IndexLanguage (il)

A small, statically-typed language that transpiles to readable ES2022 JavaScript. The type system is TypeScript-flavored and gradual. The compiler is written in Rust and ships as WebAssembly.

See SPEC.md for the language reference.

fn fib(n: number): number {
  if n < 2 { return n; }
  return fib(n - 1) + fib(n - 2);
}

let i: number = 0;
while i < 10 {
  print("fib(" + i + ") = " + fib(i));
  i = i + 1;
}

Requirements

• Rust + wasm-pack (global install recommended)
• Bun or Node 18+

Build

bun run build        # wasm-pack, --target nodejs  -> pkg/
bun run build:web    # wasm-pack, --target web     -> examples/pkg/

Use

Node CLI

node examples/index.js examples/samples/fib.il        # print compiled JS
node examples/index.js run examples/samples/fib.il    # compile and execute
node examples/index.js --version

Browser playground

bun run build:web
bun run serve        # serves . ; open /examples/

Edit il source on the left, see the compiled JavaScript on the right, and click Compile & Run to execute it with output mirrored to the page.

Test

cargo test           # lexer / parser / checker / codegen unit tests

Compiler API

pkg/il_compiler.js exports:

• compile(src: string): string — returns generated JS, throws an Error whose message is the newline-separated diagnostics on failure.
• version(): string
• main(arg: string): void — legacy --help / --version / compile-and-log entry point