I'm using it to build things.

Here's an example from the other day. I've always been curious about writing custom Python C extensions but I've never been brave enough to really try and do it.

I decided it would be interesting to dig into that by having Codex build a C extension for Python that exposed simple SQLite queries with a timeout.

It wrote me this: https://github.com/simonw/research/blob/main/sqlite-time-lim... - here's the shared transcript: https://chatgpt.com/s/cd_6958a2f131a081918ed810832f7437a2

I read the code it produced and ran it on my computer to see it work.

What did I learn?

- Codex can write, compile and test C extensions for Python now

- The sqlite3_progress_handler mechanism I've been hooking into for SQLite time limits in my Python code works in C too, and appears to be the recommended way to solve this

- How to use PyTuple_New(size) in C and then populate that tuple

- What the SQLite C API for running a query and then iterating though the results looks like, including the various SQLITE_INTEGER style constants for column types

- The "goto cleanup;" pattern for cleaning up on errors, including releasing resources and calling DECREF for the Python reference counter

- That a simple Python extension can be done with ~150 lines of readable and surprisingly non-threatening C

- How to use a setup.py and pyproject.toml function together to configure a Python package that compiles an extension

Would I have learned more if I had spent realistically a couple of days figuring out enough C and CPython and SQLite and setup.py trivia to do this without LLM help? Yes. But I don't have two days to spend on this flight of curiosity, so actually I would have learned nothing.

The LLM project took me ~1 minutes to prompt and then 15 minutes to consume the lessons at the end. And I can do dozens of this kind of thing a day, in between my other work!