Simon Willison’s Weblog

Simple Top-Down Parsing in Python. Eye-opening tutorial on building a recursive descent parser for Python, in Python that uses top-down operator precedence.

Posted 19th July 2008 at 11:37 pm

Recent articles

My Lethal Trifecta talk at the Bay Area AI Security Meetup - 9th August 2025
The surprise deprecation of GPT-4o for ChatGPT consumers - 8th August 2025
GPT-5: Key characteristics, pricing and model card - 7th August 2025

compilers 16 effbot 4 fredrik-lundh 7 parsing 12 python 1171 recursivedescent 1

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