KOpeningHours in kdereview

[Volker Krause]

Hi,

KOpeningHours is a library with C++ and QML API for parsing and evaluating OSM 
opening hours expressions. That might sound simple, and for basic cases like 
`Mo-Fr 09:00-17:00` it is, but it gets quite a bit more complex for more 
elaborate expressions that consider e.g. public holidays or seasonal changes.

https://invent.kde.org/libraries/kopeninghours

The most notable feature gap compared to the official specification is 
probably school holidays, we lack a collection of international data for that 
so far. That only occurs in about 2k out of the 1.8M opening hours expressions 
in the full OSM database, so that's not a massive problem in practice.

The API is prepared to handle the very similar OSM service time format ("point 
in time mode") as well, but evaluation for that hasn't been implemented yet.

The first users are KOSMIndoorMap and KDE Itinerary, for graying out elements 
on the map that aren't going to be available during a layover, and for showing 
a human-readable interpretation of the opening hours for a selected entity. 
You were at Akademy 2018 and got surprised by shops/restaurants suddenly being 
closed on Wednesday? That's exactly why you want this :)

PBI also has previously shown interest in supporting schema.org opening hours 
data, which KOpeningHours can consume as well. That was the original 
motivation to do this as a separate library, but meanwhile it's also being 
evaluated for use in OSM validation tooling: https://github.com/osm-fr/osmose-backend/issues/555. That has already resulted in a number of contributions 
increasing the tolerance for non-conforming expressions, which benefits all 
other use-cases as well.

Two command line demos and a QML example are included, if you want to try it 
I'd recommend to also get the latest KF5::Holidays to have all needed fixes 
and performance improvements.

My goal would be to have this join the release service for 21.04, so KDE 
Itinerary can properly depend on it.

Thanks,
Volker