[Development] Proposing changes to https://wiki.qt.io/Qt_Coding_Style

[Marc Mutz]

On 09.05.23 22:15, Allan Sandfeld Jensen wrote:
> On Dienstag, 9. Mai 2023 08:51:37 CEST Marc Mutz via Development wrote:
[...]
>> - space after template and before <:
>>
>>     // WRONG
>>     template<class T>
>>     // CORRECT:
>>     template <class T>
>>
> 
>> Rationale: We always used the latter in Qt.
> 
> We have always used both. I prefer the first one, which also happens to be the
> default by old Qt styles, but the second one is now more common in QtCore.

Some historical data, mined using

     $ git grep --recurse-submodules -e 'template <' $version -- | \
        grep -v /3rdparty/ | wc -l
     $ git grep --recurse-submodules -e 'template<' $version -- | \
        grep -v /3rdparty/ | wc -l

     Qt   | template < | template< | remarks           |
     -----+------------+-----------+-------------------+
     4.5  | 2037       |  606      | qt.git            |
     4.8  | 2440       |  796      |                   |
     -----+------------+-----------+-------------------+
     5.0  | 2479       | 1429      | qt5.git (beta-1)  |
     5.6  | 3103       | 2040      |                   |
     5.9  | 3315       | 2103      |                   |
     -----+------------+-----------+-------------------+
       (_clang-format demanding template< added here)  |
       (existed before in qtrepotools, it seems)       |
     -----+------------+-----------+-------------------+
     5.12 | 5051       | 2637      |                   |
     5.15 | 4989       | 2838      |                   |
     6.0  | 5353       | 4027      |                   |
     6.2  | 5580       | 4407      |                   |
     6.5  | 6202       | 5395      |                   |
     -----+------------+-----------+-------------------+

I think it's hopeless to convert to either over night, but it also seems 
clear that with-space was the preferred form until the use of the 
no-space form picked up dramatically following the addition, and then 
uptick in use, of _clang-format to qt5.git.

Absent a consensus on this, I'd suggest to use whatever you find to be 
predominant in the file/module you're editing.

> That said. I find discussing style-guides in general a waste of time, and will
> agree to anything that make us stop wasting time on this.

I tend to agree, but the choice is either to define it centrally, or you 
repeat these discussions on Gerrit over and over again.

Thanks,
Marc

-- 
Marc Mutz <marc.mutz at qt.io>
Principal Software Engineer

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