Ben Grasset <operato...@gmail.com> schrieb am Mi., 3. Juli 2019, 18:00:
> On Tue, Jul 2, 2019 at 7:38 PM Ondrej Pokorny <laza...@kluug.net> wrote:
>
>> A good real-word example is the cast from a pointer:
>>
>> program Project1;
>> uses Classes;
>> var
>> Value: TPersistent;
>> P: Pointer;
>> begin
>> P := TObject.Create;
>> Value := TPersistent(P);
>> if Value is TPersistent then
>> Writeln('Value is TPersistent')
>> else
>> Writeln('Value is not TPersistent');
>> Readln;
>> end.
>>
>
> In general, assuming P was a pointer initialized elsewhere (meaning you
> really didn't know what it was), why wouldn't you just write this:
>
> if TObject(P) is TPersistent then
> Writeln('Value is TPersistent')
> else
> Writeln('Value is not TPersistent');
> Readln;
>
> Behaves as you'd expect, and doesn't require an additional variable.
>
The code by Ondrej was to prove a point not to have the shortest variant.
Regards,
Sven
>
_______________________________________________
fpc-devel maillist - fpc-devel@lists.freepascal.org
https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
