On 2019-06-06 15:49, Lars Knoll wrote:
On 6 Jun 2019, at 15:36, Mutz, Marc via Development
<development@qt-project.org> wrote:
On 2019-06-06 15:14, Konstantin Tokarev wrote:
[...]
There is a principle of single level of abstraction [1], and inline
implementation
of flat map can be viewed of violation of such principle. If flat map
implementations
were kept speparately, it would indeed make code easier to read and
maintain.
[1] http://principles-wiki.net/principles:single_level_of_abstraction
The code factors the setting and lookup into functions already. A
function is an abstraction. If you're concerned about a function that
calls find_if and then uses the result, how do you rate this one:
https://code.woboq.org/qt5/qtbase/src/widgets/kernel/qgesturemanager.cpp.html#_ZN15QGestureManager26filterEventThroughContextsERK9QMultiMapIP7QObjectN2Qt11GestureTypeEEP6QEvent
It's using _all_ the nice abstractions!
Puts some stuff into perspective, doesn't it?
Yes, the code in QGestureManager sucks. Basically because it abuses
our data structures in a really bad way.
But let’s not use the worst example you can find in Qt’s code base as
a comparison. Unmaintainable code in one place doesn’t justify doing
whatever you want in other places.
IMO, the code sucks because it conflates algorithms and data structures.
Wirth's book, however, is called Algorihms + Data Structures =
Programmes, not Data Structures = Programmes. Yet, that is exactly what
I feel is asked of me here: to hide the algorithms in a data structure.
But the end consequence of this is ... qgesturemanager.cpp.
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