diff --git a/src/eval.c b/src/eval.c
index 8f6fcf3..aff284e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -345,6 +345,7 @@
     {VV_NAME("mouse_win",	 VAR_NUMBER), 0},
     {VV_NAME("mouse_lnum",	 VAR_NUMBER), 0},
     {VV_NAME("mouse_col",	 VAR_NUMBER), 0},
+    {VV_NAME("operator",	 VAR_STRING), VV_RO},
 };
 
 /* shorthand */