Re: [boost] Factory library new version

From: Federico Stella (f.stella_at_[hidden])
Date: 2005-05-04 17:29:48

* martedì 03 maggio 2005, alle 21:56, Robert Geiman scrive:

[...]

> there is another difference between our two implementations.  Mine is
> specifically made to register classes dynamically during runtime by
> calling the register() function of the factory object, while yours
> appears (and please correct me if I'm wrong) to be done via compile
> time.  In other words, to add a derived3 class you must actually edit
> the boost::factory typedef to specifiy derived3 in the mpl::vector.
Yes, you're right.

[...]

>>Ideas? Comments? Bugs?

> Overall I like it!  Quite an interesting approach to a problem I
> spent a lot of time working on.
Very well!

> Two things tho:

> I'm not certain I like the fact that you must create a builder class
> instance for every class you register.  Any way to get rid of this or
> hide it in the factory class implementation itself?
Yes, it was boring... The main reason is declaring factory and registering
builders for types before entering main(). I've just upload a new version
(factory3.zip) that adds a new member new_creator<type>() for your needs.
I've also updated tutorial for showing this feature.

> Would it be possible to allow for derived classes to be added
> dynamically without the need to edit the declaration of the factory
> object itself?  I know many boost users perfer compile-time solutions
> to run-time solutions, and certainly each of their own uses, but I've
> always like the ability to allow end-users to modify/extend programs
> simply by registering their classes with my factory object (IE, the
> user shouldn't need to recompile my code to do this).
I prefer the compile-time :), but joke aside C++ can't declare class at
runtime so declaring a typedef for all the products at compile-time seems
like a win for less runtime overhead. Maybe you could explain better what
this design lacks?

Fede.