diff --git a/lib/regexp-examples/constants.rb b/lib/regexp-examples/constants.rb
index ea4f480..53fd4f2 100644
--- a/lib/regexp-examples/constants.rb
+++ b/lib/regexp-examples/constants.rb
@@ -35,6 +35,9 @@ module CharSets
     Lower        = Array('a'..'z')
     Upper        = Array('A'..'Z')
     Digit        = Array('0'..'9')
+    # Note: Punct should also include the following chars: $ + < = > ^ ` | ~
+    # I.e. Punct = %w(! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \\ ] ^ _ ` { | } ~)
+    # However, due to a ruby bug (!!) these do not work properly at the moment!
     Punct        = %w(! " # % & ' ( ) * , - . / : ; ? @ [ \\ ] _ { })
     Hex          = Array('a'..'f') | Array('A'..'F') | Digit
     Word         = Lower | Upper | Digit | ['_']