Re: Registries [2]

Daniel Wallin <[email protected]> writes:

> At 01:26 2003-07-27, David Abrahams wrote:
>>Daniel Wallin <[email protected]> writes:
>> >>Hmm, if there was really a mutual dependency we might have an issue,
>> >>but we could still handle it with a simpler mechanism that simply
>> >>deferred imports until initialization was completed.
>> >
>> > I guess, but it would be nice to handle it without introducing code in
>> > the dispatch functions. Which is the only place I can think of where
>> > we could defer importing to.
>>
>>In Boost.Python, the module initialization function is special; we
>>actually generate it with a macro and it calls what the user wrote
>>(for exception-handling purposes), so we can easily generate code
>>there to handle any deferred imports.
>
> Right, but how do you call this code after all other modules has been
> initialized?

You keep a count of modules being initialized in each thread and when
it falls back to zero you do the imports.

> Also, at least in lua. Modules could be loaded at any time, so there isn't
> really a point where we can assume everything is loaded and import
> converters.

Can't you do something similar to the above?

>> >> > How are extensions to be registered in this central registry? In my
>> >> > previous post I proposed that they should be registered with a
>> >> > string literal identifier.
>> >> >
>> >> >    register_extension("my_extension");
>> >> >
>> >> > How does this fit in with pythons module system? (Note that we are
>> >> > really registering the extension, and not modules).
>> >>
>> >>Every extension is a module (not nececssarily the other way around),
>> >>so I see no reason not to register the extension by its module name
>> >
>> > I guess in python you can ask the interpreter state for the current
>> > module name?
>>
>>Erm, I'm not sure you can.  It is supplied as part of the module
>>initialization function; in fact, it is stored in the module object as
>>its __name__ attribute, so we can get it thence, assuming we can get
>>to the module.
>
> Ok.
>
>> > In lua this isn't possible though, so we would need some user defined
>> > identifier instead.
>>
>>You've gotta have the module or its name stored somewhere, dontcha?
>
> Other than in the .so filename? No.

Why not just store it then?  When you create it, stick a string in its
__name__ attribute.

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



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