Replace IActorInit with an abstract class.

A shared ValueActorInit<T> is introduced to reduce duplication
in the most common init cases, and an ActorInitActorReference
allow actors to be referenced by map.yaml name.

OpenRA.Game/Map/ActorInitializer.cs

@@ -10,7 +10,9 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using OpenRA.Primitives;
 using OpenRA.Traits;
 
@@ -19,11 +21,11 @@ namespace OpenRA
 	public interface IActorInitializer
 	{
 		World World { get; }
-		T GetOrDefault<T>(TraitInfo info) where T : IActorInit;
-		T Get<T>(TraitInfo info) where T : IActorInit;
-		U GetValue<T, U>(TraitInfo info) where T : IActorInit<U>;
-		U GetValue<T, U>(TraitInfo info, U fallback) where T : IActorInit<U>;
-		bool Contains<T>(TraitInfo info) where T : IActorInit;
+		T GetOrDefault<T>(TraitInfo info) where T : ActorInit;
+		T Get<T>(TraitInfo info) where T : ActorInit;
+		U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>;
+		U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>;
+		bool Contains<T>(TraitInfo info) where T : ActorInit;
 	}
 
 	public class ActorInitializer : IActorInitializer
@@ -39,12 +41,12 @@ namespace OpenRA
 			Dict = dict;
 		}
 
-		public T GetOrDefault<T>(TraitInfo info) where T : IActorInit
+		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
 			return Dict.GetOrDefault<T>();
 		}
 
-		public T Get<T>(TraitInfo info) where T : IActorInit
+		public T Get<T>(TraitInfo info) where T : ActorInit
 		{
 			var init = GetOrDefault<T>(info);
 			if (init == null)
@@ -53,59 +55,119 @@ namespace OpenRA
 			return init;
 		}
 
-		public U GetValue<T, U>(TraitInfo info) where T : IActorInit<U>
+		public U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>
 		{
 			return Get<T>(info).Value;
 		}
 
-		public U GetValue<T, U>(TraitInfo info, U fallback) where T : IActorInit<U>
+		public U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>
 		{
 			var init = GetOrDefault<T>(info);
 			return init != null ? init.Value : fallback;
 		}
 
-		public bool Contains<T>(TraitInfo info) where T : IActorInit { return GetOrDefault<T>(info) != null; }
+		public bool Contains<T>(TraitInfo info) where T : ActorInit { return GetOrDefault<T>(info) != null; }
 	}
 
-	public interface IActorInit { }
-
-	public interface IActorInit<T> : IActorInit
+	/*
+	 * Things to be aware of when writing ActorInits:
+	 *
+	 * - ActorReference and ActorGlobal can dynamically create objects without calling a constructor.
+	 *   The object will be allocated directly then the best matching Initialize() method will be called to set valid state.
+	 * - ActorReference will always attempt to call Initialize(MiniYaml). ActorGlobal will use whichever one it first
+	 *   finds with an argument type that matches the given LuaValue.
+	 * - Most ActorInits will want to inherit ValueActorInit<T> which hides the low-level plumbing.
+	 * - Inits that reference actors should use ActorInitActorReference which allows actors to be referenced by name in map.yaml
+	 */
+	public abstract class ActorInit
 	{
-		T Value { get; }
+		public abstract MiniYaml Save();
 	}
 
-	public class LocationInit : IActorInit<CPos>
+	public abstract class ValueActorInit<T> : ActorInit
 	{
-		[FieldFromYamlKey]
-		readonly CPos value = CPos.Zero;
+		protected readonly T value;
 
-		public LocationInit() { }
-		public LocationInit(CPos init) { value = init; }
-		public CPos Value { get { return value; } }
-	}
+		protected ValueActorInit(TraitInfo info, T value) { this.value = value; }
 
-	public class OwnerInit : IActorInit
-	{
-		[FieldFromYamlKey]
-		public readonly string InternalName = "Neutral";
+		protected ValueActorInit(T value) { this.value = value; }
 
-		Player player;
+		public virtual T Value { get { return value; } }
 
-		public OwnerInit() { }
-		public OwnerInit(string playerName) { InternalName = playerName; }
-
-		public OwnerInit(Player player)
+		public virtual void Initialize(MiniYaml yaml)
 		{
-			this.player = player;
-			InternalName = player.InternalName;
+			var valueType = typeof(T).IsEnum ? Enum.GetUnderlyingType(typeof(T)) : typeof(T);
+			Initialize((T)FieldLoader.GetValue("value", valueType, yaml.Value));
+		}
+
+		public virtual void Initialize(T value)
+		{
+			var field = GetType().GetField("value", BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, value);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(FieldSaver.FormatValue(value));
+		}
+	}
+
+	public class LocationInit : ValueActorInit<CPos>
+	{
+		public LocationInit(TraitInfo info, CPos value)
+			: base(info, value) { }
+
+		public LocationInit(CPos value)
+			: base(value) { }
+	}
+
+	public class OwnerInit : ActorInit
+	{
+		public readonly string InternalName;
+		protected readonly Player value;
+
+		public OwnerInit(Player value)
+		{
+			this.value = value;
+			InternalName = value.InternalName;
+		}
+
+		public OwnerInit(string value)
+		{
+			InternalName = value;
 		}
 
 		public Player Value(World world)
 		{
-			if (player != null)
-				return player;
+			return value ?? world.Players.First(x => x.InternalName == InternalName);
+		}
 
