Simon Willison’s Weblog

How Regexes Work (via) They’re just simplified syntax for constructing a state machine

Posted 25th November 2003 at 12:27 am

Recent articles

Hacking the WiFi-enabled color screen GitHub Universe conference badge - 28th October 2025
Video: Building a tool to copy-paste share terminal sessions using Claude Code for web - 23rd October 2025
Dane Stuckey (OpenAI CISO) on prompt injection risks for ChatGPT Atlas - 22nd October 2025

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe