-- feed.
--
module TSN.Picklers (
- xp_date )
+ xp_date,
+ xp_team_id )
where
+-- System imports.
import Data.Time.Clock ( UTCTime )
import Data.Time.Format ( formatTime, parseTime )
import System.Locale ( defaultTimeLocale )
-import Text.Read ( readMaybe )
import Text.XML.HXT.Arrow.Pickle (
- XmlPickler(..),
xpText,
xpWrapMaybe )
import Text.XML.HXT.Arrow.Pickle.Xml ( PU )
-instance XmlPickler Bool where
- xpickle =
- (to_bool, from_bool) `xpWrapMaybe` xpText
- where
- to_bool :: String -> Maybe Bool
- to_bool = readMaybe
-
- from_bool :: Bool -> String
- from_bool = show
-
-- | (Un)pickle a UTCTime without the time portion.
--
from_date :: UTCTime -> String
from_date = formatTime defaultTimeLocale format
+
+
+-- | Parse a team_id. These are (so far!) three characters long, and
+-- not necessarily numeric. For simplicity, we return a 'String'
+-- rather than e.g. a @(Char, Char, Char)@. But unpickling will fail
+-- if the team_id is longer than three characters.
+--
+xp_team_id :: PU String
+xp_team_id =
+ (to_team_id, from_team_id) `xpWrapMaybe` xpText
+ where
+ to_team_id :: String -> Maybe String
+ to_team_id s
+ | length s <= 3 = Just s
+ | otherwise = Nothing
+
+ from_team_id :: String -> String
+ from_team_id = id