Sorting view

[ilumary]

I've tried sorting a view by entity id, however that does not work. What would be the correct way to sort entities without copying them?

auto view = registry.view<const ecs::entity&>().each()
std::sort(view.begin(), view.end(), [](std::tuple<const ecs::entity&> a, std::tuple<const ecs::entity&> b){
    return std::get<0>(a).id() < std::get<0>(b).id();
});

[Blyschak]

@ilumary Thanks for opening an issue. I believe this code should not compile. We can not sort entities directly in chunks as that would invalidate _entity_archetype_map. The sorting has to be supported by the registry in a similar way how it is done by entt: https://github.com/skypjack/entt/blob/e48817d518c0ada57665be07ba9961c19f71b502/test/benchmark/benchmark.cpp#L1092
Unfortunatelly I won't be able to add it right now but I would be glad to see a contribution.

[ilumary]

I have since been deeply involved in understanding your code and also came to the conclusion that sorting entities is not a practical feature considering your implementation. I must say, your ecs is remarkable. I have found a few bugs and did a few additions/improvements myself. Thought this repo was dead, but will open the corresponding issues/pull requests as soon as I do a bit of polishing.