add Default instance for InstantMessage and IMPresence

source/Network/Xmpp/IM/Message.hs

@@ -3,14 +3,14 @@
 
 module Network.Xmpp.IM.Message where
 
+import Data.Default
+import Data.Function
+import Data.List
 import Data.Text (Text)
 import Data.XML.Pickle
 import Data.XML.Types
 import Network.Xmpp.Marshal
 import Network.Xmpp.Types
-import Data.List
-import Data.Function
-
 
 data MessageBody = MessageBody { bodyLang    :: Maybe LangTag
                                , bodyContent :: Text
@@ -36,6 +36,9 @@ instantMessage = InstantMessage { imThread  = Nothing
                                 , imBody    = []
                                 }
 
+instance Default InstantMessage where
+    def = instantMessage
+
 -- | Get the IM specific parts of a message. Returns 'Nothing' when the received
 -- payload is not valid IM data.
 getIM :: Message -> Maybe InstantMessage

source/Network/Xmpp/IM/Presence.hs

@@ -4,10 +4,11 @@
 
 module Network.Xmpp.IM.Presence where
 
-import           Data.Text (Text)
-import           Data.XML.Pickle
-import           Data.XML.Types
-import           Network.Xmpp.Types
+import Data.Default
+import Data.Text (Text)
+import Data.XML.Pickle
+import Data.XML.Types
+import Network.Xmpp.Types
 
 data ShowStatus = StatusAway
                 | StatusChat
@@ -38,7 +39,11 @@ imPresence = IMP { showStatus = Nothing
                  , priority   = Nothing
                  }
 
+instance Default IMPresence where
+    def = imPresence
 
+-- | Try to extract RFC6121 IM presence information from presence stanza
+-- Returns Nothing when the data is malformed, (Just IMPresence) otherwise
 getIMPresence :: Presence -> Maybe IMPresence
 getIMPresence pres = case unpickle xpIMPresence (presencePayload pres) of
     Left _ -> Nothing