[fpc-pascal] Re: Duplicate Identifier

[Sven Barth]

On 01.03.2012 21:42, Marcos Douglas wrote:
> On Thu, Mar 1, 2012 at 5:14 PM, Sven Barth<pascaldragon at googlemail.com>  wrote:
>> On 01.03.2012 16:34, Marcos Douglas wrote:
>>>
>>> On Thu, Mar 1, 2012 at 4:29 AM, leledumbo<leledumbo_cool at yahoo.co.id>
>>>   wrote:
>>>>
>>>> That's different case IMHO (In My Humble Observation), I guess it's
>>>> something
>>>> like this:
>>>>
>>>> {$mode objfpc}
>>>> type
>>>>   TTestClass = class
>>>>     FTile: Integer;
>>>>     property Tile: Integer read FTile write FTile;
>>>>     procedure Test;
>>>>   end;
>>>>
>>>> procedure TTestClass.Test;
>>>> var
>>>>   Tile: Integer;
>>>> begin
>>>> end;
>>>>
>>>> begin
>>>> end.
>>>>
>>>> In this case, the local variable has the same name as one of the class
>>>> properties. This does trigger the "duplicate identifier" error because
>>>> both
>>>> have the same scope.
>>>
>>>
>>> Well, for me the local Tile variable should have "preference" because
>>> the scope is local, not "global for class".
>>> Would be equal the use of arguments, IMHO, where we can use an
>>> identifier that already exists in the class.
>>
>>
>> In mode Delphi this is true, but in non-Delphi modes it was decided that the
>> above code is not allowed at all to avoid any disambiguities that might
>> arise.
>>
>> Regards,
>> Sven
>
> So, I have to invent a prefix or suffix in all local variables to
> avoid problems if I add a property with same name in the future,
> right?
> ex:
>    lTile: Integer
>    Tile1: Integer
>    vTile: Integer
>
> ...well, I already do that, but I don't think this is correct.

The compiler will generate an error if you do add a property with the 
same name, so you can change the name of the variable in the method on 
demand.

Also note that this feature is not a recent one. This is part of FPC 
AFAIK at least since 2.2.0 (which is the first version I used). So if 
you didn't encounter the problem yet, maybe you never will ;)

Regards,
Sven