Hide list comp variables and support set comprehensions
diff --git a/Include/opcode.h b/Include/opcode.h
index 662fbb4..5fbb037 100644
--- a/Include/opcode.h
+++ b/Include/opcode.h
@@ -21,6 +21,7 @@
 
 #define UNARY_INVERT	15
 
+#define SET_ADD	17
 #define LIST_APPEND	18
 #define BINARY_POWER	19