[Lazarus] Example requested for TList and Sort using data type of Object (or record).

[Marcos Douglas]

On Wed, May 11, 2011 at 9:35 AM, Sven Barth <pascaldragon at googlemail.com> wrote:
> Am 11.05.2011 14:30, schrieb Marcos Douglas:
>>
>> On Wed, May 11, 2011 at 3:51 AM, Mattias Gaertner
>> <nc-gaertnma at netcologne.de>  wrote:
>>>
>>> function SortComponentsForName(Item1, Item2: Pointer): integer;
>>> var
>>>  Comp1: TComponent absolute Item1;
>>>  Comp2: TComponent absolute Item2;
>>> begin
>>>  Result:=CompareText(Comp1.Name,Comp2.Name);
>>> end;
>>
>> I did not know about 'absolute' yet... what is the vantage?
>> Can you give me a link about it, please?
>
> See here (in the list point 6):
> http://freepascal.org/docs-html/ref/refse20.html#x52-590004.2
>
> It allows you to declare a variable that has the same location as another
> variable or parameter (but it does not need to have the same type). In the
> example written by Matthias Comp1 contains the value of Item1 from the
> "begin" on. The other way to achive this is the following:
>
> function SortComponentsForName(Item1, Item2: Pointer): Integer;
> var
>  Comp1, Comp2: TComponent;
> begin
>  Comp1 := TComponent(Item1);
>  Comp2 := TComponent(Item2);
>  Result := CompareText(Comp1.Name, Comp2.Name);
> end;

OK... and an Exception occur if the conversion fail?
I always use the other way, ie, type-conversion... but thanks.

Marcos Douglas