An interpreter and compiler for the Monkey programming language written in Rust

https://monkey-lang-playground-jw.vercel.app/

https://astexplorer.net/#/gist/e23a81ce309e8fcffe95ddd1b5661061/01d0b4b078304ddd9639eae9f4e6d342e2b9d075

Monkey has a C-like syntax, supports variable bindings, prefix and infix operators, has first-class and higher-order functions, can handle closures with ease and has integers, booleans, arrays and hashes built-in.

• Split packages to make everything minimum
• REPL: A Read-Eval-Print-Loop (REPL) for Monkey tokenizer, parser, evaluator, compiler, and GC runtime
• location info for ast
• test for every module
• Wasm: A WebAssembly target, thus run monkey on browser is directly supported.
• Prettier Plugin: Format Monkey source code with Prettier via prettier-plugin-monkey.
• Minifier (@gengjiawen/monkey-minifier): A semantics-preserving source-to-source minifier powered by the Rust/Wasm parser, with compact printing, identifier mangling, constant folding and propagation, dead let elimination, and Node/browser/CLI APIs.
• VS Code Extension: First-class editor support with syntax highlighting, snippets, WASM-powered diagnostics, AST preview, and bytecode compilation commands.
• bytecode viewer from source
• GC (monkey-gc): alternate bytecode VM with QuickJS-style refcounting and three-phase cycle collection (gc_decref → gc_scan → gc_free_cycles) on a GcHeap, so cyclic object graphs can be reclaimed without changing object or the default Rc VM.
• Bytecode snapshots (.mbc): QuickJS-style ahead-of-time compilation, mirroring qjsc — monkey-gc compile foo.monkey serializes the compiled bytecode to a .mbc file and monkey-gc run foo.mbc executes it without the parser/compiler, treating the file as untrusted input behind a three-layer validation model (design doc).
• ASM (monkey-asm): AOT arm64 (AArch64) assembly backend — single-pass lowering from the AST to AArch64 assembly text, assembled and linked against a cross-built Rust runtime into a native executable, in Linux/ELF and macOS/Mach-O flavors (the Linux flavor runs on any host via qemu-aarch64); the playground's ARM64 tab shows the same assembly godbolt-style (design doc).

Official site is: https://monkeylang.org/. It's has various implementation languages :).

There is a book about learning how to make an interpreter: Writing An Interpreter In Go. This is where the Monkey programming language come from.