proc comes with 2 free silos; fix silo/proc prereq

OpenRA.Mods.RA/HasUnitOnBuild.cs

@@ -19,36 +19,35 @@
 #endregion
 
 using OpenRA.Traits;
-
+using System.Linq;
 namespace OpenRA.Mods.RA
 {
-	class HasUnitOnBuildInfo : ITraitInfo
+	public class FreeActorInfo : ITraitInfo
 	{
-		public readonly string Unit = null;
+		public readonly string Actor = null;
 		public readonly string InitialActivity = null;
 		public readonly int2 SpawnOffset = int2.Zero;
 		public readonly int Facing = 0;
 		
-		public object Create( Actor self ) { return new HasUnitOnBuild(self); }
+		public object Create( Actor self ) { return new FreeActor(self, this); }
 	}
 
-	public class HasUnitOnBuild
+	public class FreeActor
 	{
-		
-		public HasUnitOnBuild(Actor self)
-		{
-			var info = self.Info.Traits.Get<HasUnitOnBuildInfo>();
-			
+		public FreeActor(Actor self, FreeActorInfo info)
+		{			
 			self.World.AddFrameEndTask(
 				w =>
 				{
-					var unit = w.CreateActor(info.Unit, self.Location 
+					var a = w.CreateActor(info.Actor, self.Location 
 						+ info.SpawnOffset, self.Owner);
-					var unitTrait = unit.traits.Get<Unit>();
-					unitTrait.Facing = info.Facing;
+					var unit = a.traits.WithInterface<Unit>().FirstOrDefault();
+					
+					if (unit != null)
+						unit.Facing = info.Facing;
 
 					if (info.InitialActivity != null)
-						unit.QueueActivity(Game.CreateObject<IActivity>(info.InitialActivity));
+						a.QueueActivity(Game.CreateObject<IActivity>(info.InitialActivity));
 				});
 		}
 	}

OpenRA.Mods.RA/OpenRA.Mods.RA.csproj

@@ -179,6 +179,7 @@
     <Compile Include="GainsExperience.cs" />
     <Compile Include="GivesExperience.cs" />
     <Compile Include="Invulnerable.cs" />
+    <Compile Include="ReplaceWithActor.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRA.FileFormats\OpenRA.FileFormats.csproj">

OpenRA.Mods.RA/ReplaceWithActor.cs

@@ -0,0 +1,43 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
+ * This file is part of OpenRA.
+ * 
+ *  OpenRA is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  OpenRA is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU General Public License
+ *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class ReplaceWithActorInfo : ITraitInfo
+	{
+		public readonly string Actor = null;
+		public object Create(Actor self) { return new ReplaceWithActor(self, this); } 
+	}
+
+	class ReplaceWithActor
+	{
+		public ReplaceWithActor(Actor self, ReplaceWithActorInfo info)
+		{
+			self.World.AddFrameEndTask(w =>
+			{
+				w.Remove(self);
+				w.CreateActor(info.Actor, self.Location, self.Owner);
+			});
+		}
+	}
+}