Propose small change to _Tobj to the Dacha man ;)
Thaddy © (2005-08-05 01:47:00)
This is an architectural matter.
What are your thoughts about this possible change to _Tobj
(The basic object for Tobj and therefore Tcontrol):
I propose to make the *first* field an untyped pointer, so
that you can assign other objects or data to it, just like
CustomObj and CustomData.
The advantage is, that you can typecast a full Tobj
descendant to the type that holds the pointer:
type
PPMyObject = ^PMyObject;
PMyObject = ^TMyObject;
TMyObject = object(Tobj)
....
end;
Now if the *first* field in _Tobj were a pointer, we could
assign a structure to it, say, PWaveFormatEx and we could typecast
the whole object as PPWaveFormatEx. Actually simulating interfaces
and /or "friend" in C++
You can already do this with simple objects, but you loose
the power of the destructor/free. (Add2Autofree, etc)
Right Now the first field is FRefCount. Ithink my proposal
would not break the code, only Frefcount and fTag need to be
switched?
Or am I missing something?
Thaddy (2005-08-05 02:01:00) [1]
And the typecast would be:
var
WaveFormat:TWaveFormatEx; // or any other record or
object
MyObject:PMyobject;
begin
MyObject:=NewMyObject;
MyObject.Tag:=Cardinal(@WaveFormat);// Assumes the
above!
PPWaveFormatEx(MyObject).nSamplesPerSec:=44100;
end;
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