PyPy is a very compliant implementation of the Python language.  PyPy
has several advantages and distinctive features: speed (Just-in-Time
compiler), lower memory usage for large programs, sandboxing and
stackless mode.

This script builds PyPy implementation of Python 3.9 from sources.
Beware: this takes up a lot of time and about 5Gb of RAM in a 64bit
system. And still 3Gb on a 32bit system.

Note: This package does conflict with pypy3, overwriting files.

OPTIONAL: pypy or PyPy, available on SBo.
If pypy2 is installed, from binary repackaging using pypy, or from
sources using PyPy, it'll be used instead of CPython2.7, as it is
twice as fast.
PyPy, even for Python3.9, only builds using a Python2.7 interpreter.
pycparser is required only when using Slackware's CPython2.7
for building.

REQUIRES: you need one of pycparser, pypy or PyPy.