Xah Talk Show 2025-08-31 Ep695 emacs lisp, most commonly used functions, fill region problems, etc

video summary

by ai

The video covers several topics related to Emacs Lisp and text editing.
It begins with a discussion on the most frequently used Emacs Lisp functions and shows a script to identify them (1:52).

The main part of the video focuses on the fill-region command in Emacs (5:48).
The speaker explains that this command reformats paragraphs to fit a specified width (like 80 characters per line) and traces this convention back to punch cards and early Unix systems (7:53).
A key point is that while fill-paragraph can shorten lines, there isn't a built-in command to easily revert them to a single long line, which the speaker addresses with their custom reformat-lines command (12:56).
The speaker also highlights issues with Emacs' fill commands, noting they can unexpectedly add or remove characters, making them unsuitable for source code (13:54).

Towards the end, the speaker demonstrates asking an AI (Grok 4) about the origin of the fill-region command's name (17:46) and shares their thoughts on the value of AI for learning (18:57).
The video also touches on databases like SQLite and programming languages like Prolog in a Q and A session (22:39).

2025-08-31