CENTAUR

[durrieu@tls-cs.cert.fr (Guy Durrieu)]

I got an error which is not very clear for me.

In a program transformation algorithm, I replace a subtree by another subtree,
which in this case simply was a *copy of the first subtree*, a singleton:

((((colon 0 singleton) (#[transe 0 ((((comment_s * ((COMMENT ((meta 0 
metavariable) (#[transe 0 ((((comment_s * ((COMMENT ((meta 0 metavariable) (#[
transe 0 ((((comment_s * ((COMMENT ((meta 0 metavariable) (#[transe 0 ((((
comment_s * ((COMMENT ((meta 0 metavariable) (#[transe 0 ((((comment_s * ((
COMMENT ((meta 0 metavariable) (#[transe 0 ((((comment_s * ((COMMENT ((meta...

The exception raised is the following:

** toplevel : undefined escape : (abstract_syntax (1 appartient ((((colon 0 
singleton) (#[transe 0 ((((comment_s * ((COMMENT ((meta 0 metavariable) (#[
transe 0 ((((comment_s * ((COMMENT ((meta 0 metavariable) (#[transe 0 ((((
comment_s * ((COMMENT ((meta 0 metavariable) (#[transe 0 ((((comment_s * ((
COMMENT ((meta 0 metavariable) (#[transe 0 ((((comment_s * ((COMMENT ((meta...
= ()

what happens?

Another question: is it possible to implement some kind of "unwinding" menu,
that is, a menu the buttons of which open other menus..? I have many things to
put in my menus.

                                            Thanks for your help.
                                                Guy DURRIEU.