Re: [pygccxml-development] Py++ generates wrappers for final classes

[Roman Y. <rom...@gm...>]

On 7/9/07, Julian Scheid <jul...@rs...> wrote:
> Hello,
>
> I've run into a problem with Py++ (both with 0.9.0 and with trunk) when
> trying to expose a class like this:
>
>    class Foo
>    {
>     public:
>      virtual void bar() {}
>     private:
>      Foo() {}
>    };
>
> Py++ will generate a wrapper for Foo (since it contains a virtual
> function) when it shouldn't. Firstly, the generated code will not
> compile because the wrapper is derived from Foo and Foo cannot be used
> as a base class (Foo is final because it has no public or protected
> constructors.)

What compiler do you use? I just checked this on MSVC 7.1 and it works fine.
I attach the generated code.

>
> And it doesn't make sense to generate a wrapper for Foo in the first
> place because Foo is final, and so function bar() cannot be overridden
> anyway.

May be you are right, I should think about it.

> In the long term, I guess the proper fix is to not create wrappers for
> final classes.

There is no such definition in C++ as "final class". Private
constructor is "public" for a function or another class. ( friend )

> Is there a short-term workaround for this problem?

Try this:

from pygccxml import declarations

mb.mem_fun('bar').virtuality =
declarations.FUNCTION_VIRTUALITY_TYPES.NOT_VIRTUAL

For me it generated next code:

BOOST_PYTHON_MODULE(final_classes){
    bp::class_< final_classes::Foo, boost::noncopyable >( "Foo",
"documentation", bp::no_init )
        .def(
            "bar"
            , &::final_classes::Foo::bar
            , "documentation" );
}

Anyway I committed new test case "final_classes_tester.py".

> I tried using finalize() from goodie_utils but that didn't work unfortunately.

Basically this is the code contributed by other developers and I don't
support it.

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/