[Development] Views

Ulf Hermann ulf.hermann at qt.io
Tue Jun 11 10:28:22 CEST 2019

Maybe we should move this into a more constructive direction:

I guess everybody can see that QMap and QHash are inefficient for 
containers with few items. Many of us also seem to agree that just 
repeating the sort/lookup on a vector all over the place is ugly and 
makes the code less readable.

So, not having read the discussion about the equivalent container in 
std, I'll make a naive suggestion here:

What about finding a QSortedVector that works for 90% of our internal 
cases and adding that as private API (for now). The remaining 10% will 
need custom solutions or keep using QHash/QMap, but replacing the 90% 
will give us most of the possible efficiency gains already.

I imagine that a vector which automatically sorts itself on the first 
lookup after any changes if it's larger than X items could be a drop-in 
replacement for most of the places where I misuse QHash or QMap. X could 
be a template parameter or found by some heuristic.


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