X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FFeedHosts.hs;h=58f82f57ae9d4ad29cec82c59a5ac29f02952cb2;hb=HEAD;hp=43bab176aa67efeaba8e6a045aa1ae9d8057481d;hpb=d4d924b26e451aec9ad84b6d9d376ba2aeab3422;p=dead%2Fhtsn.git

diff --git a/src/FeedHosts.hs b/src/FeedHosts.hs
index 43bab17..58f82f5 100644
--- a/src/FeedHosts.hs
+++ b/src/FeedHosts.hs
@@ -1,25 +1,38 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 
 -- | A newtype around a list of Strings which represent the feed
--- hosts. This is all to avoid an orphan instance of Configured for
--- [String] if we had defined one in e.g. OptionalConfiguration.
+--   hosts. This is all to avoid an orphan instance of Configured for
+--   [String] if we had defined one in e.g. 'OptionalConfiguration'.
+--
+--   This was placed under the \"TSN\" namespace because its Default
+--   instance is specific to TSN, even though otherwise it's just a
+--   list of strings.
 --
 module FeedHosts
 where
 
 -- DC is needed only for the DCT.Configured instance of String.
 import qualified Data.Configurator as DC()
-import qualified Data.Configurator.Types as DCT
+import qualified Data.Configurator.Types as DCT (
+  Configured,
+  Value( List ),
+  convert )
 import Data.Data (Data)
 import System.Console.CmdArgs.Default (Default(..))
 import Data.Typeable (Typeable)
 
 
+-- | A (wrapper around a) list of hostnames that supply the XML feed.
+--
 newtype FeedHosts =
   FeedHosts { get_feed_hosts :: [String] }
     deriving (Data, Show, Typeable)
 
 
+-- | The default list of feed hosts. These were found by checking
+--   PTR records in the neighborhood of the IP address in use. There
+--   is a feed4.sportsnetwork.com, but it was not operational when
+--   this was written.
 instance Default FeedHosts where
   def = FeedHosts ["feed1.sportsnetwork.com",
                    "feed2.sportsnetwork.com",
@@ -27,11 +40,18 @@ instance Default FeedHosts where
 
 
 instance DCT.Configured FeedHosts where
+  -- | This allows us to read a FeedHosts object out of a Configurator
+  --   config file. By default Configurator wouldn't know what to do,
+  --   so we have to tell it that we expect a list, and if that list
+  --   has strings in it, we can apply the FeedHosts constructor to
+  --   it.
   convert (DCT.List xs) =
+    -- mapM gives us a Maybe [String] here.
     fmap FeedHosts (mapM convert_string xs)
     where
       convert_string :: DCT.Value -> Maybe String
       convert_string = DCT.convert
 
+  -- If we read anything other than a list of values out of the file,
+  -- fail.
   convert _ = Nothing
-