[C++-sig] instantiate python classes in c++

[Gregor Burger]

hi all,

is it possible to use boost.python to define classes
in a script (like in the one below), register the defined
classes and later on create instances of the class?

from cd3 import *

class MyNode(Node):
	def init(self, start, stop, dt):
		in_flow = Flow()
		self.addInPort(in_flow)

	def f(self, time, dt):
		return dt


register_node(MyNode)

registering of the class is working also instantiating
the class. but it seems that when i call init(...) and f(...)
afterwards the namespace and all imports are lost. so
in_flow = Flow() raises an global name Flow undefined. The wrapping
of Flow works on first execution.

Is it possible to provide the same globals and locals to call_method
so that Flow and other classes are defined?

thanks in advance.

gregor burger
university of innsbruck

the wrapped Node looks like this:

struct NodeCallback : Node {
	NodeCallback(PyObject *p) : self(p) {
		Py_INCREF(self);
	}

	virtual ~NodeCallback() {
		Py_DECREF(self);
	}

	void init(int start, int stop, int dt) {
			call_method<void, int, int, int>(self, "init", start, stop, dt);
	}

	int f(int time, int dt) {
		return call_method<int, int, int>(self, "f", time, dt);
	}

	void addInPort(object o) {
		std::string name = extract<std::string>(o.attr("__name__"));
		std::cout << "adding in port " << name << std::endl;
	}

	PyObject *self;
};