Zena
On this page

Getting Started

Early development

Zena has not been published to a package registry yet. For now, getting the toolchain means building it from the repository. This page will get much shorter once releases exist.

What you need ​

Zena compiles to WebAssembly GC, so you need a runtime that supports it:

  • Node.js 25 or newer — for the host target, via @zena-lang/runtime
  • wasmtime 24 or newer — for the wasi target
  • Any browser released since 2023, if you're shipping to the web

Install the toolchain ​

Clone the repository and build:

bash
git clone https://github.com/elematic/zena.git
cd zena
npm install
npm run build

That produces the CLI at target/release/zena-cli. Add a shell alias so the rest of these docs read the way they eventually will:

bash
alias zena="$(pwd)/target/release/zena-cli"

Nix users

The repository ships a flake with the full toolchain — Node, wasmtime, and wasm-tools. Run nix develop (or let direnv do it) and everything is on your PATH.

Create a project ​

A Zena project is a directory of .zena files. Start with one:

main.zena
export function main(): i32 {
  console.log('Hello from Zena!');
  return 0;
}

Zena has no globals, so even console is imported. Every name in a file is either declared there or imported into it.

Build and run ​

zena run compiles and executes in one step:

bash
zena run main.zena
text
Hello from Zena!

To keep the module around, build it:

bash
zena build main.zena -o main.wasm

Pick the target that matches where the module will run:

host
bash
# Core Wasm GC with console imports, for @zena-lang/runtime and the browser
zena build main.zena -o main.wasm --target host
wasi
bash
# Core Wasm GC with WASI imports, for wasmtime and jco
zena build main.zena -o main.wasm --target wasi
wasmtime main.wasm

Type-check without emitting anything — this is the fast inner loop:

bash
zena check main.zena

Editor setup ​

The repository includes a VS Code extension with syntax highlighting and language-server integration:

bash
code --install-extension packages/vscode-zena

See Editor support for other editors and for running the language server directly.

Next steps ​