diff --git a/src/structs.h b/src/structs.h
index 5d1496f..8a94fc1 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -4106,6 +4106,9 @@
     EXPR_MULT,		// *
     EXPR_DIV,		// /
     EXPR_REM,		// %
+    // used with ISN_ADDLIST
+    EXPR_COPY,		// create new list
+    EXPR_APPEND,	// append to first list
 } exprtype_T;
 
 /*