[DUG] Dumb Friday Question

[Neven MacEwan]

Hi

The solution is to use interfaces, but if you don't it would be 
difficult to implement a factory pattern
There is this thing in OO language users which seems to be the muddy 
area between scalars and objects,
ie is a TStringList a simple object or a complex scalar, of course it 
doesn't help that Delphi garbage collects scalars
but not objects

Maybe i've been writing to much PHP

Neven




>> You guys don't consider a constructor a function then?
>>
>> I think its totally stylistic, if you want to have functions returning 
>> objects fine, just make it plain that they do,
>>
>> IMHO
>>
>> Neven
>>     
>
> The downside to having "creator function"s returning objects is that you
> have to duplicate the code in TObject.Create to ensure safety, as Struan
> pointed out.
>
> // Regular usage: constructor code guarantees no memory leak possibility
>
>   MyObject := TMyObject.Create;
>   try
>     ...
>   finally
>     MyObject.Free;
>   end;
>
> Replace TMyObject.Create with a creator function and you have to implement
> its safety code again yourself:
>
> // Function returning constructed object requires try/except to be safe
>
>   function CreateMyObject: TMyObject;
>   begin
>     ...
>     Result := TMyObject.Create;
>     try
> {
> Any code you might put in here requires this encompassing try/except block
> to prevent a memory leak occurring if an exception occurs
> }
>     except
>       Result.Free;
>       raise;
>     end; 
>   end;
>
>
> And the same again for any additional levels of nesting. Not great from the
> POV of encapsulation.
>
> Cheers,
> Carl
>
>
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