[DGD] Upgrading clones with changed internal representation

[Erwin Harte]

Noah Gibbs wrote:
>   Yup.  I got the impression that the Skotos patch stuff and call_touch would
> handle this, but I haven't checked that out to make sure it's true.  Maybe it
> keeps multiple versions around and you can have several active upgrade
> functions?

That would be nice, but as useful as call_touch() is, you can't use it to 
accomplish that kind of functionality.

>   Or maybe you just need to make sure that everything has been upgraded before
> you upgrade again.

Just make sure everything has been upgraded before you run that second 
upgrade/compile that permanently removes the variable(s) whose content you 
intend to transform somehow.

Calling call_touch() sets a flag for the object, doing that a second time 
before accessing the object doesn't accomplish anything useful that I'm aware of.

Erwin.