Beyond the Vibe, How far can we push It?
summary
Claim: a complete ECMAScript‑compliant JavaScript engine is built using AI agents and C# with ECMA-262 94,000 tests as the source of truth. Tools and pipelines include Codex/Claude agents, a supervisor test runner, a profiler front end for dotnet trace, and a Ralph loop evolved into factorial.ai that auto‑fixes backlog overnight. Architecture evolves from AST walking and CPS into IR lowering; results: runs real Express.js on .NET, about 93,500 passing and ~500 failing (regex lookbehind), and zero hand-written lines.
AI-written summary · about
chapters (18)
- 0:00Introduction
- 1:57Vague AI prompt for JS engine
- 4:50AI-generated runtime with tests
- 8:03AST walking and CPS transform
- 10:10Robust JavaScript runtime
- 14:02AI agents inspect running code
- 14:25Performance in runtime
- 17:17ECMA-262 knowledge gaps
- 20:5294,000 unit tests struggle
- 22:56Automated test runners
- 26:49Bad design via unsupervised agents
- 28:34Bizarre replay generator mode
- 31:45IR lowering refines architecture
- 32:48Live demo: Express.js on runtime
- 35:40100% JS language spec achieved
- 37:50Projects from JS engine journey
- 38:11Automated bug fixing with factorial.ai
- 38:57Q&A
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