Vibe-coding a debugger for a DSL

Earlier this week a colleague of mine, Emilio Jesús Gallego Arias, shared a demo of something he built as an experiment, and I felt the desire to share this and add a bit of reflection. (Not keen on watching a 5 min video? Read on below.) What was that? So what did you just see (or skipped watching)? You could see Emilio’s screen, running VSCode and editing a Lean file. He designed a small…