Black vs OCamlFormat

Black is a free, MIT-licensed formatter for Python code that follows PEP 8. It reformats whole files in place and uses a default line length of 88 characters. Its limited style choices are intended to keep code consistent across projects; indentation style cannot be configured. After formatting, Black checks whether the abstract syntax tree remains effectively equivalent and raises an error if the check fails. Install it with pip; it requires Python 3.10 or newer. The documentation lists editor integrations including Emacs, PyCharm, IntelliJ IDEA, Vim, Neovim, Visual Studio Code and Sublime Text, as well as GitHub Actions and doctest workflows. Notebook formatting is available with the jupyter extra, though Black skips cells containing certain magics or invalid syntax. It also includes blackd, an HTTP server that binds to localhost by default. Black is primarily a command-line tool and does not provide a Python interface. Stable releases preserve formatting within the same calendar year when the options match.

OCamlFormat has no write-up on Specifiction yet; its figures are above.