-			return world.Players.First(x => x.InternalName == InternalName);
+		public void Initialize(MiniYaml yaml)
+		{
+			var field = GetType().GetField("InternalName", BindingFlags.Public | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, yaml.Value);
+		}
+
+		public void Initialize(Player player)
+		{
+			var field = GetType().GetField("value", BindingFlags.NonPublic | BindingFlags.Instance);
+			if (field != null)
+				field.SetValue(this, player);
+		}
+
+		public override MiniYaml Save()
+		{
+			return new MiniYaml(InternalName);
+		}
+	}
+
+	public abstract class RuntimeFlagInit : ActorInit, ISuppressInitExport
+	{
+		public override MiniYaml Save()
+		{
+			throw new NotImplementedException("RuntimeFlagInit cannot be saved");
 		}
 	}
 }

OpenRA.Game/Map/ActorReference.cs

@@ -12,6 +12,8 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.IO;
+using System.Runtime.Serialization;
 using OpenRA.Primitives;
 
 namespace OpenRA
@@ -43,26 +45,36 @@ namespace OpenRA
 			});
 		}
 
-		static IActorInit LoadInit(string traitName, MiniYaml my)
+		static ActorInit LoadInit(string initName, MiniYaml initYaml)
 		{
-			var info = Game.CreateObject<IActorInit>(traitName + "Init");
-			FieldLoader.Load(info, my);
-			return info;
+			var type = Game.ModData.ObjectCreator.FindType(initName + "Init");
+			if (type == null)
+				throw new InvalidDataException("Unknown initializer type '{0}Init'".F(initName));
+
+			var init = (ActorInit)FormatterServices.GetUninitializedObject(type);
+			var loader = type.GetMethod("Initialize", new[] { typeof(MiniYaml) });
+			if (loader == null)
+				throw new InvalidDataException("{0}Init does not define a yaml-assignable type.".F(initName));
+
+			loader.Invoke(init, new[] { initYaml });
+			return init;
 		}
 
-		public MiniYaml Save(Func<object, bool> initFilter = null)
+		public MiniYaml Save(Func<ActorInit, bool> initFilter = null)
 		{
 			var ret = new MiniYaml(Type);
-			foreach (var init in InitDict)
+			foreach (var o in InitDict)
 			{
-				if (init is ISuppressInitExport)
+				var init = o as ActorInit;
+				if (init == null || o is ISuppressInitExport)
 					continue;
 
 				if (initFilter != null && !initFilter(init))
 					continue;
 
-				var initName = init.GetType().Name;
-				ret.Nodes.Add(new MiniYamlNode(initName.Substring(0, initName.Length - 4), FieldSaver.Save(init)));
+				var initTypeName = init.GetType().Name;
+				var initName = initTypeName.Substring(0, initTypeName.Length - 4);
+				ret.Nodes.Add(new MiniYamlNode(initName, init.Save()));
 			}
 
 			return ret;

OpenRA.Mods.Cnc/Traits/Chronoshiftable.cs

@@ -11,6 +11,7 @@
 
 using System;
 using OpenRA.Mods.Cnc.Activities;
+using OpenRA.Mods.Common;
 using OpenRA.Mods.Common.Activities;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Primitives;
@@ -66,7 +67,7 @@ namespace OpenRA.Mods.Cnc.Traits
 			// Defer to the end of tick as the lazy value may reference an actor that hasn't been created yet
 			var chronosphereInit = init.GetOrDefault<ChronoshiftChronosphereInit>(info);
 			if (chronosphereInit != null)
-				init.World.AddFrameEndTask(w => chronosphere = chronosphereInit.Value(init.World).Value);
+				init.World.AddFrameEndTask(w => chronosphere = chronosphereInit.Value.Actor(init.World).Value);
 		}
 
 		void ITick.Tick(Actor self)
@@ -176,40 +177,27 @@ namespace OpenRA.Mods.Cnc.Traits
 		void ITransformActorInitModifier.ModifyTransformActorInit(Actor self, TypeDictionary init) { ModifyActorInit(init); }
 	}
 
-	public class ChronoshiftReturnInit : IActorInit<int>
+	public class ChronoshiftReturnInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 0;
-
-		public ChronoshiftReturnInit() { }
-		public ChronoshiftReturnInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public ChronoshiftReturnInit(int value)
+			: base(value) { }
 	}
 
-	public class ChronoshiftDurationInit : IActorInit<int>
+	public class ChronoshiftDurationInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 0;
-
-		public ChronoshiftDurationInit() { }
-		public ChronoshiftDurationInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public ChronoshiftDurationInit(int value)
+			: base(value) { }
 	}
 
