using System;

namespace gaemstone.ECS;

[Tag]
public struct Relation {  }

/// <summary>
/// Marked entity represents a relationship type.
/// It may be used as the "relation" in a pair.
/// </summary>
/// <remarks>
/// The relationship may have component data associated with
/// it when added to an entity under these circumstances:
/// <list type="bullet">
///   <item>If marked as a <see cref="TagAttribute"/>, does not carry data.</item>
///   <item>If marked as a <see cref="ComponentAttribute"/>, carries the relation's data.</item>
///   <item>If marked with neither, will carry the target's data, if it's a component.</item>
/// </list>
/// </remarks>
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum)]
public class RelationAttribute : Attribute, ICreateEntityAttribute {  }