X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/294127e7d59a5d23a32561716a1b192db410e12f..3ef311678b1467d6e6852cbc509fb92917f6f449:/lisp/dom.el

diff --git a/lisp/dom.el b/lisp/dom.el
index 11357e8880..091197a8f9 100644
--- a/lisp/dom.el
+++ b/lisp/dom.el
@@ -25,6 +25,7 @@
 ;;; Code:
 
 (require 'cl-lib)
+(eval-when-compile (require 'subr-x))
 
 (defsubst dom-tag (node)
   "Return the NODE tag."
@@ -149,6 +150,16 @@ ATTRIBUTE would typically be `class', `id' or the like."
 	  (setq result (dom-parent elem node))))
       result)))
 
+(defun dom-previous-sibling (dom node)
+  (when-let (parent (dom-parent dom node))
+    (let ((siblings (dom-children parent))
+	  (previous nil))
+      (while siblings
+	(when (eq (cadr siblings) node)
+	  (setq previous (car siblings)))
+	(pop siblings))
+      previous)))
+
 (defun dom-node (tag &optional attributes &rest children)
   "Return a DOM node with TAG and ATTRIBUTES."
   (if children