AW: [Xotcl] destroy invoked by object move?

[Gustaf Neumann]

Scott Gargash schrieb:
>
> xotcl-bounces at alice.wu-wien.ac.at wrote on 03/19/2006 05:32:31 AM:
>
> >
> > On 19 Mar 2006, at 14:09, Scott Gargash wrote:
> >
> > > xotcl-bounces at alice.wu-wien.ac.at wrote on 03/19/2006 04:08:40 AM:
> > >
> > > >
> > > > On 19 Mar 2006, at 00:12, Scott Gargash wrote:
> > > > >
> > > > > When would you need the namespace of the object?
> > > > I have only ever needed the namespace of an object which attaching
> > > > traces to variables (f.ex. with Tk), but for that it is,
> > > > unfortunately quite necessary.
> > >
> > > I haven't used it yet, but doesn't the "trace" method handle this?
> >
> > No. Some tk widgets map their values to Tcl variables. Other similar  
> > interfaces exist. It is handy to map them to an instance variable but  
> > for that it is necessary to have the namespaced version available.
>
> Snit has a "myvar" method that returns the fully qualified name of a 
> snit member variable.  Perhaps something similiar (a method that 
> returned a "reference" to an instance variable) would be useful in 
> XOTcl?  
>
well, without trying it out. variable_reference could look like:

Object instproc variable_reference name {
   my requireNamespace
   return [self]::$name
}

in many situations, these fully qualified variable references are not 
needed,
since e.g. the forwarder allows variable names to be used in scope of an
object, such that e.g.

  obj set x 100
  obj lappend y 1 2 3

does the right thing (interpret variable references x and y in the obj 
scope),
no matter whether obj has a object-specific  namespace or not. It would
be rather painful to write

   obj lappend [obj variable_reference y] 1 2 3

These forwarders are registered during startup via:

foreach cmd {array append lappend trace eval unset} {
  ::xotcl::Object instforward $cmd -objscope
}

-gustaf neumann