Xotcl February 2006

xotcl@alice.wu.ac.at

13 participants
13 discussions

Re: [Xotcl] Object destruction on exit
by Kristoffer Lawson 04 Feb '06

04 Feb '06

On 3 Feb 2006, at 17:11, Gustaf Neumann wrote: > Kristoffer Lawson schrieb: > >> >> Well this generally happens automatically anyway. If they are >> resources for which this does not happen, can we be sure that this >> is what the programmer wants? > > consitency is important. > in oo-systems, the programmer has a "contract" with the system, > that for every object > the life-cycle starts with the constructor and ends for the > destructors. > This is simlar to finalize() in java. > normally, you do not want to distinguish btwn. "manual" and > "automatic" destroys (which happen > btw. in various situations). I would say this depends very much on your point of view. In systems with prevalent persistence then the existence of an object continues until it is explicitly destroyed. Ie. automatic destruction does not occur. You can few objects in two different ways, as in-memory entities they exist only as long as the application exists. But you can also take the view that the in-memory entities are just representations of the actual object, which resides also on disc. > You cound do e.g. > > ::xotcl::Object setExitHandler {set ::xotcl::onEXIT 1} > > and check this variable from the destroy method whether or not the > db-instance > should be deleted. Yes, this could be one possible way round that. / http://www.fishpool.com/~setok/

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Ordering of Children
by Matthew Dodwell 03 Feb '06

03 Feb '06

Hi, Hopefully a simple question. I'm building a tree view controller and am seeing an unexpected ordering issue. I add with; MemoryLineController instproc init {} { my AddNode "File Diagnostics" my AddNode "Real time Diagnostics" my AddNode "Graphs" my AddNode "Post-Processing" } MemoryLineController instproc CreateTreeview {} { set counter 1 foreach childNode [my info children *gNode*] { $childNode BuildTreeNode [my tree] $counter incr counter } } MemoryLineController instproc AddNode {name} { eval GUINode [self]::[my autoname gNode%02d] -DisplayName {$name} } So the init method adds my root level nodes The order I get out is; Post-Processing File Diagnostics Real time Diagnostics Graphs i.e. the last is displayed first and then the next 3 in order. Why is this and what is the best way to correct it? thanks Matthew

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Object destruction on exit
by Kristoffer Lawson 03 Feb '06

03 Feb '06

When XOTcl exits, it seems that the [destroy] method is called on all objects. The first question is whether this is wise .. possibly. The problem is I would like to build a transparent layer for persistence storage which could be applied to a wide range of applications. The problem naturally is that the objects in the persistence storage get destroyed when the application exits :-) / http://www.fishpool.com/~setok/

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Xotcl February 2006