Installation

Weir uses Nix with flakes to manage all dependencies. This ensures a reproducible build environment regardless of your system.

Prerequisites

Install Nix with flakes enabled. If you don’t have Nix yet:

# Install Nix (multi-user recommended)
sh <(curl -L https://nixos.org/nix/install) --daemon

# Enable flakes (add to ~/.config/nix/nix.conf)
experimental-features = nix-command flakes

Clone and Enter

git clone <repo-url>
cd weirlang

Activate the development environment:

nix develop

This provides all build tools: Rust toolchain, Cranelift, libffi, pkg-config, and everything else needed to build the compiler.

Tip

If you use direnv, entering the project directory automatically activates the Nix environment — no manual nix develop needed.

Verify the Setup

Build the compiler and run all tests:

just test

You should see all tests pass (currently 647). You can also build the compiler directly:

just build

Available Commands

Run just to see all available recipes:

Command	Description
just build	Build all crates
just test	Run all tests
just check	Run clippy, check formatting, and run tests
just fmt	Format all code
just run <file>	Run a .weir file
just tetris	Build and run the OpenGL Tetris demo
just docs-dev	Start docs dev server
just docs-build	Build docs site

Editor Setup

Zed

A Zed extension is available at (TODO: Not published yet!) providing:

• Syntax highlighting via tree-sitter
• LSP integration (diagnostics, hover, completion, go-to-definition)

Other Editors

The Weir LSP server can be started with:

weir lsp

Any editor with LSP support can connect to it for diagnostics, completion, hover information, and navigation.