Bart wrote:
On 4/3/09, Jonas Maebe <jonas.ma...@elis.ugent.be> wrote:
I think what is meant, is that if you create a direct subclass of TObject,
there is no need to call TObject's create constructor (e.g., via "inherited
create;") from your own constructors. It doesn't hurt if you do it of
course, and may be good practice to account for future situations where the
parent class may change.
I often wondered abou that.
So if i understand correctly:
Say I have
Type
TFoo = class;
private
fSomeField: Integer;
public
constructor Create;
end;
then
constructor TFoo.Create
begin
Inherited Create;
fSomeField := -1;
end;
would in essence be equal to
constructor TFoo.Create
begin
fSomeField := -1;
end;
Since TOblect.Create "does nothing".
Essentially, yes.
However, you may create subtle, lurking bugs if you omit that call and
later refactor your code. For example, if you later change
type
TFoo = class
to
type
TFoo = class(TSomeClass)
and TSomeClass has some important work done in it's Create constructor.
If you properly called "inherited Create;" now that important stuff will
get done, just the way you want it to!
<emphasis>
So, the big lesson here is to stick to the proper structure even though
you may have outside knowledge that the form you should follow is not
strictly necessary in all cases.
</emphasis>
_______________________________________________
fpc-pascal maillist - fpc-pascal@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-pascal
