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On 08/05/2011 12:41 AM, Chia-I Wu wrote:
> On Fri, Aug 5, 2011 at 1:48 PM, Chad Versace <c...@chad-versace.us> wrote:
>> On 08/04/2011 06:18 PM, Chad Versace wrote:
>>> On 08/04/2011 01:29 PM, Eric Anholt wrote:
>>>> On Thu, 4 Aug 2011 12:59:35 +0900, Chia-I Wu <olva...@gmail.com> wrote:
>>>>> From: Chia-I Wu <o...@lunarg.com>
>>>>>
>>>>> Unlike C++, empty declarations such as
>>>>>
>>>>> float;
>>>>>
>>>>> should be valid. The spec is not explicit about this actually.
>>>>>
>>>>> Some apps that generate their shader sources may rely on this. This was
>>>>> noted when porting one of them to Linux from Windows.
>>>>
>>>> Ew. Looking the GLSL 1.20 spec, I see:
>>>>
>>>> statement:
>>>> declaration_statement
>>>>
>>>> declaration_statement:
>>>> declaration
>>>>
>>>> declaration:
>>>> init_declarator_list SEMICOLON
>>>>
>>>> init_declarator_list:
>>>> single_declaration
>>>>
>>>> single_declaration:
>>>> fully_specified_type
>>>> fully_specified_type IDENTIFIER
>>>>
>>>> so it looks like that is actually valid code. That's awful.
>>>
>>> I first suspected that this was a spec grammar bug. But it is still present
>>> in
>>> the GLSL 4.10 spec, so it's unlikely to be a bug.
>>>
>>> Surprisingly, C also allows empty declarations. Compiling this
>>> float;
>>> int main() { return 0; }
>>> with `gcc --std=c99` succeeds and emits this warning:
>>> warning: useless type name in empty declaration [enabled by default]
>>>
>>> I hate to say this, but I believe the spec grammar intentionally allows
>>> empty
>>> declarations. C allows it, and GLSL tries to mimic C.
>>>
>>> Even though I don't like empty declarations, this patch is
>>> Reviewed-by: Chad Versace <c...@chad-versace.us>
>>
>> Also, please update the commit message to say that `gcc --std=c99` allows
>> empty
>> declrations and include the appropriate quotation from the GLSL 1.20 spec's
>> grammar. Without that extra info, someone may stumble onto this commit and
>> say WTF.
> Oops. I've already committed it...
You have to give a little more time for review. I would like to have
had an opportunity to weigh in, but it's a bit late now.
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