[C++-sig] make_constructor and extending from python

[Holger Brandsmeier]

Dear list,

how can I have a static member function that acts like a constructor
in a Wrapper, i.e. I have a class that I want to extend from python?

I have a wrapper class around a class (PfemSpace) that has this static
member functions:

  static RCP<PfemSpaceWrapperT> create( ... )
  {
    RCP<PfemSpaceWrapperT> ret(new PfemSpaceWrapperT( ... ));

    ret->setThisRCP(ret);
    return ret;
  }

This method is exported via
  .def("__init__", make_constructor( &ClassWrapperT::create ) )

This works without errors, but when I use this from python via

class PfemSpaceStaticCond(PfemSpace):
  def __init__(self, ...):
    super(PfemSpaceStaticCond, self).__init__(...)

  def visit_createFemData(self):
    print '## [PfemSpaceStaticCond_init] visit_createFemData'

Here I call the constructor that I exported via make_constructor in
__init__(). Unfortunately the member function visit_createFemData that
I override in python never gets called. When I use a "real"
constructor instead of the one exported via make_constructor() then
the function visit_createFemData gets called.

I assume the error is somewhere that with a real constructor
boost::python can call an inplace constructor, while with my
make_constructor it can't. Is there some way to have the needed
functionality with make_constructor?

Note: today I came to the conclusion that I a read constructor instead
of a static member function is not an option for me due to the issues
I wrote in my previous mail "storing weak_ptr to this in classes
extended from python". That previous mail is actually from yesterday,
but it originally got rejected because I send it from a wrong email
address, so I'm sorry that you are receiving two mails from me today.
For a moment I was very happy that this "static constructor-like
function in the Wrapper class" would solve all my problems, but I am
still missing something.

Thanks for your help,
Holger