[Python-Dev] New calling convention to avoid temporarily tuples when calling functions

[Victor Stinner]

2016-08-22 10:01 GMT+02:00 Victor Stinner <victor.stinner at gmail.com>:
> The next step is to support keyword parameters. In fact, it's already
> supported in all cases except of Python functions:
> https://bugs.python.org/issue27809

Serhiy Storchaka proposed to use a single C array for positional and
keyword arguments. Keyword arguments are passed as (key, value) pairs.
I just added this function:

     PyAPI_FUNC(PyObject *) _PyObject_FastCallKeywords(
                                PyObject *func,
                                PyObject **stack,
                                Py_ssize_t nargs,
                                Py_ssize_t nkwargs);

The function is not used yet. Serhiy proposed to enhance the functions
to parse arguments to support this format to pass arguments which
would allow to avoid the creation of a temporary dictionary in many
cases.

I proposed to use this format (instead of (PyObject **stack,
Py_ssize_t nargs, PyObject *kwargs)) for a new METH_FASTCALL calling
convention for C functions:
https://bugs.python.org/issue27810

Victor