bengioe / PyVariable

PyVariable is a set of C++ tools that allow easier interaction between Python and C++ in terms of creation, manipulation, and access of Python Objects.

PyVariable

I first started writing this code out of frustration of having to make huge functions using the Python C API for very simple tasks. Of course, I was aware of the existing tools such as boost::python, but hey, making your own tools is always fun!

Intent

PyVariable's first intent was to provide a C++ class that would act as Python object would, to a certain extent. To that purpose, a PyVariable instance tries to be anything a PyObject* can be, and uses the right functions of the Python C API to acheive the intended purpose, hopefully correctly following the POLE.

Example

Check out test.cpp!

Installing and Stuff

You need the Python 2.x headers, usually installed alongside Python itself. Support for Python 3.x is really not guaranteed since functions in the C API were changed &/| deprecated.

Other than that you can either add the few files (2 .cpp/2 .h) to your running project or try making a shared object with gcc.

Tips and Bits

• Try not to pass PyVariable*'s around. PyVariable objects contain only a PyObject* (and some other stuff, see next point) and thus are almost only as big as pointers. Use references if you like. Plus, reference count is well managed within PyVariable, so you shouldn't be afraid of copies and other passing around.

• Sometimes methods malloc data which shouldn't be freed when those methods return (such as c_str()). This data is freed when the PyVariable is freed/deleted (not the PyObject within).

• You can pass 3 types of C functions to Python:

  • PyObject* (*)(PyObject* self,PyObject* args)
  • void (*)(PyVariable args)
  • PyVariable (*)(PyVariable args)

  args will always be a tuple containing the arguments passed.

• Please report any bugs you see, with minimal code if possible!