Am 31.08.18 um 11:56 schrieb Tor Arne Vestbø:
I think Simon’s reasoning in the review that spurred this discussion summarises
it nicely:
On 31 Aug 2018, at 10:24, Simon Hausmann (Code Review)
<gerrit-nore...@qt-project.org> wrote:
Simon Hausmann has posted comments on this change.
Change subject: Convert QQEventPoint and QQPointerDevice enums to enum classes
......................................................................
Patch Set 7:
As excited I was initially with enum classes, I also start to dislike them when
looking at their use.
The counter example, QQuickPointerDevice::Mouse, is awesome.
QQuickPointerDevice::DeviceType::Mouse looks worse.
Always scoping leads to redundancy and never scoping leads to clashes. Enum
classes don't allow us to choose, they force us into the longer names. The
previous policy of prefixing _when needed_ gave us the flexibility to have lean
names when we could and longer names when required. For example
QuickItem::ItemHasContents.
So in terms of naming I find enum classes not truly winning. Perhaps they make us more
lazy in finding the best names, because just putting whatever we have in an enum class
"takes care of it".
The remaining argument in favor of enum classes is the type safety they add.
But at least inside Qt I've often seen it become an anti-pattern because we do
things in a more low-level fashion and need to cast to an int sometimes, for
example.
Given the names in this very API, I also disagree with commit message statement
that the existing scoping is insufficient. (See
QQuickPointerDevice::GrabState::GrabExclusive)
Based on the disagreement on how and when to use scoped enums, I think we
should change the style policy to:
- always recommend using scoped enums for global enums
- describe the pro’s and con’s of scoped enums inside classes
- ask the developer to consider each case individually
- and use good judgement in choosing one or the other
+1 on this.
Simon
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