-	public class ChronoshiftOriginInit : IActorInit<CPos>
+	public class ChronoshiftOriginInit : ValueActorInit<CPos>
 	{
-		[FieldFromYamlKey]
-		readonly CPos value;
-
-		public ChronoshiftOriginInit(CPos init) { value = init; }
-		public CPos Value { get { return value; } }
+		public ChronoshiftOriginInit(CPos value)
+			: base(value) { }
 	}
 
-	public class ChronoshiftChronosphereInit : IActorInit
+	public class ChronoshiftChronosphereInit : ValueActorInit<ActorInitActorReference>
 	{
-		readonly Actor value;
-		public ChronoshiftChronosphereInit(Actor init) { value = init; }
-
-		public Lazy<Actor> Value(World world) { return new Lazy<Actor>(() => value); }
+		public ChronoshiftChronosphereInit(Actor value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Cnc/Traits/ConyardChronoReturn.cs

@@ -103,7 +103,7 @@ namespace OpenRA.Mods.Cnc.Traits
 			// Defer to the end of tick as the lazy value may reference an actor that hasn't been created yet
 			var chronosphereInit = init.GetOrDefault<ChronoshiftChronosphereInit>(info);
 			if (chronosphereInit != null)
-				init.World.AddFrameEndTask(w => chronosphere = chronosphereInit.Value(init.World).Value);
+				init.World.AddFrameEndTask(w => chronosphere = chronosphereInit.Value.Actor(init.World).Value);
 		}
 
 		IEnumerable<VariableObserver> IObservesVariables.GetVariableObservers()

OpenRA.Mods.Cnc/Traits/Render/WithBuildingBib.cs

@@ -133,8 +133,5 @@ namespace OpenRA.Mods.Cnc.Traits
 		}
 	}
 
-	class HideBibPreviewInit : IActorInit, ISuppressInitExport
-	{
-		public HideBibPreviewInit() { }
-	}
+	class HideBibPreviewInit : RuntimeFlagInit { }
 }

OpenRA.Mods.Cnc/Traits/Render/WithVoxelWalkerBody.cs

@@ -95,13 +95,9 @@ namespace OpenRA.Mods.Cnc.Traits.Render
 		}
 	}
 
-	public class BodyAnimationFrameInit : IActorInit<uint>
+	public class BodyAnimationFrameInit : ValueActorInit<uint>
 	{
-		[FieldFromYamlKey]
-		readonly uint value = 0;
-
-		public BodyAnimationFrameInit() { }
-		public BodyAnimationFrameInit(uint init) { value = init; }
-		public uint Value { get { return value; } }
+		public BodyAnimationFrameInit(uint value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/ActorInitializer.cs

@@ -10,77 +10,128 @@
 #endregion
 
 using System;
+using System.ComponentModel;
+using OpenRA.Mods.Common.Traits;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common
 {
-	public class FacingInit : IActorInit<int>
+	public class FacingInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 128;
-
-		public FacingInit() { }
-		public FacingInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public FacingInit(int value)
+			: base(value) { }
 	}
 
-	public class CreationActivityDelayInit : IActorInit<int>
+	public class CreationActivityDelayInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 0;
-
-		public CreationActivityDelayInit() { }
-		public CreationActivityDelayInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public CreationActivityDelayInit(int value)
+			: base(value) { }
 	}
 
-	public class DynamicFacingInit : IActorInit<Func<int>>
+	public class DynamicFacingInit : ValueActorInit<Func<int>>
 	{
-		readonly Func<int> func;
-
-		public DynamicFacingInit(Func<int> func) { this.func = func; }
-		public Func<int> Value { get { return func; } }
+		public DynamicFacingInit(Func<int> value)
+			: base(value) { }
 	}
 
-	public class SubCellInit : IActorInit<SubCell>
+	public class SubCellInit : ValueActorInit<SubCell>
 	{
-		[FieldFromYamlKey]
-		readonly byte value = (byte)SubCell.FullCell;
-
-		public SubCellInit() { }
-		public SubCellInit(byte init) { value = init; }
-		public SubCellInit(SubCell init) { value = (byte)init; }
-		public SubCell Value { get { return (SubCell)value; } }
+		public SubCellInit(SubCell value)
+			: base(value) { }
 	}
 
-	public class CenterPositionInit : IActorInit<WPos>
+	public class CenterPositionInit : ValueActorInit<WPos>
 	{
-		[FieldFromYamlKey]
-		readonly WPos value = WPos.Zero;
-
-		public CenterPositionInit() { }
-		public CenterPositionInit(WPos init) { value = init; }
-		public WPos Value { get { return value; } }
+		public CenterPositionInit(WPos value)
+			: base(value) { }
 	}
 
 	// Allows maps / transformations to specify the faction variant of an actor.
-	public class FactionInit : IActorInit<string>
+	public class FactionInit : ValueActorInit<string>
 	{
-		[FieldFromYamlKey]
-		public readonly string Faction;
-
-		public FactionInit() { }
-		public FactionInit(string faction) { Faction = faction; }
-		public string Value { get { return Faction; } }
+		public FactionInit(string value)
+			: base(value) { }
 	}
 
