rnix

rnix is a Nix parser written in Rust.

This can be used to manipulate the Nix AST and can for example be used for:

• Interactively render Nix on a GUI
• Formatting Nix code
• Rename identifiers

and a lot more!

rnix nowadays uses @matklad's rowan crate to ensure:

• all span information is preserved, meaning you can use the AST to for example apply highlighting
• printing out the AST prints out 100% the original code. This is not an over-exaggeration, even completely invalid nix code such as this README can be intact after a parsing session (though the AST will mark errnous nodes)
• easy ways to walk the tree without resorting to recursion

Demo

Examples can be found in the examples/ directory.

You may also want to see nix-explorer: An example that highlights AST nodes in valid Nix code. This demonstrates how span information is preserved.