[DGD]kernel cloning and inheriting

[Erwin Harte]

On Wed, Feb 14, 2001 at 11:30:36PM -0500, Stephen Schmidt wrote:
> As I understand the source: In the kernel lib (version taken
> from DGD 1.2) any object may be cloned, or inherited, or
> neither, but not both. If it is in a directory with "lib" 
> in the path, it may be inherited but not cloned. If it is
> in a directory with "obj" (and not "lib") in the path, it
> may be cloned but not inherited. Otherwise it may be neither
> cloned nor inherited.
> 
> Why is that? I have a memory that it has something to do
> with updating code in cloned objects without rebooting;
> what are the details?

It has to do with practical limitations.  The compile_object() kfun
can be used to compile an already existing object in-place, but you
cannot re-compile an inherited object.

If you would allow an object to be cloned -and- inherited, this would
lead to situations where you are basically stuck: You cannot re-
compile the object because it is inherited, but you need to destruct
it, compile it, and re-compile (or destruct + compile) any objects
that in turn inherited the original object.

Of course, from a conceptual point of view it doesn't hurt to keep the
different 'types' of objects separated.

Erwin.
-- 
Erwin Harte         :    `Don't mind Erwin, he gets crabby. :)'
harte at xs4all.nl     :       -- Par Winzell <zell at skotos.net>

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