RustChap

RustChap teaches the Rust programming language the way Euclidea teaches geometry: through small puzzles with exact answers. You do not type code on a phone keyboard. You tap tokens, reorder statements, and pick the best implementation. Every possible answer was compiled ahead of time with the real Rust compiler, so every verdict - compile error, test failure, or optimal solution - is the compiler's truth, not a quiz author's opinion. - 15 decks following one arc: ownership, borrowing, lifetimes, slices, Option and Result, pattern matching, iterators, closures, traits, generics, smart pointers, interior mutability, API design, async, and unsafe. - More than 60 puzzles, each teaching exactly one instinct. Match the star budget - like 0 clones in 2 edits - to earn the Optimal rank. - 20 short lectures in plain English. Every deck opens with one. - An AI tutor that knows the puzzle you are looking at. It runs on your device by default; nothing leaves your phone. Optionally use your own OpenRouter key for a cloud model. - Fully offline. No account, no ads, no tracking, no server. Built for experienced programmers who want Rust to feel like instinct. From Uncle Code, author of Crawl4AI. Built while skilling up for a Rust rewrite, inspired by many playthroughs of Euclidea. The full source is public at github.com/unclecode/rustchap - contributions welcome. RustChap is an independent educational app. It is not affiliated with or endorsed by the Rust Foundation. Ferris artwork by Karen Rustad Tolva (CC0).