How tally counts, in three stops

The story of how tally counts, in three parts. They are the function that counts, the tests, and the option --top.

Each part shows the code as it was then. The walk leaves out the other changes. They made the command that reads a file, ruff and the corpus, and the types and the docstring. They also made the function top and the report. The third part uses some of them.

Each part ends with a section called What changed. It lists every file that the part changes, with a link to the file, and then the whole diff of each file, folded. A lockfile and a binary file have a link alone. The text above it explains the change.