pygccxml-development

[pygccxml-development] Wrapping abstract C++ classes

[Gustavo C. <gjc...@gm...>]

  Is it possible to wrap a C++ class that has pure virtual functions?  I am
getting a compilation error below; what should I do?

PS: those pure virtual methods are being exclud()ed by me.

/usr/include/boost/python/object/value_holder.hpp:66: error: cannot declare
field 'boost::python::objects::value_holder<Queue_wrapper>::m_held' to be of
abstract type 'Queue_wrapper'
debug/bindings/python/ns3.cpp:58: note:   because the following virtual
functions are pure within 'Queue_wrapper':
./debug/ns3/queue.h:91: note:   virtual bool ns3::Queue::DoEnqueue(const
ns3::Packet&)
./debug/ns3/queue.h:92: note:   virtual bool
ns3::Queue::DoDequeue(ns3::Packet&)
./debug/ns3/queue.h:93: note:   virtual bool
ns3::Queue::DoPeek(ns3::Packet&)
Compilation failed

-- 
Gustavo J. A. M. Carneiro
"The universe is always one step beyond logic." -- Frank Herbert

Re: [pygccxml-development] Wrapping abstract C++ classes

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

On 5/5/07, Gustavo Carneiro <gjc...@gm...> wrote:
>   Is it possible to wrap a C++ class that has pure virtual functions?  I am
> getting a compilation error below; what should I do?
>
> PS: those pure virtual methods are being exclud()ed by me.

If you exclude them, than I guess you don't want Python user to create
instances of the class and derive from it. If I am right, than you
should use no_init:

http://boost.org/libs/python/doc/v2/class.html.

The only way to tweak Py++ to generate no_init for the class is to
exclude all class constructors.

HTH.

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

Re: [pygccxml-development] Wrapping abstract C++ classes

[Gustavo C. <gjc...@gm...>]

On 05/05/07, Roman Yakovenko <rom...@gm...> wrote:
>
> On 5/5/07, Gustavo Carneiro <gjc...@gm...> wrote:
> >   Is it possible to wrap a C++ class that has pure virtual functions?  I
> am
> > getting a compilation error below; what should I do?
> >
> > PS: those pure virtual methods are being exclud()ed by me.
>
> If you exclude them, than I guess you don't want Python user to create
> instances of the class and derive from it. If I am right, than you
> should use no_init:
>
> http://boost.org/libs/python/doc/v2/class.html.
>
> The only way to tweak Py++ to generate no_init for the class is to
> exclude all class constructors.


  Well, assuming the code below is correct, it doesn't seem to make any
difference:

    for meth in Queue.constructors():
        meth.exclude()

 But, anyway, I just white-listed the pure virtual methods and now it
compiles.  They won't work in runtime because they handle unregistered
parameters, but that is a lesser evil.

  Thanks anyway,

-- 
Gustavo J. A. M. Carneiro
"The universe is always one step beyond logic." -- Frank Herbert

Re: [pygccxml-development] Wrapping abstract C++ classes

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

On 5/5/07, Gustavo Carneiro <gjc...@gm...> wrote:
> On 05/05/07, Roman Yakovenko <rom...@gm...> wrote:
> > On 5/5/07, Gustavo Carneiro <gjc...@gm...> wrote:
> > >   Is it possible to wrap a C++ class that has pure virtual functions?  I
> am
> > > getting a compilation error below; what should I do?
> > >
> > > PS: those pure virtual methods are being exclud()ed by me.
> >
> > If you exclude them, than I guess you don't want Python user to create
> > instances of the class and derive from it. If I am right, than you
> > should use no_init:
> >
> > http://boost.org/libs/python/doc/v2/class.html.
> >
> > The only way to tweak Py++ to generate no_init for the class is to
> > exclude all class constructors.
>
>   Well, assuming the code below is correct, it doesn't seem to make any
> difference:
>
>     for meth in Queue.constructors():
>         meth.exclude()
>
>  But, anyway, I just white-listed the pure virtual methods and now it
> compiles.  They won't work in runtime because they handle unregistered
> parameters, but that is a lesser evil.

If you had some free time, could you submit a complete example that
show a problem?

Thanks

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