-	public class EffectiveOwnerInit : IActorInit<Player>
+	public class EffectiveOwnerInit : ValueActorInit<Player>
 	{
-		[FieldFromYamlKey]
-		readonly Player value = null;
+		public EffectiveOwnerInit(Player value)
+			: base(value) { }
+	}
 
-		public EffectiveOwnerInit() { }
-		public EffectiveOwnerInit(Player owner) { value = owner; }
-		public Player Value { get { return value; } }
+	internal class ActorInitLoader : TypeConverter
+	{
+		public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+		{
+			return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
+		}
+
+		public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
+		{
+			return new ActorInitActorReference(value as string);
+		}
+
+		public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
+		{
+			return destinationType == typeof(string) || base.CanConvertTo(context, destinationType);
+		}
+
+		public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
+		{
+			if (destinationType == typeof(string))
+			{
+				var reference = value as ActorInitActorReference;
+				if (reference != null)
+					return reference.InternalName;
+			}
+
+			return base.ConvertTo(context, culture, value, destinationType);
+		}
+	}
+
+	[TypeConverter(typeof(ActorInitLoader))]
+	public class ActorInitActorReference
+	{
+		public readonly string InternalName;
+		readonly Actor actor;
+
+		public ActorInitActorReference(Actor actor)
+		{
+			this.actor = actor;
+		}
+
+		public ActorInitActorReference(string internalName)
+		{
+			InternalName = internalName;
+		}
+
+		Actor InnerValue(World world)
+		{
+			if (actor != null)
+				return actor;
+
+			var sma = world.WorldActor.Trait<SpawnMapActors>();
+			return sma.Actors[InternalName];
+		}
+
+		/// <summary>
+		/// The lazy value may reference other actors that have not been created
+		/// yet, so must not be resolved from the actor constructor or Created method.
+		/// Use a FrameEndTask or wait until it is actually needed.
+		/// </summary>
+		public Lazy<Actor> Actor(World world)
+		{
+			return new Lazy<Actor>(() => InnerValue(world));
+		}
+
+		public static implicit operator ActorInitActorReference(Actor a)
+		{
+			return new ActorInitActorReference(a);
+		}
+
+		public static implicit operator ActorInitActorReference(string mapName)
+		{
+			return new ActorInitActorReference(mapName);
+		}
 	}
 }

OpenRA.Mods.Common/Graphics/ActorPreview.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Primitives;
@@ -41,12 +42,12 @@ namespace OpenRA.Mods.Common.Graphics
 			this.dict = dict;
 		}
 
-		public T GetOrDefault<T>(TraitInfo info) where T : IActorInit
+		public T GetOrDefault<T>(TraitInfo info) where T : ActorInit
 		{
 			return dict.GetOrDefault<T>();
 		}
 
-		public T Get<T>(TraitInfo info) where T : IActorInit
+		public T Get<T>(TraitInfo info) where T : ActorInit
 		{
 			var init = GetOrDefault<T>(info);
 			if (init == null)
@@ -55,18 +56,18 @@ namespace OpenRA.Mods.Common.Graphics
 			return init;
 		}
 
-		public U GetValue<T, U>(TraitInfo info) where T : IActorInit<U>
+		public U GetValue<T, U>(TraitInfo info) where T : ValueActorInit<U>
 		{
 			return Get<T>(info).Value;
 		}
 
-		public U GetValue<T, U>(TraitInfo info, U fallback) where T : IActorInit<U>
+		public U GetValue<T, U>(TraitInfo info, U fallback) where T : ValueActorInit<U>
 		{
 			var init = GetOrDefault<T>(info);
 			return init != null ? init.Value : fallback;
 		}
 
-		public bool Contains<T>(TraitInfo info) where T : IActorInit { return GetOrDefault<T>(info) != null; }
+		public bool Contains<T>(TraitInfo info) where T : ActorInit { return GetOrDefault<T>(info) != null; }
 
 		public Func<WRot> GetOrientation()
 		{

OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs

@@ -10,7 +10,10 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
+using System.Runtime.Serialization;
 using Eluant;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Primitives;
@@ -24,6 +27,37 @@ namespace OpenRA.Mods.Common.Scripting
 		public ActorGlobal(ScriptContext context)
 			: base(context) { }
 
