Excellent explanation !

I promise to start a deeper study of the code this weekend in order to minimize bothering you (but not stop, ha ha).


2010/4/9 Barry Scott <barry@barrys-emacs.org>

On 9 Apr 2010, at 15:27, Fernando Libonati wrote:

Two questions ...
a) How can I pass a pointer to a new type object?

Can you get a pointer from a Py::Object? Yes

b) Can I access methods from this pointer?

yes. But it depends on the method. If its
a C++ method then its trivia. If its a python method
on the object that may have been overridden in
a derived class then you need to use a PyCXX helper.

The code below depends on PyCXX trunk that I will release
as 6.2.0 soon.

Like in

class Block : Public PythonClass<Block> {
     Block *parent;
     Block(Py::PythonClassInstance *self, Py::Tuple &args, Py::Dict &kwds):
     : Py::PythonClass< Block >::PythonClass( self, args, kwds )
       // Is this possible ??? or something like this
        parent  = (Block*) args[0];

This does not work on lots of levels.
a) Py::Object just holds a pointer to the PyObject.
b) You cannot cast a PyObject as its not part of the C++ class.
     It contains a pointer to the C++ class.

Use this to make sure you really have a Block:

Py::PythonClassObject<Block> py_block( args[0] );

Now you can get the C++ object pointer:

Block *p_block = py_block.getCxxObject();

To call getFullName you have a couple of choices:

Py::String s( p_block->getFullName() );


Py::TupleN args;
Py::String py_block.callMemberFunction( "getFullName", args );

    Py::Object getFullName( void )
        std::string r = "";
        if( ! parent->isNone() )
            r += Py::String( parent->getFullName()).as_std_string( "utf-8" ) + ".";

/* I want to access parent's methods directly to avoid the overload of calling
   callMemberFunction("getFullName") and many others that I need.
   Is it possible?
   Is callMemberFunction restricted to the exposed ones?
        r += name.as_std_string( "utf-8" );
        return Py::String(r);


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Fernando Libonati
fernando.libonati at gmail.com