rnix-parser 
rnix is a parser for the Nix language 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 Nix code. This demonstrates how whitespaces and commands are preserved.
RIP jd91mzm2
Sadly, the original author of this project, @jD91mZM2 has passed away. His online presence was anonymous and what we have left is his code. This is but one of his many repos that he contributed to.