Add function to sort lines by length.

configs/init-functions.el

@@ -88,7 +88,9 @@ If PROJECT is not specified, assume current project root."
 ;; Renombrar el archivo actual
 (defun rename-this-file (new-name)
   "Renames both current buffer and file it's visiting to NEW-NAME."
-  (interactive "sNew name: ")
+  (interactive (list (read-string "New name: "
+                                  (file-name-nondirectory
+                                   (buffer-file-name)))))
   (let ((name (buffer-name))
         (filename (buffer-file-name)))
     (unless filename
@@ -135,5 +137,19 @@ If PROJECT is not specified, assume current project root."
   (interactive)
   (insert (file-name-nondirectory (buffer-file-name))))
 
+(defun sort-lines-by-length (reverse beg end)
+  "Sort lines by length."
+  (interactive "P\nr")
+  (save-excursion
+    (save-restriction
+      (narrow-to-region beg end)
+      (goto-char (point-min))
+      (let ;; To make `end-of-line' and etc. to ignore fields.
+          ((inhibit-field-text-motion t))
+        (sort-subr reverse 'forward-line 'end-of-line nil nil
+                   (lambda (l1 l2)
+                     (apply #'< (mapcar (lambda (range) (- (cdr range) (car range)))
+                                        (list l1 l2)))))))))
+
 (provide 'init-functions)
 ;;; init-functions.el ends here.