--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/luan/interp/UpValue.java	Fri Dec 14 05:40:35 2012 +0000
@@ -0,0 +1,54 @@
+package luan.interp;
+
+
+final class UpValue {
+	private Object[] stack;
+	private int index;
+
+	UpValue(Object[] stack,int index) {
+		this.stack = stack;
+		this.index = index;
+	}
+
+	Object get() {
+		return stack[index];
+	}
+
+	void set(Object value) {
+		stack[index] = value;
+	}
+
+	void close() {
+		stack = new Object[]{get()};
+		index = 0;
+	}
+
+	static interface Getter {
+		public UpValue get(LuaStateImpl lua);
+	}
+
+	static final class StackGetter implements Getter {
+		private final int index;
+
+		StackGetter(int index) {
+			this.index = index;
+		}
+
+		public UpValue get(LuaStateImpl lua) {
+			return lua.getUpValue(index);
+		}
+	}
+
+	static final class NestedGetter implements Getter {
+		private final int index;
+
+		NestedGetter(int index) {
+			this.index = index;
+		}
+
+		public UpValue get(LuaStateImpl lua) {
+			return lua.closure().upValues[index];
+		}
+	}
+
+}