+		ActorInit CreateInit(string initName, LuaValue value)
+		{
+			// Find the requested type
+			var initType = Game.ModData.ObjectCreator.FindType(initName + "Init");
+			if (initType == null)
+				throw new LuaException("Unknown initializer type '{0}'".F(initName));
+
+			// Construct the ActorInit.
+			var init = (ActorInit)FormatterServices.GetUninitializedObject(initType);
+			var initializers = initType.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
+				.Where(m => m.Name == "Initialize" && m.GetParameters().Length == 1);
+
+			foreach (var initializer in initializers)
+			{
+				var parameterType = initializer.GetParameters().First().ParameterType;
+				var valueType = parameterType.IsEnum ? Enum.GetUnderlyingType(parameterType) : parameterType;
+
+				// Try and coerce the table value to the required type
+				object clrValue;
+				if (!value.TryGetClrValue(valueType, out clrValue))
+					continue;
+
+				initializer.Invoke(init, new[] { clrValue });
+
+				return init;
+			}
+
+			var types = initializers.Select(y => y.GetParameters()[0].ParameterType.Name).JoinWith(", ");
+			throw new LuaException("Invalid data type for '{0}' (expected one of {1})".F(initName, types));
+		}
+
 		[Desc("Create a new actor. initTable specifies a list of key-value pairs that defines the initial parameters for the actor's traits.")]
 		public Actor Create(string type, bool addToWorld, LuaTable initTable)
 		{
@@ -34,35 +68,7 @@ namespace OpenRA.Mods.Common.Scripting
 			{
 				using (kv.Key)
 				using (kv.Value)
-				{
-					// Find the requested type
-					var typeName = kv.Key.ToString();
-					var initType = Game.ModData.ObjectCreator.FindType(typeName + "Init");
-					if (initType == null)
-						throw new LuaException("Unknown initializer type '{0}'".F(typeName));
-
-					// HACK: Handle OwnerInit as a special case until ActorInit creation can be rewritten
-					Type innerType, valueType;
-					if (initType != typeof(OwnerInit))
-					{
-						// Cast it up to an IActorInit<T>
-						var genericType = initType.GetInterfaces()
-							.First(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IActorInit<>));
-						innerType = genericType.GetGenericArguments().First();
-						valueType = innerType.IsEnum ? Enum.GetUnderlyingType(innerType) : innerType;
-					}
-					else
-						innerType = valueType = typeof(Player);
-
-					// Try and coerce the table value to the required type
-					object value;
-					if (!kv.Value.TryGetClrValue(valueType, out value))
-						throw new LuaException("Invalid data type for '{0}' (expected '{1}')".F(typeName, valueType.Name));
-
-					// Construct the ActorInit. Phew!
-					var test = initType.GetConstructor(new[] { innerType }).Invoke(new[] { value });
-					initDict.Add(test);
-				}
+					initDict.Add(CreateInit(kv.Key.ToString(), kv.Value));
 			}
 
 			var owner = initDict.GetOrDefault<OwnerInit>();

OpenRA.Mods.Common/Traits/AutoTarget.cs

@@ -123,7 +123,7 @@ namespace OpenRA.Mods.Common.Traits
 					var stance = init != null ? init.Value : InitialStance;
 					return stances[(int)stance];
 				},
-				(actor, value) => actor.ReplaceInit(new StanceInit((UnitStance)stances.IndexOf(value))));
+				(actor, value) => actor.ReplaceInit(new StanceInit(this, (UnitStance)stances.IndexOf(value))));
 		}
 	}
 
@@ -445,13 +445,9 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class StanceInit : IActorInit<UnitStance>
+	public class StanceInit : ValueActorInit<UnitStance>
 	{
-		[FieldFromYamlKey]
-		readonly UnitStance value = UnitStance.AttackAnything;
-
-		public StanceInit() { }
-		public StanceInit(UnitStance init) { value = init; }
-		public UnitStance Value { get { return value; } }
+		public StanceInit(TraitInfo info, UnitStance value)
+			: base(info, value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Buildings/FreeActor.cs

@@ -50,7 +50,7 @@ namespace OpenRA.Mods.Common.Traits
 				},
 				(actor, value) =>
 				{
-					actor.ReplaceInit(new FreeActorInit(value));
+					actor.ReplaceInit(new FreeActorInit(this, value));
 				});
 		}
 
@@ -87,20 +87,15 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class FreeActorInit : IActorInit<bool>
+	public class FreeActorInit : ValueActorInit<bool>
 	{
-		[FieldFromYamlKey]
-		public readonly bool ActorValue = true;
-		public FreeActorInit() { }
-		public FreeActorInit(bool init) { ActorValue = init; }
-		public bool Value { get { return ActorValue; } }
+		public FreeActorInit(TraitInfo info, bool value)
+			: base(info, value) { }
 	}
 
-	public class ParentActorInit : IActorInit
+	public class ParentActorInit : ValueActorInit<ActorInitActorReference>
 	{
-		readonly Actor value;
-		public ParentActorInit(Actor init) { value = init; }
-
-		public Lazy<Actor> Value(World world) { return new Lazy<Actor>(() => value); }
+		public ParentActorInit(Actor value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Buildings/LegacyBridgeHut.cs

@@ -33,10 +33,10 @@ namespace OpenRA.Mods.Common.Traits
 
 		public LegacyBridgeHut(ActorInitializer init, LegacyBridgeHutInfo info)
 		{
-			var bridge = init.GetOrDefault<ParentActorInit>(info);
+			var bridge = init.Get<ParentActorInit>(info).Value;
 			init.World.AddFrameEndTask(_ =>
 			{
-				Bridge = bridge.Value(init.World).Value.Trait<Bridge>();
+				Bridge = bridge.Actor(init.World).Value.Trait<Bridge>();
 				Bridge.AddHut(this);
 				FirstBridge = Bridge.Enumerate(0, true).Last();
 			});

