[Development] Some Qt3D feedback

[Marc Mutz]

On Thursday 11 June 2015 23:15:20 André Pönitz wrote:
> That's exactly the kind of situation I was referring to in my previous
> mail: This is intentionally introducing API inconsistency. It does not
> really matter to me whether "poor-man's prefix name spacing" is
> unfashionable or "we" consider it bad. It is simply inconsistent with
> more than 200 of existing exported QQuick*, QSG* and QQml* classes. 

For me, QQuick*, QSG*, QQml* are as much inconsistent with QtCore, QtGui and 
QtWidget (excepting QGraphics*) naming, where none of the types starts with 
poor man's prefix namespacing, as Qt3D::QParameter and QQml*.

Indeed, if you're working an a classical QtWidgets application, you might be 
very surprised about all those common prefixes in other modules, and annoyed 
by having useless code completion on class names beginning with QGraphics... 
:)

And as Qt grows and grows, the chance of name clashes increases 
(http://en.wikipedia.org/wiki/Birthday_problem), as witnessed by the 
introduction of namespaces for disambiguating names from QtQuick1 and 
QtDeclarative. QtMultimedia (which largely uses traditional names) has several 
common names, too. Namespaces, if the whole module is wrapped, and the 
namespace name is derived consistently from the module's soname, provide a 
reliable partition of the name space.

If a new library cannot change the established ways, including to experiment 
with it, then Qt will be forever locked in its 90s API, because, let's face 
it, come Qt 6, no-one will have the time to implement nor the incentive to 
break SC in such a broad way as to lift all of Qt to a new API standard, on 
top of all the work that will go into C++11/14-enabling the API, and the 
inevitable work on the containers. And the pain will grow and grow.

So, giving each module the leeway to modernize its API at its own pace seems 
to me the only workable solution. Of course, APIs should still be consistent, 
but whether a module uses namespaces or not doesn't really influence the 
consistency. Setters for text will still be called setText() and getters 
text(), QObject subclass' ctors will still end in QObject *parent = 
0^Wnullptr, etc.

Thanks,
Marc

-- 
Marc Mutz <marc.mutz at kdab.com> | Senior Software Engineer
KDAB (Deutschland) GmbH & Co.KG, a KDAB Group Company
Tel: +49-30-521325470
KDAB - The Qt Experts