On 10 May 2012 14:55, Mateusz Loskot mateusz@loskot.net wrote:

On 10 May 2012 14:01, Stefan Behnel python_capi@behnel.de wrote:

...

You can execute any Python code from your C code. Look for the PyRun_*() functions.

Do you mean something similar to this approach?

/* dynamically generated lengthy class definition */ const char* c = "class A(object): pass";

PyObject* class_a = PyRun_StringFlags(c, ...); PyObject_SetAttrString(module, "A", class_a)

The pseudo-code above is incorrect. I have come up with the following example of dynamically generating new Python class, indirectly through script using class keyword. Such dynamically created class is added to module dictionary:

/* error checks removed for brevity */

static PyModuleDef embmodule = { ... };

PyInit_emb(void) { PyObject* m = PyModule_Create(&embmodule); PyObject* d = PyModule_GetDict(m);

/* Required to allow 'class' use in context of module which is
   not yet complete and ready. Otherwise, error is thrown:
   ImportError: __build_class__ not found
*/
PyObject* builtins = PyEval_GetBuiltins();
PyDict_SetItemString(d, "__builtins__", builtins);

/* Python class is dynamically generated */
const char* c = "class A(object):\n\tpass"; /* sample class */

/* Create object for A class, automatically added to the module

dictionary as noddy.A */ PyRun_StringFlags(c, Py_file_input, d, d, NULL);

return m;

}

This approach works well. If anyone noticed a problem or there is better way to do the same, please let me know.

Best regards,

Mateusz Loskot, http://mateusz.loskot.net