Ian's right.
ActionScript is a dynamic language with its own garbage collection, for
better or for worse. If you try to apply all the same practices and
rulesfrom strict-typed languages that requre manual memory management
you'll go
crazy. The best thing to do is to realize this type of languages strengths
and weaknesses and try to build on them. It's really up to the ActionScript
Virtual Machine now to do ALL memory management, along with your good
practices of making variables local when they can be local and dereferencing
them when you're done using them.
delete myObject;
by itself does not actually destroy myObject. Rather it dereferences the
variable name 'myObject' from the actual data. Later garabage collection
will take care of it if 'myObject' was the last reference to the data. Doing
a delete in this way on a local variable doesn't actually do anything, as
all local variables should clean on their own once their code block
finishes.
Tyler
On 5/3/06, Ian Thomas <[EMAIL PROTECTED]> wrote:
Um - I'm not sure it is beside the point. :-) Given that you are at
the mercy of the garbage collector, implementing a function like:
class MyClass
{
function cleanup()
{
delete _someProp;
delete _someOtherProp;
}
}
is pointless anyway, because if you delete an object of MyClass (or
rather _mark_ it for deletion by calling delete() - that's all
delete() does, and only then if there are no other references to the
class) then its properties are automatically marked for deletion.
Again, unless there are any other references.
The only time I've had to worry about destructors in a
garbage-collected language (such as Flash) is when dealing with
connections to resources - for example, connections to databases, or
closing open socket streams, or releasing handles to video memory
buffers, that sort of thing.
Those sort of things should be pretty rare in Flash... which is why I
asked what you're trying to achieve, because in most cases you can
find a way around it.
If you are dealing with some sort of resource that you want to make
sure shuts down properly when no-one is referring to it, one method is
to explicitly request/release access to the resource and implement
reference counting.
For example, here's a singleton resource class:
class MyResource
{
private static var _refCount:Number=0;
private static var _instance:MyResource;
public function MyResource()
{
}
public static function getResource():MyResource
{
if (_refCount==0)
{
_instance=new MyResource();
}
_refCount++;
return _instance;
}
public static function freeResource()
{
_refCount--;
if (refCount==0)
{
_instance.doCleanup();
_instance=null; // You could do delete here if you really wanted
to.
}
}
}
and then access it like so:
var res:MyResource=MyResource.getResource();
and when you're done
MyResource.freeResource();
But that's really long-winded, and breaks as soon as someone does this:
var res:MyResource=MyResource.getResource();
var res2:MyResource=res; // Took a copy
MyResource.freeResource();
res2.doSomething() // Breaks, because doCleanup() will have been called.
This sort of thing used to crop up quite a lot in C++; which is why
smart pointers and the like were invented.
I can't think of too many situations where you might need that sort of
thing in Flash; which is why I asked what you were trying to
achieve...
Ian
On 5/3/06, Andreas Rønning <[EMAIL PROTECTED]> wrote:
> Kind of besides the point really. The real point is, in my humble
> opinion, that it should be possible to do it without myClass.cleanup();
> delete(myClass);
> It becomes double naughty if your class instance is in an array.
> It's just a question of keeping the amount of fluff down to a minimum.
>
> This is not a critical problem. I am merely asking for people's
> methodologies in self destroying classes.
>
> - A
>
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