pybind11 shadow classes for C++ objects

pybind11.md

Intro

Have you ever wondered how to create XJet like python bindings to your own C++ classes, with a modern python binding package? Wonder no longer!

// Example to allocate a class in C++, wrap it as a python class and call a
// member of it from python.
//
// 2019-10-08 Tue

#include <stdio.h>
#include <pybind11/pybind11.h>
#include <pybind11/embed.h>

using namespace std;
namespace py = pybind11;

class Cat
{
    public:
        Cat() {}
        int m_counter = 0;

    void meow() { printf("meeeoww %d!\n", ++m_counter); }
};

class Application
{
    public:
    Application()
    {
        // Create application modules
        m_cat = make_shared<Cat>();

        // Construct python wrappers for them
        py::module m("MyApp");
        py::class_<Cat, shared_ptr<Cat>>(m, "CCat")
            .def("meow", &Cat::meow);

        // Assign them to the "application" dictionary
        m.add_object("Cat", py::cast(m_cat));

        // Assign the module to the global dictionary
        py::globals()["MyApp"] = m;
    }

    shared_ptr<Cat> get_cat() { return m_cat; }

    void run_python(const string& pycode)
    {
        py::exec(pycode);
    }
  
    private:
    shared_ptr<Cat> m_cat;
};
  
int main(int argc, char *argv[])
{
    py::scoped_interpreter guard{};
  
    Application app;

    app.get_cat()->meow();
    app.run_python("MyApp.Cat.meow()\n"
                   );
}