Field notes from building Sky Lang.
Sky's compiler was written in Haskell, and Haskell got it a very long way. Then one 24,000-line module, held together with global mutable state I spent a whole release trying to remove, told me the architecture had hit its ceiling. This is the story of the rewrite. Why Rust, why now, and the one decision that made replacing a working compiler feel safe rather than reckless.
"If it compiles, it works" is a slogan a dozen languages have used. In Sky Lang it's a contract — defined precisely, enforced by three release gates, and load-bearing for every decision the language makes. Here's what the contract says, how it's enforced, and the bug class that proved removing a single line of CSS can close five filed bugs.
Twelve weeks ago I started building a new language. Today it's at v0.15.55 with 1,232 commits, 35 examples, and 485 compiler specs. Here's the bet, the principles that held, and why I believe Sky Lang is the language AI builds production apps in.