[fpc-pascal] Re: Duplicate Identifier

[Sven Barth]

Am 02.03.2012 13:23, schrieb Marcos Douglas:
> On Thu, Mar 1, 2012 at 5:49 PM, Sven Barth<pascaldragon at googlemail.com>  wrote:
>> 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.
>
> But if I have many methods with a identifier like Value, I will have
> to modify all methods and put something like lValue, Value1, etc.

If the methods belong to a class where you introdouced a "Value" field 
or property, yes, you'll either need to change the variable/parameter of 
the method or choose a different name for the field/property.

>> 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 ;)
>
> I had problems. I use FPC 2.6. Because that problems I'm using such
> abstract prefix in all local variables..  =|

As I said: this feature is older than my first usage of FPC. So you'll 
have to life with it as we all need to (yes, I would know how to disable 
it and no, I don't want to). If you want to use ambitious naming then 
use mode Delphi.

Regards,
Sven