Introduce NamedHotkey type.

OpenRA.Game/FieldLoader.cs

@@ -273,6 +273,10 @@ namespace OpenRA
 
 				return InvalidValueAction(value, fieldType, fieldName);
 			}
+			else if (fieldType == typeof(NamedHotkey))
+			{
+				return new NamedHotkey(value, Game.Settings.Keys);
+			}
 			else if (fieldType == typeof(WDist))
 			{
 				WDist res;

OpenRA.Game/Input/NamedHotkey.cs

@@ -0,0 +1,49 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you 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. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA
+{
+	/// <summary>
+	/// A reference to either a named hotkey (defined in the game settings) or a statically assigned hotkey
+	/// </summary>
+	public class NamedHotkey
+	{
+		static readonly Func<Hotkey> Invalid = () => Hotkey.Invalid;
+
+		readonly Func<Hotkey> getValue;
+
+		public NamedHotkey()
+		{
+			getValue = Invalid;
+		}
+
+		public NamedHotkey(string name, KeySettings settings)
+		{
+			// Try parsing the value as a reference to a named hotkey
+			getValue = settings.GetHotkeyReference(name);
+
+			if (getValue == null)
+			{
+				// Try parsing the value as a normal (static) hotkey
+				var staticKey = Hotkey.Invalid;
+				Hotkey.TryParse(name, out staticKey);
+				getValue = () => staticKey;
+			}
+		}
+
+		public Hotkey GetValue()
+		{
+			return getValue();
+		}
+	}
+}

OpenRA.Game/OpenRA.Game.csproj

@@ -223,6 +223,7 @@
     <Compile Include="Input\InputHandler.cs" />
     <Compile Include="Input\Keycode.cs" />
     <Compile Include="Input\Hotkey.cs" />
+    <Compile Include="Input\NamedHotkey.cs" />
     <Compile Include="Graphics\PlatformInterfaces.cs" />
     <Compile Include="Sound\Sound.cs" />
     <Compile Include="Sound\SoundDevice.cs" />

OpenRA.Game/Settings.cs

@@ -307,6 +307,15 @@ namespace OpenRA
 				Expression.Field(keySettings, "{0}{1:D2}Key".F(prefix, i + 1)), keySettings).Compile());
 		}
 
+		internal Func<Hotkey> GetHotkeyReference(string name)
+		{
+			var field = typeof(KeySettings).GetField(name + "Key");
+			if (field == null)
+				return null;
+
+			return () => (Hotkey)field.GetValue(this);
+		}
+
 		public Hotkey GetProductionHotkey(int index)
 		{
 			return GetKey(ProductionKeys, index);