gaemstone/src/gaemstone/ECS/Observer.cs

using System;
using static flecs_hub.flecs;

namespace gaemstone.ECS;

public enum ObserverEvent
{
	OnAdd              = ECS_HI_COMPONENT_ID + 33,
	OnRemove           = ECS_HI_COMPONENT_ID + 34,
	OnSet              = ECS_HI_COMPONENT_ID + 35,
	UnSet              = ECS_HI_COMPONENT_ID + 36,
	OnDelete           = ECS_HI_COMPONENT_ID + 37,
	OnCreateTable      = ECS_HI_COMPONENT_ID + 38,
	OnDeleteTable      = ECS_HI_COMPONENT_ID + 39,
	OnTableEmpty       = ECS_HI_COMPONENT_ID + 40,
	OnTableFill        = ECS_HI_COMPONENT_ID + 41,
	OnCreateTrigger    = ECS_HI_COMPONENT_ID + 42,
	OnDeleteTrigger    = ECS_HI_COMPONENT_ID + 43,
	OnDeleteObservable = ECS_HI_COMPONENT_ID + 44,
	OnComponentHooks   = ECS_HI_COMPONENT_ID + 45,
	OnDeleteTarget     = ECS_HI_COMPONENT_ID + 46,
}

[AttributeUsage(AttributeTargets.Method)]
public class ObserverAttribute : Attribute
{
	public ObserverEvent Event { get; }
	public string? Expression { get; }

	public ObserverAttribute(ObserverEvent @event)
		=> Event = @event;
}