ENB: the wax-off script and stub files

[Edward K. Ream]

Yesterday I started work on the wax-off script. This script strips annotations from function/method signatures. I want this script because I don't want to clutter Leo's sources.

The original idea was to write a second wax-on script that would restore the signatures, but Aha! There is another way: let the wax-off script write the original signature to the log, in stub file format. That is, each signature will end with "...". I can then copy the log to a stub (.pyi) file in leo/mypy_stubs.

I avoided stub files while working on annotations for several reasons:

- It was easiest to add the annotations directly to the sources.

- I was (and still am) unsure about how annotations in the stub file work with annotation in the actual source file. Does mypy merge them, or does one source take precedence?

The question might go away if the source file contains no annotations.  I'll do some overdue experiments today to find out.

Yes, keeping stub files up to date will be a recurring issue, but that will become a problem only when using mypy, which is likely to happen rarely :-) More importantly, devs can use mypy's --disallow-untyped-defs option to ensure that stub files cover all new methods.

Summary

Stub files (.pyi files in leo/mypy_stubs) should allow Leo to get the benefits of type annotations without cluttering the code.

mypy can warn if stub files are not up to date with their corresponding files.

Oh joy. There is no need for a wax-on script. This is a big deal because there is no need to tell wax-on what the annotations should be!

The wax-off script will be part of Leo 6.4, but it may be a few days before I complete it.

Edward

P. S. This regex finds all defs in a file:

def_pat = re.compile(

    r'def\s+([\w_]+)\s*\((.*?)\)(.*?):',

    re.MULTILINE + re.DOTALL)

wax-off can use this to write stubs.

The sub-pattern \((.*?)\) correctly finds the argument list, but regexes do not suffice to parse individual arguments. For that, wax-off will need a simple text scanner.

EKR