AW: [Xotcl] destroy invoked by object move?

Gustaf Neumann neumann at wu-wien.ac.at
Fri Mar 17 15:52:02 CET 2006


Scott Gargash schrieb:

> xotcl-bounces at alice.wu-wien.ac.at wrote on 03/15/2006 04:23:28 AM:
>
> >
> > On 15 Mar 2006, at 12:17, Gustaf Neumann wrote:
> > >
> >
> > I am actually quite surprised to find that the move operation calls  
> > the destructor. This is not mentioned on the reference manual and  
> > does, in fact, seem counter-intuitive. A move is a move, nothing is  
> > being destroyed, so why call the destructor?
>
> I agree.  A move operation didn't imply object destruction to me, either.
>
i would not expect this either, but it seems as a reasonable compomise. 
It has been
like this since implemented more than five years ago and has not caused 
any trouble.
maybe, it would have been better to provide only a copy operation, and 
delay move,
until it can be made properly in c with a namespace rename operations. 
anyhow,
for now, i have documented the copy+destroy operation in the manual.

>
> I'm guessing that xotcl::object's "destroy" method does all the heavy 
> lifting (cleaning up the source of the move).  What would happen if 
> the default move implementation was to change the source object's 
> class to xotcl::object before invoking destroy?  This way it would 
> continue to use the xotcl::object's "destroy" implementation for 
> cleanup purposes without invoking all of the subclass destroy methods, 
> and derived classes wouldn't perceive move as a destroy operation. 
>  Would this have bad side-effects?
>
for some applications, it might be the right things, for others not.

>
> While I'm no poweruser, I did get the guard mechanism to work.  Here 
> it is for completeness sake. (Is there an easy way to search the mail 
> archives?  Maybe this will help someone else...)
>
This qualifies you at least as a candidate for a power user :).
you might place this on the tcl wiki (http://mini.net/tcl/XOTcl)

mailman has no nice search interface, maybe we will switch at some time 
to something better....
best regards
-gustaf neumann



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