Friday 24 November 2023

How to write try finally blocks

 I recently came across code another developer had done and they write try..finally blocks like the following:

procedure TSomeClass.DoSomething: string;
var
    myClass: TMyClass;
begin
    myClass := nil;
    try
        myClass := TMyClass.Create;
        // Do stuff
    finally
        myClass.Free;
    end;
end;

Were I would write it as follows:

procedure TSomeClass.DoSomething: string;
var
    myClass: TMyClass;
begin
    myClass := TMyClass.Create;
    try
        // Do stuff
    finally
        myClass.Free;
    end;
end;

I always create the object on the line before the try and would not set the object to nil just before creating it. I believe setting the object to nil before creating it and putting the create after the try to not be the correct way and do not know the reasoning why the developer does it like this.