gaemstone/src/gaemstone/ECS/Rule.cs

using System;
using System.Collections;
using System.Collections.Generic;
using gaemstone.Utility;
using static flecs_hub.flecs;

namespace gaemstone.ECS;

public unsafe sealed class Rule
	: IEnumerable<Iterator>
	, IDisposable
{
	public Universe Universe { get; }
	public ecs_rule_t* Handle { get; }

	public Rule(Universe universe, FilterDesc desc)
	{
		using var alloc = TempAllocator.Use();
		var flecsDesc = desc.ToFlecs(alloc);
		Universe = universe;
		Handle   = ecs_rule_init(universe, &flecsDesc);
	}

	public void Dispose()
		=> ecs_rule_fini(this);

	public override string ToString()
		=> ecs_rule_str(Handle).FlecsToStringAndFree()!;

	public static implicit operator ecs_rule_t*(Rule q) => q.Handle;

	// IEnumerable implementation
	public Iterator Iter() => new(Universe, IteratorType.Rule, ecs_rule_iter(Universe, this));
	public IEnumerator<Iterator> GetEnumerator() => Iter().GetEnumerator();
	IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}