Mypy stub generator

Mypy requires stub files describing the interfaces of modules in order to type-check code that uses them. Writing them is quite tedious so here are some tools to help:

• stub.py generates a dynamically typed stub file for a named module

• lsmod.py gets a list of modules to stub by scraping the module index page on docs.python.org (not ideal, I know)

Requirements

• CPython version 3
• Beautiful Soup version 4 if you want to run lsmod.py (get with pip install beautifulsoup4 or apt-get install python3-bs4)

Usage

Here's roughly what I did to get a mostly working set of stubs.

Decide what to stub:

python3 lsmod.py > modules.txt

Generate the bulk of the stubs (assuming zsh):

for m (`cat modules.txt`) python3 stub.py $m stubs

A couple didn't quite work with the default settings:

rm stubs/{os,tempfile}.py
python3 stub.py os stubs --force-package \
    --hiding MutableMapping --hiding _Environ
python3 stub.py tempfile stubs --hiding _Random

I had to use the original hand-written stubs for another two:

• builtins because the generated stub has some syntax errors around the definitions of any and object

• re because the original stub had some extra interfaces (Match and Pattern, I think) which aren't actually exposed as classes in the python module.