--- a/core/src/luan/impl/UnmExpr.java	Tue Apr 28 22:49:33 2015 -0600
+++ b/core/src/luan/impl/UnmExpr.java	Wed Apr 29 07:04:40 2015 -0600
@@ -5,6 +5,7 @@
 import luan.LuanException;
 import luan.LuanSource;
 import luan.LuanBit;
+import luan.LuanTable;
 
 
 // unary minus
@@ -20,9 +21,11 @@
 		if( n != null )
 			return -n.doubleValue();
 		LuanBit bit = luan.bit(se);
-		LuanFunction fn = bit.getHandlerFunction("__unm",o);
-		if( fn != null ) {
-			return Luan.first(bit.call(fn,"__unm",new Object[]{o}));
+		if( o instanceof LuanTable ) {
+			LuanFunction fn = bit.getHandlerFunction("__unm",(LuanTable)o);
+			if( fn != null ) {
+				return Luan.first(bit.call(fn,"__unm",new Object[]{o}));
+			}
 		}
 		throw bit.exception("attempt to perform arithmetic on a "+Luan.type(o)+" value");
 	}