Minor

protocol.lisp

@@ -529,7 +529,7 @@
       (declare (dynamic-extent #'consider))
       (call-with-overlapping #'consider container region))))
 
-(defun describe-tree (node children-fun stream &key (max-depth (or *print-level* 3)))
+(defun describe-tree (node children-fun stream &key (max-depth (or *print-level* 3)) (key #'identity))
   (fresh-line stream)
   (labels ((recurse (node last depth)
              (when last
@@ -538,7 +538,7 @@
                    (format stream "~:[│  ~;   ~]" p))
                  (format stream "~:[├~;└~]─" cur)))
              (cond ((< depth max-depth)
-                    (format stream " ~a~%" node)
+                    (format stream " ~a~%" (funcall key node))
                     (let ((children (funcall children-fun node)))
                       (when (typep children 'sequence)
                         (loop with max = (1- (length children))