Extra credit...

Here is a small augmentation of the PATH-BETWEEN that does pop up the  
highlighted text of the function when you double-click in the graph  
pane:

(defun view-tree (tree from to)
   (when tree
     (capi:contain
      (make-instance
       'capi:graph-pane
       :title (format nil "Path from ~A to ~A"
                      (display-form from) (display-form to))
       :roots (list tree)
       :children-function #'node-children
       :print-function    #'(lambda (node)
                              (format nil "~A" (display-form (node- 
parent node))))
       :edge-pinboard-class 'capi:arrow-pinboard-object
       :interaction :single-selection
       :action-callback  'graph-pane-action-callback
       )
      :best-width 400
      :best-height 300)))

(defun graph-pane-action-callback (node intf)
   (declare (ignore intf))
   (let* ((df     (display-form (node-parent node)))
          (locs   (dspec:find-dspec-locations df))
          (toploc (cadr (car locs))))
     (print locs)
     (when (pathnamep toploc)
       (ed df) )))


Dr. David McClain
dbm@refined-audiometrics.com