How to compare tow proxy objects?

[xuruilong100]

pro::proxy<EventComponent> event0 = ...;
pro::proxy<EventComponent> event1 = ...;
pro::proxy<EventComponent> event2 = ...;

std::vector<pro::proxy<EventComponent>> events;

auto it = std::remove(events.begin(), events.end(), event1);
events.erase(it, events.end());

The compiler tells me that my code is illegal, and event0 == event1 is illegal too.

So, how to compare two proxy objects?

[mingxwa]

@xuruilong100 By design, proxy is not equality comparable. If you want to remove an element from a std::vector<pro::proxy<>>, you need to implement a mechanism to find the index.

The implementation of == in Java or C# simply compares the address of two objects. If this is what you want, simply write add_convention<pro::operator_dispatch<"&">, const void*() const noexcept> when building facade EventComponent, then std::erase_if(events, [addr = &*event2](auto& p) { return &*p == addr; }) should work. (Note that std::remove won't actually shrink the vector).

If you want to compare the value of two objects, RTTI or other techniques should be used depending on your actual requirements.