Function: treesit-subtree-stat

treesit-subtree-stat is a function defined in treesit.c.

Signature

(treesit-subtree-stat NODE)

Documentation

Return information about the subtree of NODE.

Return a list (MAX-DEPTH MAX-WIDTH COUNT), where MAX-DEPTH is the maximum depth of the subtree, MAX-WIDTH is the maximum number of direct children of nodes in the subtree, and COUNT is the number of nodes in the subtree, including NODE.

Other relevant functions are documented in the treesit group.

Shortdoc

;; treesit
(treesit-subtree-stat node)
    e.g. => (6 33 487)

Source Code

// Defined in /usr/src/emacs/src/treesit.c
{
  /* Having a limit on the depth to traverse doesn't have much impact
     on the time it takes, so I left that out.  */
  CHECK_TS_NODE (node);

  treesit_initialize ();

  TSTreeCursor cursor = ts_tree_cursor_new (XTS_NODE (node)->node);
  ptrdiff_t max_depth = 1;
  ptrdiff_t max_width = 0;
  ptrdiff_t count = 0;
  ptrdiff_t current_depth = 0;

  /* Traverse the subtree depth-first.  */
  while (true)
    {
      count++;

      /* Go down depth-first.  */
      while (ts_tree_cursor_goto_first_child (&cursor))
	{
	  current_depth++;
	  count++;
	  /* While we're at here, measure the number of siblings.  */
	  ptrdiff_t width_count = 1;
	  while (ts_tree_cursor_goto_next_sibling (&cursor))
	    width_count++;
	  max_width = max (max_width, width_count);
	  /* Go back to the first sibling.  */
	  treesit_assume_true (ts_tree_cursor_goto_parent (&cursor));
	  treesit_assume_true (ts_tree_cursor_goto_first_child (&cursor));
	}
      max_depth = max (max_depth, current_depth);

      /* Go to next sibling.  If there is no next sibling, go to
         parent's next sibling, and so on.  If there is no more
         parent, we've traversed the whole subtree, stop.  */
      while (!ts_tree_cursor_goto_next_sibling (&cursor))
	{
	  if (ts_tree_cursor_goto_parent (&cursor))
	    current_depth--;
	  else
	    {
	      ts_tree_cursor_delete (&cursor);
	      return list3 (make_fixnum (max_depth),
			    make_fixnum (max_width),
			    make_fixnum (count));
	    }
	}
    }
}