diff --git a/Types.hs b/Types.hs
index 6be0223..e1c700e 100644
--- a/Types.hs
+++ b/Types.hs
@@ -15,7 +15,9 @@ type Extensions = [Extension]
 type Grandfathered = String
 type Privateuse = [String]
 
-data Tag = Tag Language Extlang Script Region Variants Extensions | GF Grandfathered | Priv Privateuse deriving (Show, Eq) 
--- TODO: warning, Eq must 
--- be redefined because it needs to take into account case-insensitivity and 
--- (maybe) canonicalization
+data Tag = Tag Language Extlang Script Region Variants Extensions | GF Grandfathered | Priv Privateuse deriving (Show) 
+-- Warning, Eq must be redefined because it needs to take into account
+-- case-insensitivity and (maybe) canonicalization (see issue #10).
+-- Complicated because Tag is not a string. Sopmething like:
+-- instance Eq Tag where
+--  a == b = (Language a) == (Language b) ...