diff --git a/src/ops.c b/src/ops.c
index 9695d9d..82a7595 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -780,7 +780,7 @@
     if (expr_copy == NULL)
 	return NULL;
 
-    rv = eval_to_string(expr_copy, NULL);
+    rv = eval_to_string(expr_copy, NULL, TRUE);
     vim_free(expr_copy);
     return rv;
 }