[Python-Dev] C-level duck typing

["Martin v. Löwis"]

 > And, we want this to somehow work with existing Python; we still
 > support users on Python 2.4.

This makes the question out-of-scope for python-dev - we only discuss
new versions of Python here. Old versions cannot be developed anymore
(as they are released already).

> typedef struct {
> unsigned long extension_id;
> void *data;
> } PyTypeObjectExtensionEntry;
>
> and then a type object can (somehow!) point to an array of these. The
> array is linearly scanned

It's unclear to me why you think that a linear scan is faster than
a dictionary lookup. The contrary will be the case - the dictionary
lookup (PyObject_GetAttr) will be much faster.

Just make sure to use interned strings, and to cache the interned strings.

Regards,
Martin