We have an intention to write our own treesitter parser for Darklang, abandoning our intermediate use and wrapping of the F# parser. We started in April 2023, with progress here. That said, our grammar is super thin right now, we haven't worked out bindings to .NET/F#, and we’ve only recently (Oct 2023) started to reason about how the parser will play within our editor (currently a VS Code extension powered by an LSP server).