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List:       sssd-devel
Subject:    Re: [SSSD] Code style -- for loop iterative variables initial declaration
From:       Michal Židek <mzidek () redhat ! com>
Date:       2015-08-31 11:24:17
Message-ID: 55E43961.6030106 () redhat ! com
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On 08/31/2015 01:20 PM, Jakub Hrozek wrote:
> On Mon, Aug 31, 2015 at 02:09:19PM +0300, Alexander Bokovoy wrote:
>> On Mon, 31 Aug 2015, Lukas Slebodnik wrote:
>>> On (29/08/15 14:33), Alexander Bokovoy wrote:
>>>> On Fri, 28 Aug 2015, Petr Cech wrote:
>>>>> Hi everyone,
>>>>>
>>>>> I would like to ask you what you think about the initialization of
>>>>> iterative variables in forloops. I know that present code style does not
>>>>> allow it. But how I recognized, we use C99, and this feature is here now.
>>>>>
>>>>> (example)
>>>>> Instead of:|
>>>>> |||# inti;
>>>>> # for(i =0;...)|||
>>>>> we could write:
>>>>> ||# for(inti =0;...)|
>>>>>
>>>>> I see an advantage in limiting the validity of such variables. That means
>>>>> higher code readability. Disadvantages I searched but did not find.
>>>> What this misses is a use case of indexed searches where resulting index
>>>> value is used beyond the loop itself. By changing context of variable
>>>> declaration, you make variable inaccessible outside of the loop.
>>>>
>>> I would say it's exactly the purpose of this proposal.
>>> To decrease scope of visibility so the index variable with short name
>>> cannot be misused for different purpose.
>> Huh? There are valid cases where you search for an element and then use
>> it further in the code. The index is what you get as the result of the
>> search, not a reference to the element. Sometimes you need an element's
>> reference but in many cases you need an index.
>>
>> Reducing scope is fine if you understand the context but claiming
>> 'misuse' is a bit too much here.
>>
>> I'd suggest adding this syntax recommendation to SSSD C coding style
>> guidelines but add as well a bit of explanation on these two types of
>> loop usage patterns.
>
> Then I would suggest not to use the generic "i" name, but a more
> descriptive one for the variable.
>
> On a related note -- Michal, any progress on updating the code
> guidelines?

Yes, but I would prefer to update the coding guidelines after
Petr finish the wiki refactoring, so that I will not be adding
stuff under his nose.

Michal

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