Document sqlnbfmt as a custom SQL formatter plugin

[flyersworder]

Hi! I maintain sqlnbfmt, a SQL formatter for notebook cells. We recently added a jupyterlab-code-formatter integration so users can format SQL in notebook cells interactively (toolbar, shortcuts, format-on-save).

It handles:

• SQL in Python strings (query = "SELECT ...")
• SQL in function calls (pd.read_sql("SELECT ..."), cursor.execute(...))
• %%sql / %sql magic cells
• F-string placeholders (f"SELECT * FROM {table}")

Setup

pip install sqlnbfmt jupyterlab-code-formatter

# ~/.jupyter/jupyter_notebook_config.py
from sqlnbfmt.jupyterlab_integration import register
register()  # or: register(dialect="postgres")

Then "Apply SQL Notebook Formatter" appears in the Format Cell menu.

Request

Would you be open to mentioning sqlnbfmt in the docs as an example of a custom formatter plugin? This could go in the README or a "Third-party formatters" section. Happy to submit a PR if that's preferred.

This would also help users discover that custom formatters are possible — I noticed #231 requesting entry point support, and documenting a working example might be useful context for that discussion.

[krassowski]

jupyter_notebook_config.py

jupyter_server_config.py for modern usage?

I think that your package could also be able to ship with a server extension to automatically register itself. In any Case I think mentioning it in the documentation here is worthwhile.

[flyersworder]

Good catch on jupyter_server_config.py — fixed in our docs. Thanks!

The server extension idea is great. We'll look into shipping one so that pip install sqlnbfmt auto-registers the formatter with jupyterlab-code-formatter (no manual config needed). Will follow up here or with a docs PR once that's ready.