[Xotcl] Linking object instance variables to a widget -textvariable?

[Catherine Letondal]

Uwe Zdun wrote:
> Hi Ken,
> 
> perhaps others use other styles, but a simple way to bind variables,commands,
       
> or other callbacks from TK into XOTcl is replacement of "self" (or "my") from
       
> within a XOTcl method. Example:
> 
> Class BrowserTree
> BrowserTree instproc init args {
>    ...
>    set tree  [Tree $sw.tree \
>                    -relief flat -borderwidth 0 -width 15 -highlightthickness 
> 0\
> 		   -redraw 0 -dropenabled 1 -dragenabled 1 \
>                    -dragevent 3 \
>                    -droptypes {
>                        TREE_NODE    {copy {} move {} link {}}
>                        LISTBOX_ITEM {copy {} move {} link {}}
>                    } \
>                    -opencmd   "[self] modifyTree 1 $sw.tree" \
>                    -closecmd  "[self] modifyTree 0 $sw.tree"]
>     ...
>     $tree bindText  <ButtonPress-1>        "[self] selectTreeElement $tree"
>     $tree bindText  <Double-ButtonPress-1> "[self] openTreeElement $tree"
>     ...
> }
> 
> note that you cannot use curly brackets {} here, because then self would 
> not be replaced within the object's scope and would likely have a wrong value
> or raise an exception.
> 
> this style of binding works nicely together with XOTcl's inheritance and 
> mixins
> 

This work perfectly for commands, and I use it all the time, but it does not
work for variables.
In fact, I believe Tk always expect a Tcl global variable and an XOtcl 
object instance variable is not a global variable, right?

So the issue is maybe : how to bind an Xotcl object instance variable
to a Tcl global variable?

Catherine