diff --git a/doc/example/url.treerack b/doc/example/url.treerack
index 13ceb7d..1c0fb44 100644
--- a/doc/example/url.treerack
+++ b/doc/example/url.treerack
@@ -58,8 +58,12 @@ path-absolute                            = "/" (segment-non-zero ("/" segment)*)
 path-rootless                            = segment-non-zero ("/" segment)*;
 path-noscheme                            = segment-non-zero-no-colon ("/" segment)*;
 path-empty                               = "";
-query                                    = (path-char | "/" | "?")*;
-fragment                                 = (path-char | "/" | "?")*;
+
+// query:
+query = (path-char | "/" | "?")*;
+
+// fragment:
+fragment = (path-char | "/" | "?")*;
 
 // composed together:
 authority-rfc:alias:failpass      = (userinfo "@")? host-rfc;