[Development] Proposing to change https://wiki.qt.io/API_Design_Principles#Enums_in_classes to require scoped enums

[Marc Mutz]

Hi Tor Arne,

On 16.01.25 12:31, Tor Arne Vestbø wrote:
> 
>> On Jan 16, 2025, at 11:56, Marc Mutz via Development <development at qt-project.org> wrote:
>>
>> Like every API review, so also in 6.9, we have the discussions between
>> proponents of scoped vs. unscoped enums in class scope.
> 
> Indicating that it’s still a nuanced issue where each case might have different considerations and preferences.
> 
>> Can we, please, settle this by strengthening the wording of
>> https://wiki.qt.io/API_Design_Principles#Enums_in_classes to something
>> that requires scoped enums?
> 
> Yet your proposal is to ignore those nuances.

I don't. You just snipped that part of the email ;)

> -1
> 
>> is a very _un_-Qt-ish one. In Qt, we believe that brevity does not
>> automatically equal readability¹, and the more explicit
>>
>>> if (point.state() == TouchPoint::State::Pressed)
>>
>> is more (but certainly not less) readable than
>>
>>> if (point.state() == TouchPoint::Pressed)
> 
> Who is “we” here?

We as in the Qt project, having given us 
https://wiki.qt.io/API_Design_Principles, which reads

 > Readable code may sometimes take longer to write, but saves time
 > throughout the product's life cycle.

(in https://wiki.qt.io/API_Design_Principles#Lead_to_readable_code)

IOW: readability trumps brevity

> I for one would not agree with what you wrote above, so there’s your data point.
> 
> The latter is more readable to me due to lack of redundant information (“State::”)

I find the repetition comforting, reassuring me that the LHS and RHS 
match in semantics.

The question remains, though, how far we should go to sacrifice the objective 
technical benefits of using scoped enums for a (subjective) notion of 
readability?

Maybe have a second look at my suggestion to use scoped enums, but then 
break the scope with (the equivalent of) `using enum`? I think that 
might be a good compromise.

Thanks,
Marc

-- 
Marc Mutz <marc.mutz at qt.io> (he/his)
Principal Software Engineer

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