OpenRA.Mods.Common/Traits/Buildings/LineBuild.cs

@@ -16,33 +16,29 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	public enum LineBuildDirection { Unset, X, Y }
-	public class LineBuildDirectionInit : IActorInit<LineBuildDirection>
+	public class LineBuildDirectionInit : ValueActorInit<LineBuildDirection>
 	{
-		[FieldFromYamlKey]
-		readonly LineBuildDirection value = LineBuildDirection.Unset;
-
-		public LineBuildDirectionInit() { }
-		public LineBuildDirectionInit(LineBuildDirection init) { value = init; }
-		public LineBuildDirection Value { get { return value; } }
+		public LineBuildDirectionInit(LineBuildDirection value)
+			: base(value) { }
 	}
 
-	public class LineBuildParentInit : IActorInit<string[]>
+	public class LineBuildParentInit : ValueActorInit<string[]>
 	{
-		[FieldFromYamlKey]
-		public readonly string[] ParentNames = new string[0];
-
 		readonly Actor[] parents = null;
 
-		public LineBuildParentInit() { }
-		public LineBuildParentInit(Actor[] init) { parents = init; }
-		public string[] Value { get { return ParentNames; } }
+		public LineBuildParentInit(Actor[] value)
+			: base(new string[0])
+		{
+			parents = value;
+		}
+
 		public Actor[] ActorValue(World world)
 		{
 			if (parents != null)
 				return parents;
 
 			var sma = world.WorldActor.Trait<SpawnMapActors>();
-			return ParentNames.Select(n => sma.Actors[n]).ToArray();
+			return value.Select(n => sma.Actors[n]).ToArray();
 		}
 	}
 

OpenRA.Mods.Common/Traits/Cargo.cs

@@ -479,25 +479,19 @@ namespace OpenRA.Mods.Common.Traits
 
 		void ITransformActorInitModifier.ModifyTransformActorInit(Actor self, TypeDictionary init)
 		{
-			init.Add(new RuntimeCargoInit(Passengers.ToArray()));
+			init.Add(new RuntimeCargoInit(Info, Passengers.ToArray()));
 		}
 	}
 
-	public class RuntimeCargoInit : IActorInit<Actor[]>, ISuppressInitExport
+	public class RuntimeCargoInit : ValueActorInit<Actor[]>, ISuppressInitExport
 	{
-		[FieldFromYamlKey]
-		readonly Actor[] value = { };
-		public RuntimeCargoInit() { }
-		public RuntimeCargoInit(Actor[] init) { value = init; }
-		public Actor[] Value { get { return value; } }
+		public RuntimeCargoInit(TraitInfo info, Actor[] value)
+			: base(info, value) { }
 	}
 
-	public class CargoInit : IActorInit<string[]>
+	public class CargoInit : ValueActorInit<string[]>
 	{
-		[FieldFromYamlKey]
-		readonly string[] value = { };
-		public CargoInit() { }
-		public CargoInit(string[] init) { value = init; }
-		public string[] Value { get { return value; } }
+		public CargoInit(TraitInfo info, string[] value)
+			: base(info, value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Conditions/GrantConditionOnDeploy.cs

@@ -80,7 +80,7 @@ namespace OpenRA.Mods.Common.Traits
 				},
 				(actor, value) =>
 				{
-					actor.ReplaceInit(new DeployStateInit(value ? DeployState.Deployed : DeployState.Undeployed));
+					actor.ReplaceInit(new DeployStateInit(this, value ? DeployState.Deployed : DeployState.Undeployed));
 				});
 		}
 
@@ -337,12 +337,12 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class DeployStateInit : IActorInit<DeployState>
+	public class DeployStateInit : ValueActorInit<DeployState>
 	{
-		[FieldFromYamlKey]
-		readonly DeployState value = DeployState.Deployed;
-		public DeployStateInit() { }
-		public DeployStateInit(DeployState init) { value = init; }
-		public DeployState Value { get { return value; } }
+		public DeployStateInit(TraitInfo info, DeployState value)
+			: base(info, value) { }
+
+		public DeployStateInit(DeployState value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/GainsExperience.cs

@@ -141,17 +141,13 @@ namespace OpenRA.Mods.Common.Traits
 
 		void ITransformActorInitModifier.ModifyTransformActorInit(Actor self, TypeDictionary init)
 		{
-			init.Add(new ExperienceInit(experience));
+			init.Add(new ExperienceInit(info, experience));
 		}
 	}
 
-	class ExperienceInit : IActorInit<int>
+	class ExperienceInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value;
-
-		public ExperienceInit() { }
-		public ExperienceInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public ExperienceInit(TraitInfo info, int value)
+			: base(info, value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Health.cs

