VTP path questions

[Guido.Bosch@loria.fr (Guido Bosch)]

I've some questions about VTP paths and selections.

Having the root tree of a ctview, and having selected a subtree (with
the mouse) in that same ctview:

1. How can I get the selected subtree?

2. How can I get the path to that subtree with respect to the
   root tree?

3. I would like to keep a permanent description of this path in order
   to find again the subtree, even if it is no longer selected (e.g.,
   after having stored and reloaded the root tree in an other
   session). What I need is a good format to define such a storable
   and lisp-readable path description, say {path-description}, and the
   following two functions working on it:

   
   get-path-description: ROOT x SUBTREE -> PATH-D
	Returns the path description PATH-D  that describes the
	position of SUBTREE with respect to ROOT.
	
   get-subtree: 	 ROOT x PATH-D  -> SUBTREE
	Returns the subtree  SUBTREE of ROOT, according to the 
	path description  PATH-D.

	where root, subtree: {tree}
	      path-d: {path-description}



Seems to be a rather standard VTP hacks, but I'm a VTP novice.


	Guido