diff --git a/src/structs.h b/src/structs.h
index 612c26c..a367d05 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -4152,6 +4152,8 @@
     EXPR_MULT,		// *
     EXPR_DIV,		// /
     EXPR_REM,		// %
+    EXPR_LSHIFT,	// <<
+    EXPR_RSHIFT,	// >>
     // used with ISN_ADDLIST
     EXPR_COPY,		// create new list
     EXPR_APPEND,	// append to first list