Feature or enhancement

Proposal:

In the cpython codebase PyTuple_Pack is used at various places (https://github.com/search?q=repo%3Apython%2Fcpython+PyTuple_Pack&type=code). The execution is not very fast as the implementation uses va_arg internally. For the 1- and 2 argument case we can improve performance by providing a direct implementation.

Using PyTuple_Pack2 (example implementation main...eendebakpt:cpython:putuple_pack2) performance of components like pairwise can be improved. See https://discuss.python.org/t/nwise-itertools/51718/22

• Can we add Py_TuplePack1 and Py_TuplePack2 to the cpython interface? If so, should it be in the public or private API.
• If we add Py_TuplePack2 should we use it at all places applicable, or only the few performance critical ones?
• An alternative for Py_TuplePack1 that already exists is the internal _PyTuple_FromArray with second argument 1.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response