[Qt-creator] Using C++11 in Creator's source

Ziller Eike Eike.Ziller at digia.com
Tue Mar 25 12:24:15 CET 2014

On Mar 18, 2014, at 11:04 AM, Daniel Teske <daniel.teske at digia.com> wrote:

> On Tuesday 18 Mar 2014 09:44:17 Christian Kandeler wrote:
>> On 03/05/2014 11:12 AM, Poenitz Andre wrote:
>>> Ziller Eike wrote:
>>>> One rule for using “auto” that I’d like to establish, is to use it only
>>>> “when the type is obvious when reading the code”. Of course what that
>>>> exactly means should be discussed and shown in some examples, and then
>>>> it’s still up for interpretation. E.g.:
>>>> Yes:
>>>> auto f = new FooBar;
>>>> auto a = new A;
>>>> auto myAction = menu->addAction(…);
>>>> auto it = list.const_iterator();
>>>> No:
>>>> auto i = 4; // the difference between “4;” and “4.;” is subtile with big
>>>> consequences> 
>>> What is obvious for some might unfortunately not be so obvious for others.
>>>> From the list of "Yes" cases I only fully agree with "auto it =
>>>> list.const_iterator();">>
>>> I'd actually like to restrict the use of auto to cases where it
>>> "significantly" reduces typing and line noise (say, identifiers longer
>>> than x chars, and to cases where it doesn't change meaning.
>> On the other hand, patches that change types in function signatures will
>> potentially get much smaller if "auto" is used extensively. For
>> instance, if you take a look at the "QString -> Core::Id" or "QString ->
>> Utils::FileName" patches, you will notice that quite a number of hunks
>> would disappear entirely.
> But that's NOT a good thing. After all the type changed, the behavior changed, 
> and you need to look at all those places to consider the implications. 
> Utils::FIleName is a mostly drop in replacement for QString, but it behaves 
> differently.
>> In general, it seems to me that using "auto" is sensible when assigning
>> the result of a function call, as the type is already specified.
> The ultimate aim of our coding style is to make code maintainable, by being 
> readable.
> If you need to lookup the return values of functions, to understand code then 
> that makes the code less readable to me. The types of variables are important, 
> and thus shouldn't be hidden. 

I agree with Daniel.

Eike Ziller, Senior Software Engineer - Digia, Qt
Digia Germany GmbH, Rudower Chaussee 13, D-12489 Berlin
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