On Wed, Oct 5, 2016 at 7:07 PM, Tony Whyman <tony.why...@mccallumwhyman.com> wrote: > >[...] > > No, if you explicitly free the provider class there will be no memleaks. My > point is that having to do this is counter-intuitive and easy to get wrong > - or to overlook cases where it is necessary.
That is it, counter-intuitive and easy to get wrong. Another thing easily to forget and get memleaks is not get the result of constructors. For example. Consider this: function TFoo.Execute(const Name: string): string; begin Result := TAction.Create(TTask.Create(Name)).Execute.ToString; end; - TTask is a class that takes a string in the constructor; - TTask implements ITask, an interface; - TAction is a class that receives an ITask interface in the constructor; - TAction implements IAction, an interface; - TAction has an Execute method that returns an IResult, an interface; - IResult has a ToString method that returns the result in string format; How many memory leaks we have here? 0, 1 or 2? The answer is 1. So, we need to declare an variable: function TFoo.Execute(const Name: string): string; var A: IAction; begin A := TAction.Create(TTask.Create(Name)); Result := A.Execute.ToString; end; Verbose and unnecessary, in my opinion. Sometimes I forget to declare a variable, sometimes not... this is unproductive! So, I created my own "design pattern" that I called: New Method. The refactored code is: function TFoo.Execute(const Name: string): string; begin Result := TAction.New(TTask.New(Name)).Execute.ToString; end; I explained here http://objectpascalprogramming.com/posts/interfaces-e-o-metodo-estatico-new/ but you need to translate. >> I understood you but I can't help, because I don't know how the >> compiler works to do this 'kind of magic' — I think only Object Pascal >> has delegation in that way, right? > > Here I was suggesting a compiler change (bug fix?) +1 >> Delegates is a powerful feature. I can write less and compose complexy >> objects using delegation. Really cool. >> >> We need to compare with Delphi? >> I don't have it, but I guess this problem there isn't there. > > I never used delegated interfaces in Delphi. In FPC I try to avoid them > given the problems you get. On the other hand, reference counted com > interfaces are a great feature and it's a pity delegated interfaces are so > awkward. I agree. Best regards, Marcos Douglas _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
