Add method to get the last line of a buffer

editor/editor.lisp

@@ -454,6 +454,11 @@ serial connection the editor normally runs under.")
         (buffer-view instance) (make-instance 'buffer-view :buffer instance)
         (top-line (buffer-view instance)) (first-line instance)))
 
+(defmethod last-line ((buffer buffer))
+  (loop :for line := (first-line buffer) :then (next-line buffer)
+        :until (null (next-line line))
+        :finally (return line)))
+
 (defmethod buffer-string ((buffer buffer))
   "Returns a string equivalent to BUFFER's contents."
   (with-output-to-string (output)