[Xotcl] Deleting objects

[MichaelL at frogware.com]

Look at the following code, which is meant to be a stripped-down and 
simplified version of my real code:

Class DatabaseMgr

DatabaseMgr instproc openDatabase {} {
    Database [self]::db
}

Class Database

Database instproc init {} {
    puts "init [self]"
}

Database instproc destroy {} {
    puts "destroy [self]"
}

DatabaseMgr dbmgr

dbmgr openDatabase

dbmgr::db info class
dbmgr::db destroy
dbmgr::db info class

The second call to "info class" should fail but doesn't. That's because 
the object isn't actually destroyed. (In my real code the objects have 
dynamically generated names; I used the static names to simplify the 
example.)

The above style is similar to the style of code used in xoRBAC (eg, 
factories & self-destruction) so I'd be surprised if it too wasn't leaking 
objects.

After the above code run this code:

dbmgr info class
dbmgr destroy
dbmgr info class

Now both dbmgr and dbmgr::db are destroyed--but note that the "destructor" 
gets called twice at this point!

By contrast, the following example (which also uses nested/aggregated 
objects) succeeds (which is to say that the second call to "info class" 
fails):

Object instproc doSomethingAndDie {} {[self] destroy}
set xxx [Object new]
set yyy [Object new -childof $xxx]
set zzz [Object new -childof $yyy]
puts "[$yyy info class]"
$yyy doSomethingAndDie
puts "[$yyy info class]"
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://alice.wu-wien.ac.at/pipermail/xotcl/attachments/20030512/084080bc/attachment.html