-- Haskell types to support the language tags

module Types where 

type Language = String 
type Extlang = Maybe String -- Only one extlang authorized
type Script = Maybe String
type Region = Maybe String
type Singleton = Char
type Variants = [Variant]
type Variant = String
type Extension = (Singleton, [String])
type Extensions = [Extension]

type Grandfathered = String
type Privateuse = [String]

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) ...