[llvm-dev] [cfe-dev] Modernizing LLVM Coding Style Guide and enforcing Clang-tidy

Sanjoy Das via llvm-dev llvm-dev at lists.llvm.org
Mon Jan 9 14:52:25 PST 2017


On Mon, Jan 9, 2017 at 10:31 AM, Piotr Padlewski via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
>
> 2017-01-09 19:25 GMT+01:00 Mehdi Amini <mehdi.amini at apple.com>:
>>
>>
>> On Jan 9, 2017, at 10:20 AM, Reid Kleckner via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>>
>> On Mon, Jan 9, 2017 at 7:25 AM, Piotr Padlewski via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>>>
>>> 2017-01-09 16:15 GMT+01:00 Renato Golin <renato.golin at linaro.org>:
>>>>
>>>> On 9 January 2017 at 14:17, Piotr Padlewski via cfe-dev
>>>> <cfe-dev at lists.llvm.org> wrote:
>>>> > - prefer "using' instead of "typedef"
>>>> > - use default member initialization
>>>> > - use default, override, delete
>>>> > - skip "virtual" with override
>>>>
>>>> I thought we had all of those already...
>>>>
>>> Nope, some people use it, but I still see a lot of new code with
>>> typedefs.
>>> I would like to have it written in style guide so it will be easier to
>>> convince to change in review.
>>
>>
>> The last two are enforced by compiler warnings now. The second is hard
>> because of bitfields.
>>
>> I object to the first. If you need a new type name, use a typedef. It's
>> time honored and everyone, including C programmers, will know what you're
>> doing. I don't understand why people push the new thing just for the sake of
>> new-ness.
>>
>>
>> `using` handles strictly more cases than  `typedef`, in particular partial
>> specialization of templates. So because we’ll end up with `using` anyway,
>> uniformity can be valuable. So that could be a motivation: since `using` is
>> needed anyway, might be better to just use it always (I’m not saying it is a
>> “strong” motivation though, just some piece of rational).
>> (I also find that typedef of function pointers in particular are terrible,
>> and `using` is much better for these, but that can be a matter of taste).
>>
>>>> Mehdi
>
>
> +1 Exactly this.
> I don't think C programmer will not understand using. The "=" makes it much
> simpler to read, even if it is the first time you see it, which is not the
> case of typedef.
>
> typedef MyType::NestedType (*fptr)(const MyOhterType&);
> or
> using fptr = MyType::NestedType (*)(const MyOhterType&);

I would prefer using typedefs at least for function pointers.  I find either of


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