[fpc-pascal] WriteComponent not outputting a hierarchy of components?

[Michael Van Canneyt]

On Thu, 3 Jun 2010, Graeme Geldenhuys wrote:

> On 3 June 2010 20:38, Michael Van Canneyt wrote:
>>
>> Because Borland decided otherwise.
>>
>> Actually, there is a good reason: some components create internal components
>> they own, and which they don't want to have streamed.
>> The 'GetChildren' allows you to control what gets streamed and what not.
>
> Well, isn't that what the 'stored' specifier could be used for too, to
> know if a property should be stored or not.

No, because there may not be a property. You can perfectly have a child
component without a property to access it.

> It just looks like a
> rather odd implementation (broken by default) for something that is so
> easily accomplished with a recursive procedure. All the required
> functionality (ComponentCount, Components[]) is already in place.

Once more, you need a way to distinguish between owned components
that must be streamed, and components that must not be streamed.
The 'Stored' modifier is not suitable because there may not be
a property to access the component. Plenty of examples around for 
that.

>> In LCL the owner is always the form. Otherwise the form variables
>> would not work.
>
> I know that, and the same think applies to VCL. But again, I don't see
> why Borland had to do that. Like fpGUI proves, it's not even required
> to have Owner and Parent. fpGUI can easily remove Parent and just use
> Owner and work perfectly. At the moment in fpGUI, Parent is just for
> convenience to VCL/LCL developers - it's just an alias for Owner.

Personally, I think that this is mixing 2 concepts:

Owner/Owned is a matter of lifetime and memory management of objects.
Parent/Child is a visual relationship.

They are separate concepts, and Borland decided to reflect this in the 
streaming system. (apart from the need to be able to exclude children from
being streamed).

I suppose there was a reason why they did this.
I once had a discussion about it with a Borland employee, and the way he made 
a point of it makes me believe there is a reason for it. We simply don't
know it.

Michael.