@@ -233,23 +233,17 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class HealthInit : IActorInit<int>
+	public class HealthInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 100;
-
 		readonly bool allowZero;
-		public HealthInit() { }
-		public HealthInit(int init)
-			: this(init, false) { }
 
-		public HealthInit(int init, bool allowZero)
-		{
-			this.allowZero = allowZero;
-			value = init;
-		}
+		public HealthInit(TraitInfo info, int value, bool allowZero = false)
+			: base(info, value) { this.allowZero = allowZero; }
 
-		public int Value
+		public HealthInit(int value, bool allowZero = false)
+			: base(value) { this.allowZero = allowZero; }
+
+		public override int Value
 		{
 			get
 			{

OpenRA.Mods.Common/Traits/Husk.cs

@@ -171,13 +171,9 @@ namespace OpenRA.Mods.Common.Traits
 		Player IEffectiveOwner.Owner { get { return effectiveOwner; } }
 	}
 
-	public class HuskSpeedInit : IActorInit<int>
+	public class HuskSpeedInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 0;
-
-		public HuskSpeedInit() { }
-		public HuskSpeedInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public HuskSpeedInit(int value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -146,7 +146,7 @@ namespace OpenRA.Mods.Common.Traits
 					if (turretInit != null)
 					{
 						var newTurretFacing = (turretInit.Value + newFacing - oldFacing + 255) % 255;
-						actor.ReplaceInit(new TurretFacingInit(newTurretFacing));
+						actor.ReplaceInit(new TurretFacingInit(this, newTurretFacing));
 					}
 
 					if (turretsInit != null)

OpenRA.Mods.Common/Traits/Modifiers/FrozenUnderFog.cs

@@ -195,5 +195,5 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class HiddenUnderFogInit : IActorInit { }
+	public class HiddenUnderFogInit : RuntimeFlagInit { }
 }

OpenRA.Mods.Common/Traits/Player/PlaceBuilding.cs

@@ -16,7 +16,7 @@ using OpenRA.Traits;
 namespace OpenRA.Mods.Common.Traits
 {
 	// Allows third party mods to detect whether an actor was created by PlaceBuilding.
-	public class PlaceBuildingInit : IActorInit { }
+	public class PlaceBuildingInit : RuntimeFlagInit { }
 
 	[Desc("Allows the player to execute build orders.", " Attach this to the player actor.")]
 	public class PlaceBuildingInfo : TraitInfo

OpenRA.Mods.Common/Traits/Pluggable.cs

@@ -120,12 +120,9 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class PlugsInit : IActorInit<Dictionary<CVec, string>>
+	public class PlugsInit : ValueActorInit<Dictionary<CVec, string>>
 	{
-		[DictionaryFromYamlKey]
-		readonly Dictionary<CVec, string> value = new Dictionary<CVec, string>();
-		public PlugsInit() { }
-		public PlugsInit(Dictionary<CVec, string> init) { value = init; }
-		public Dictionary<CVec, string> Value { get { return value; } }
+		public PlugsInit(Dictionary<CVec, string> value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/ProductionFromMapEdge.cs

@@ -110,13 +110,9 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class ProductionSpawnLocationInit : IActorInit<CPos>
+	public class ProductionSpawnLocationInit : ValueActorInit<CPos>
 	{
-		[FieldFromYamlKey]
-		readonly CPos value = CPos.Zero;
-
-		public ProductionSpawnLocationInit() { }
-		public ProductionSpawnLocationInit(CPos init) { value = init; }
-		public CPos Value { get { return value; } }
+		public ProductionSpawnLocationInit(TraitInfo info, CPos value)
+			: base(info, value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Render/WithWallSpriteBody.cs

@@ -168,13 +168,9 @@ namespace OpenRA.Mods.Common.Traits.Render
 		}
 	}
 
-	public class RuntimeNeighbourInit : IActorInit<Dictionary<CPos, string[]>>, ISuppressInitExport
+	public class RuntimeNeighbourInit : ValueActorInit<Dictionary<CPos, string[]>>, ISuppressInitExport
 	{
-		[FieldFromYamlKey]
-		readonly Dictionary<CPos, string[]> value = null;
-
-		public RuntimeNeighbourInit() { }
-		public RuntimeNeighbourInit(Dictionary<CPos, string[]> init) { value = init; }
-		public Dictionary<CPos, string[]> Value { get { return value; } }
+		public RuntimeNeighbourInit(Dictionary<CPos, string[]> value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/ScriptTags.cs

@@ -49,13 +49,9 @@ namespace OpenRA.Mods.Common.Traits
 	}
 
 	/// <summary>Allows mappers to 'tag' actors with arbitrary strings that may have meaning in their scripts.</summary>
-	public class ScriptTagsInit : IActorInit<string[]>
+	public class ScriptTagsInit : ValueActorInit<string[]>
 	{
-		[FieldFromYamlKey]
-		readonly string[] value = new string[0];
-
-		public ScriptTagsInit() { }
-		public ScriptTagsInit(string[] init) { value = init; }
-		public string[] Value { get { return value; } }
+		public ScriptTagsInit(string[] value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/Traits/Turreted.cs

