c++ - Boost::Python bindings for classes with inheritance -

i'm trying figure whats wrong autogenerated (with pyste) boost::python code, have no luck far.

there c++ library, magick++, provides 2 classes, magick::drawable , magick::drawablerectangle:

https://www.imagemagick.org/subversion/imagemagick/trunk/magick++/lib/magick++/drawable.h

class magickdlldecl drawablebase:    public std::unary_function<magickcore::drawingwand,void> {...} class magickdlldecl drawable {   public:     // constructor     drawable ( void );     // construct drawablebase     drawable ( const drawablebase& original_ ); ... } class magickdlldecl drawablerectangle : public drawablebase { ... } 

these used arguments image.draw(): https://www.imagemagick.org/subversion/imagemagick/trunk/magick++/lib/magick++/image.h

// draw on image using single drawable void            draw ( const drawable &drawable_ ); // draw on image using drawable list void            draw ( const std::list<magick::drawable> &drawable_ ); 

i'm trying make python bindings it, there autogenned wrappers classes,

http://bitbucket.org/dan.kluev/pythonmagick/src/65d45c998ef3/src/_drawable.cpp

http://bitbucket.org/dan.kluev/pythonmagick/src/65d45c998ef3/src/_drawablerectangle.cpp

http://bitbucket.org/dan.kluev/pythonmagick/src/65d45c998ef3/src/_image.cpp

problem is, due indirect class casts drawablebase drawable, these wrappers not work:

>>> import pythonmagick >>> image = pythonmagick.image() >>> square = pythonmagick._pythonmagick.drawablerectangle(0,0,200,200) >>> image.draw(square) traceback (most recent call last):   file "<stdin>", line 1, in <module> boost.python.argumenterror: python argument types in     image.draw(image, drawablerectangle) did not match c++ signature:     draw(magick::image {lvalue}, std::list<magick::drawable, std::allocator<magick::drawable> >)     draw(magick::image {lvalue}, magick::drawable) # abstract drawable() work: >>> image.draw(pythonmagick._pythonmagick.drawable()) >>>  

is there better way handle write own draw() wrapper in c++, cast pyobject drawable?

if want bp implicitly convert objects foy , must tell bp thay implicitly convertable. put in bp::code:

boost::python::implicitly_convertible<sourcetype,desttype>(); 

i not know how induce pyste this.