generator/Site/Lang.hs

   1 module Site.Lang where
   2
   3 import Data.Aeson (FromJSON (parseJSON), withText)
   4 import Data.Text qualified as Text
   5 import Relude
   6 import Prelude ()
   7
   8 -- * Type 'Lang'
   9 data Lang
  10   = LangDe
  11   | LangEn
  12   | LangFr
  13   | LangJp
  14   deriving (Bounded, Show, Enum, Eq)
  15
  16 langText :: IsString a => Lang -> a
  17 langText = \case
  18   LangDe -> "Deutsch"
  19   LangEn -> "English"
  20   LangFr -> "français"
  21   LangJp -> "日本語"
  22
  23 parseLang :: Text -> Maybe Lang
  24 parseLang = \case
  25   "de" -> Just LangDe
  26   "en" -> Just LangEn
  27   "fr" -> Just LangFr
  28   "jp" -> Just LangJp
  29   _ -> Nothing
  30
  31 instance FromJSON Lang where
  32   parseJSON =
  33     withText "Lang" $
  34       maybe (fail "expected a Lang") pure
  35         . parseLang
  36
  37 textOfLang :: Lang -> Text
  38 textOfLang = Text.drop 4 . Text.toLower . show