+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverloadedStrings #-}
-- | The program will parse ~/.twatrc for any available configuration
-- the merged OptionalCfgs.
--
-module OptionalConfiguration
+module OptionalConfiguration (
+ OptionalCfg(..),
+ from_rc
+ )
where
-import Data.Monoid (Monoid(..))
import qualified Data.Configurator as DC
+import qualified Data.Configurator.Types as DCT
+import Data.Data (Data)
+import Data.Maybe (fromMaybe)
+import Data.Monoid (Monoid(..))
+import Data.Typeable (Typeable)
--- The same as Cfg, except everything is optional. It's easy to merge
--- two of these by simply dropping the Nothings in favor of the Justs.
+-- | The same as Cfg, except everything is optional. It's easy to
+-- merge two of these by simply dropping the Nothings in favor of
+-- the Justs. The 'usernames' are left un-maybed so that cmdargs
+-- can parse more than one of them.
+--
data OptionalCfg =
OptionalCfg { consumer_key :: Maybe String,
consumer_secret :: Maybe String,
sendmail_path :: Maybe String,
from_address :: Maybe String,
to_address :: Maybe String,
- verbose :: Maybe Bool }
+ verbose :: Maybe Bool,
+ usernames :: [String] }
+ deriving (Show, Data, Typeable)
instance Monoid OptionalCfg where
mempty = OptionalCfg
Nothing
Nothing
Nothing
+ []
cfg1 `mappend` cfg2 =
OptionalCfg
(merge (from_address cfg1) (from_address cfg2))
(merge (to_address cfg1) (to_address cfg2))
(merge (verbose cfg1) (verbose cfg2))
+ all_usernames
where
merge :: (Maybe a) -> (Maybe a) -> (Maybe a)
merge Nothing Nothing = Nothing
merge Nothing (Just x) = Just x
merge (Just _) (Just y) = Just y
+ -- Use only the latter usernames if there are any.
+ all_usernames = if (null (usernames cfg2))
+ then (usernames cfg1)
+ else (usernames cfg2)
+
+instance DCT.Configured [String] where
+ convert (DCT.List xs) =
+ mapM convert_string xs
+ where
+ convert_string :: DCT.Value -> Maybe String
+ convert_string = DCT.convert
+
+ convert _ = Nothing
+
from_rc :: IO OptionalCfg
from_rc = do
cfg <- DC.load [ DC.Optional "$(HOME)/.twatrc" ]
cfg_from_address <- DC.lookup cfg "from"
cfg_to_address <- DC.lookup cfg "to"
cfg_verbose <- DC.lookup cfg "verbose"
+ cfg_usernames <- DC.lookup cfg "usernames"
+
return $ OptionalCfg
cfg_consumer_key
cfg_consumer_secret
cfg_from_address
cfg_to_address
cfg_verbose
-
+ (fromMaybe [] cfg_usernames)