[Python-Dev] PEP 580/590 discussion

Jeroen Demeyer J.Demeyer at UGent.be
Mon May 6 03:43:46 EDT 2019

On 2019-05-06 00:04, Petr Viktorin wrote:
> - Single bound method class for all kinds of function classes: This
> would be a cleaner design, yes, but I don't see a pressing need. As
> PEP 579 says, "this is a compounding issue", not a goal. As I recall,
> that is the only major reason for CCALL_DEFARG.

Just a minor correction here: I guess that you mean CCALL_SELFARG. The 
flag CCALL_DEFARG is for passing the PyCCallDef* in PEP 580, which is 
mostly equivalent to passing the callable object in PEP 590.

The signature of PEP 580 is

func(const PyCCallDef *def, PyObject *self, PyObject *const *args, 
Py_ssize_t nargs, PyObject *kwnames)

And with PEP 590 it is

func(PyObject *callable, PyObject *const *args, Py_ssize_t nargs, 
PyObject *kwnames)

with the additional special role for the PY_VECTORCALL_ARGUMENTS_OFFSET 
bit (which is meant to solve the problem of "self" in a different way).

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