diff --git a/README.md b/README.md
index 10c718a..1e05c68 100644
--- a/README.md
+++ b/README.md
@@ -141,4 +141,6 @@ escline := '\' newline
 linespace := newline | ws
 
 newline := (CR LF) | LF
+
+ws := bom | whitespace-chars (todo)
 ```