jichu4n / quo

Toy self-hosted language that compiles to WebAssembly

Quo

Quo is a toy language with C-style syntax that compiles to WebAssembly. It is bootstrapped with a minimal version of the compiler implemented in hand-written WebAssembly. Each subsequent iteration of the compiler is written in the subset of the language supported by the previous iteration, and provides additional language features for the next iteration.

Why?

Because it's a fun challenge! I've always been interested in compilers and wanted to learn more about WebAssembly. There's just something very cool about bootstrapping a self-hosted compiler.

Iterations

• Stage 0 (quo0.wat): Written in WebAssembly, compiles a minimal version of Quo (Quo0) in which stage 1 compiler is written.
  • Single pass, no AST / IR
  • Minimal Turing complete syntax
  • Only data type is i32
  • Uses linear memory with no memory management
• Stage 1 (quo1.quo): Written in Quo0, compiles Quo0. Effectively a translation of the stage 0 compiler into Quo0 itself, with no additional language features added.
  • quo1a.wasm: stage 1 compiler compiled by stage 0 compiler
  • quo1b.wasm: stage 1 compiler compiled by quo1a.wasm
  • quo1c.wasm: stage 1 compiler compiled by quo1b.wasm, i.e. a fully self-hosted compiler!
  • Includes runtime providing some basic runtime functions:
    • Memory management with malloc / free
    • Data structures including dynamic strings, arrays and maps
• (WIP) Stage 2 (quo2.quo): Written in Quo0, compiles a more advanced version of Quo (Quo1) supporting structs.