About this book

who wrote it, how the site works, what it keeps

Author

The book and the site are written by Lunario.

How the console works

Code runs right in your browser. JavaScript runs in a separate thread, so an endless loop can be stopped without losing the page. Python is Pyodide: the real CPython compiled to WebAssembly. It is downloaded from this site once, about 12 MB, and then comes from the browser cache.

Nothing you type in the console leaves your device.

A Run button stands only under listings that work on their own. Many listings in the book are fragments of a larger program, they are there to be read. The note «matches the book» appears where the site, when it was built, got exactly the output printed in the book.

Privacy

No accounts, no analytics, no cookies, no third-party servers. The site remembers your language, theme, console width, the article you stopped at and what you typed in the editor. All of it stays in your browser's local storage. Clearing the site's data in the browser erases it.

Copyright

Fonts and software

Text: a subset of PT Serif and PT Sans by ParaType, renamed for the site as the license requires. SIL Open Font License 1.1 — license text 1, license text 2
Code: a subset of JetBrains Mono. SIL Open Font License 1.1 — license text
Python in the browser: Pyodide, source at github.com/pyodide/pyodide. Mozilla Public License 2.0 — license text
Python standard library. Python Software Foundation License — license text