Add last Lua type: userdata. Changed LInstance to inherit from LUserData,

and changed instanceof/casts to LInstance to use LUserData instead. This
should enable various add-ons to be compatible without knowing much, or
anything, about each other.

src/addon/java/lua/addon/luajava/CoerceLuaToJava.java

@@ -11,6 +11,7 @@ import lua.value.LInteger;
 import lua.value.LNil;
 import lua.value.LNumber;
 import lua.value.LString;
+import lua.value.LUserData;
 import lua.value.LValue;
 
 public class CoerceLuaToJava {
@@ -69,15 +70,15 @@ public class CoerceLuaToJava {
 				return value.luaAsString();
 			} 
 			public int score(LValue value) {
-				if ( value instanceof LInstance )
+				if ( value instanceof LUserData )
 					return 0;
 				return 1;
 			}
 		};
 		Coercion objectCoercion = new Coercion() {
 			public Object coerce(LValue value) {
-				if ( value instanceof LInstance )
+				if ( value instanceof LUserData )
-					return ((LInstance)value).instance;
+					return ((LUserData)value).m_instance;
 				if ( value instanceof LString )
 					return value.luaAsString();
 				if ( value instanceof LInteger )
@@ -116,8 +117,8 @@ public class CoerceLuaToJava {
 		Coercion co = COERCIONS.get( type );
 		if ( co != null )
 			return co.coerce( v );
-		if ( v instanceof LInstance )
+		if ( v instanceof LUserData )
-			return ((LInstance) v).instance;
+			return ((LUserData) v).m_instance;
 		return v;
 	}
 
@@ -146,8 +147,8 @@ public class CoerceLuaToJava {
 			Coercion co = COERCIONS.get( c );
 			if ( co != null ) {
 				score += co.score( v );
-			} else if ( v instanceof LInstance ) {
+			} else if ( v instanceof LUserData ) {
-				Object o = ((LInstance) v).instance;
+				Object o = ((LUserData) v).m_instance;
 				if ( ! c.isAssignableFrom(o.getClass()) )
 						score += 0x10000;
 			} else {

src/addon/java/lua/addon/luajava/LuaJava.java

@@ -14,6 +14,7 @@ import lua.GlobalState;
 import lua.value.LFunction;
 import lua.value.LString;
 import lua.value.LTable;
+import lua.value.LUserData;
 import lua.value.LValue;
 
 public final class LuaJava extends LFunction {
@@ -96,46 +97,39 @@ public final class LuaJava extends LFunction {
 			call.adjustTop(base + nresults);
 	}
 	
-	public static class LInstance extends LValue {
+	public static class LInstance extends LUserData {
-		Object instance;
 		private Class clazz;
 		public LInstance(Object o, Class clazz) {
-			this.instance = o;
+			super(o);
 			this.clazz = clazz;
 		}
-		public String luaAsString() {
-			return instance.toString();
-		}
 		public void luaGetTable(CallFrame call, int base, LValue table, LValue key) {
 			final String s = key.luaAsString();
 			try {
 				Field f = clazz.getField(s);
-				Object o = f.get(instance);
+				Object o = f.get(m_instance);
 				LValue v = CoerceJavaToLua.coerce( o );
 				call.stack[base] = v;
 				call.top = base + 1;
 			} catch (NoSuchFieldException nsfe) {
-				call.stack[base] = new LMethod(instance,clazz,s);
+				call.stack[base] = new LMethod(m_instance,clazz,s);
 				call.top = base + 1;
 			} catch (Exception e) {
 				throw new RuntimeException(e);
 			}
 		}
 		public void luaSetTable(CallFrame call, int base, LValue table, LValue key, LValue val) {
-			Class c = instance.getClass();
+			Class c = m_instance.getClass();
 			String s = key.luaAsString();
 			try {
 				Field f = c.getField(s);
 				Object v = CoerceLuaToJava.coerceArg(val, f.getType());
-				f.set(instance,v);
+				f.set(m_instance,v);
 				call.top = base;
 			} catch (Exception e) {
 				throw new RuntimeException(e);
 			}
 		}
-		public LString luaGetType() {
-			return new LString("userdata");
-		}
 		
 	}
 

src/main/java/lua/value/LUserData.java

@@ -0,0 +1,28 @@
+package lua.value;
+
+public class LUserData extends LValue {
+	public static final LString TYPE_NAME = new LString("userdata");
+	
+	public final Object m_instance;
+	
+	public LUserData(Object obj) {
+		m_instance = obj;
+	}
+	
+	public String luaAsString() {
+		return m_instance.toString();
+	}
+	
+	public boolean equals(Object obj) {
+		return (this == obj) ||
+			(obj instanceof LUserData && this.m_instance == ((LUserData) obj).m_instance);
+	}
+	
+	public int hashCode() {
+		return System.identityHashCode( m_instance );
+	}
+
+	public LString luaGetType() {
+		return TYPE_NAME;
+	}
+}