src/TSN/Picklers.hs

   1 -- | (Un)picklers for data types present in The Sports Network XML
   2 --   feed.
   3 --
   4 module TSN.Picklers (
   5   xp_date )
   6 where
   7
   8 import Data.Time.Clock ( UTCTime )
   9 import Data.Time.Format ( formatTime, parseTime )
  10 import System.Locale ( defaultTimeLocale )
  11 import Text.Read ( readMaybe )
  12 import Text.XML.HXT.Arrow.Pickle (
  13   XmlPickler(..),
  14   xpText,
  15   xpWrapMaybe )
  16 import Text.XML.HXT.Arrow.Pickle.Xml ( PU )
  17
  18 instance XmlPickler Bool where
  19   xpickle =
  20     (to_bool, from_bool) `xpWrapMaybe` xpText
  21     where
  22       to_bool :: String -> Maybe Bool
  23       to_bool = readMaybe
  24
  25       from_bool :: Bool -> String
  26       from_bool = show
  27
  28
  29 -- | (Un)pickle a UTCTime without the time portion.
  30 --
  31 xp_date :: PU UTCTime
  32 xp_date =
  33   (to_date, from_date) `xpWrapMaybe` xpText
  34   where
  35     format = "%-m/%-d/%Y"
  36
  37     to_date :: String -> Maybe UTCTime
  38     to_date = parseTime defaultTimeLocale format
  39
  40     from_date :: UTCTime -> String
  41     from_date = formatTime defaultTimeLocale format