Ah, I was wondering why the project was getting a few more eyes today! Maintainer here, I took over this excellent project from Tom Forbes in April 2023. He did a phenomenal job writing the parser and laying the groundwork for an interpreter. One of the beautiful things right now about this project is its simplicity — it’s tiny compared to cel-go for example. I’m also a huge fan of our Axum-style functions[1] where you can register pretty much any closure as a custom function to be used in your CEL expressions. There’s still some mileage to go to support some of the more obscure aspects of the spec, but I feel like we’re getting close, and we have an excellent little cadre of contributors that have been extremely helpful in moving this forward.

[1] https://github.com/clarkmcc/cel-rust/blob/master/example/src...