How to get the field name of a node

[meain]

I was wondering if there was a way to get the field name of a node. I am not sure if I using the correct terminology, but I was wondering if I can give the type_identifier node and get something like :type or "type" out of it? I am aware of tsc-get-child-by-field, but I wanted to lookup the field name if any for a specific node. I was not able to find anything in the elisp files or follow this function.

Something with the signature Node -> Optional<Field>

[ubolonton]

There is currently no API to get a node's field name under its parent node. As a workaround, you can use this implementation (it's a bit convoluted, and not as efficient as a Rust implementation could be):

(defun tsc-node-field (node)
  (when-let* ((parent (tsc-get-parent node))
              (cursor (tsc-make-cursor parent))
              (_  (tsc-goto-first-child cursor))
              (child (tsc-current-node cursor)))
    (while (and child (not (tsc-node-eq child node)))
      (setq child (if (tsc-goto-next-sibling cursor)
                      (tsc-current-node cursor)
                    nil)))
    (tsc-current-field cursor)))

What is your specific use case, though?

[meain]

To be frank, I was just playing around with the debug-mode and trying to add some more info onto it. I was thinking about a info panel via popups or in modeline which would have this when I am on a node in the code.

Btw, is the rust interaction with the elisp part documented anywhere. Where should I be looking into if I were to add something like this into the rust code?

[ubolonton]

To be frank, I was just playing around with the debug-mode and trying to add some more info onto it. I was thinking about a info panel via popups or in modeline which would have this when I am on a node in the code.

That sounds pretty useful!

Btw, is the rust interaction with the elisp part documented anywhere. Where should I be looking into if I were to add something like this into the rust code?

Basically you would write a new Rust function and mark it with #[defun] so that it's callable from Lisp. The Rust code for node APIs are in core/src/node.rs. You can check out emacs-module-rs doc for more details.