Currently this code:
type
T1 = class
public
FStat: Integer; static;
end;
T2 = class(T1);
begin
T1.FStat := 5;
T2.FStat := 6;
Writeln(T1.FStat, T2.FStat);
end.Outputs '66'. That is (I think) as designed, but is IMO unfortunate ;-) I'd like to propose a language extension where
adding 'virtual' modifier to a static field declaration, like this:
FStat: Integer; static; virtual;Creates one instance of the variable per class, including derived classes. To implement it, compiler might either reserve a VMT slot for a pointer to the variable instance or just assign a fixed offset from the VMT.
This would be very useful, for example, when creating object persistency frameworks. Currently to associate a unique data instance with every class I have to create a global hash table using class name as a key -- clearly not optimal solution.
Alexander S. Klenin
Insight Experts Ltd.