> I think we need to discuss the configuration solutions more.

Yeah.  Do people really need to pick arbitrary type_info types?  Can't
we just package a few which are macro-selectable?  I don't like the
idea of storing a type in a macro value, but I guess if it's just for
the purposes of setting up a typedef to be used thereafter, it's fine.


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



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