October 6, 2026
Doom in Paul Graham's language: Garry Tan reports a port in about 20 minutes
Garry Tan asked Opus 5.5 in fast mode to port Doom to Bel over dinner.
Garry Tan
@garrytan
Yesterday, over dinner with Tom Brown, Tom Blomfield and Paul Graham, I used Opus 5.5 in fast mode to implement Doom in Bel, @paulg's Lisp dialect, in about 20 minutes. 32,000 lines of C++ converted into fewer than 2,000 lines of Bel. Plus a complete Bel interpreter written in JS. Paul, time to vibe code!
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According to Tan, the model converted 32,000 lines of C++ into fewer than 2,000 lines of Bel. Bel is Paul Graham's Lisp dialect, which Tan used to implement Doom over dinner with its creator.
Porting between languages. Tan reported on Oct 6 that the work took about 20 minutes.
Along with the Doom code, the model wrote a complete Bel interpreter in JavaScript.
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