@@ -41,7 +41,7 @@ namespace OpenRA.Mods.Common.Traits
 			// HACK: The ActorInit system does not support multiple instances of the same type
 			// Make sure that we only return one TurretFacingInit, even for actors with multiple turrets
 			if (ai.TraitInfos<TurretedInfo>().FirstOrDefault() == this)
-				yield return new TurretFacingInit(PreviewFacing);
+				yield return new TurretFacingInit(this, PreviewFacing);
 		}
 
 		IEnumerable<EditorActorOption> IEditorActorOptions.ActorOptions(ActorInfo ai, World world)
@@ -66,6 +66,8 @@ namespace OpenRA.Mods.Common.Traits
 				(actor, value) =>
 				{
 					actor.RemoveInit<TurretFacingsInit>();
+
+					// Force a single global turret facing for multi-turret actors by not passing this TraitInfo instance
 					actor.ReplaceInit(new TurretFacingInit((int)value));
 				});
 		}
@@ -230,7 +232,7 @@ namespace OpenRA.Mods.Common.Traits
 			var facings = init.GetOrDefault<TurretFacingsInit>();
 			if (facings == null)
 			{
-				facings = new TurretFacingsInit();
+				facings = new TurretFacingsInit(new Dictionary<string, int>());
 				init.Add(facings);
 			}
 
@@ -243,7 +245,7 @@ namespace OpenRA.Mods.Common.Traits
 			var facings = inits.GetOrDefault<DynamicTurretFacingsInit>();
 			if (facings == null)
 			{
-				facings = new DynamicTurretFacingsInit();
+				facings = new DynamicTurretFacingsInit(Info, new Dictionary<string, Func<int>>());
 				inits.Add(facings);
 			}
 
@@ -267,31 +269,24 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class TurretFacingInit : IActorInit<int>
+	public class TurretFacingInit : ValueActorInit<int>
 	{
-		[FieldFromYamlKey]
-		readonly int value = 128;
+		public TurretFacingInit(TraitInfo info, int value)
+			: base(info, value) { }
 
-		public TurretFacingInit() { }
-		public TurretFacingInit(int init) { value = init; }
-		public int Value { get { return value; } }
+		public TurretFacingInit(int value)
+			: base(value) { }
 	}
 
-	public class TurretFacingsInit : IActorInit<Dictionary<string, int>>
+	public class TurretFacingsInit : ValueActorInit<Dictionary<string, int>>
 	{
-		[DictionaryFromYamlKey]
-		readonly Dictionary<string, int> value = new Dictionary<string, int>();
-
-		public TurretFacingsInit() { }
-		public TurretFacingsInit(Dictionary<string, int> init) { value = init; }
-		public Dictionary<string, int> Value { get { return value; } }
+		public TurretFacingsInit(Dictionary<string, int> value)
+			: base(value) { }
 	}
 
-	public class DynamicTurretFacingsInit : IActorInit<Dictionary<string, Func<int>>>
+	public class DynamicTurretFacingsInit : ValueActorInit<Dictionary<string, Func<int>>>
 	{
-		readonly Dictionary<string, Func<int>> value = new Dictionary<string, Func<int>>();
-		public DynamicTurretFacingsInit() { }
-		public DynamicTurretFacingsInit(Dictionary<string, Func<int>> init) { value = init; }
-		public Dictionary<string, Func<int>> Value { get { return value; } }
+		public DynamicTurretFacingsInit(TraitInfo info, Dictionary<string, Func<int>> value)
+			: base(info, value) { }
 	}
 }

OpenRA.Mods.Common/Traits/World/SpawnMapActors.cs

@@ -62,12 +62,10 @@ namespace OpenRA.Mods.Common.Traits
 		}
 	}
 
-	public class SkipMakeAnimsInit : IActorInit, ISuppressInitExport { }
-	public class SpawnedByMapInit : IActorInit<string>, ISuppressInitExport
+	public class SkipMakeAnimsInit : RuntimeFlagInit { }
+	public class SpawnedByMapInit : ValueActorInit<string>, ISuppressInitExport
 	{
-		public readonly string Name;
-		public SpawnedByMapInit(string name) { Name = name; }
-
-		public string Value { get { return Name; } }
+		public SpawnedByMapInit(string value)
+			: base(value) { }
 	}
 }

OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs

@@ -19,6 +19,7 @@ using OpenRA.Graphics;
 using OpenRA.Mods.Common.FileFormats;
 using OpenRA.Mods.Common.Traits;
 using OpenRA.Primitives;
+using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.UtilityCommands
 {
@@ -416,7 +417,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 						initDict.Add(new FacingInit(255 - facing));
 
 					if (section == "INFANTRY")
-						actor.Add(new SubCellInit(Exts.ParseByte(parts[4])));
+						actor.Add(new SubCellInit((SubCell)Exts.ParseByte(parts[4])));
 
 					var actorCount = map.ActorDefinitions.Count;