avoid direct use of PU constructor

Building picklers from predefined combinators is more robust against possible future API changes.

pontarius-xmpp.cabal

@@ -59,7 +59,7 @@ Library
                , void              >=0.5.5
                , xml-types         >=0.3.1
                , xml-conduit       >=1.0
-               , xml-picklers      >=0.3.2
+               , xml-picklers      >=0.3.3
   Exposed-modules: Network.Xmpp
                  , Network.Xmpp.IM
                  , Network.Xmpp.Internal

source/Network/Xmpp/Marshal.hs

@@ -2,7 +2,9 @@
 -- respectively. By convensions, pickler/unpickler ("PU") function names start
 -- out with "xp".
 
-{-# Language OverloadedStrings, ViewPatterns, NoMonomorphismRestriction #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE NoMonomorphismRestriction #-}
 
 {-# OPTIONS_HADDOCK hide #-}
 
@@ -274,7 +276,8 @@ xpStreamFeatures = ("xpStreamFeatures","") <?> xpWrap
              "{urn:ietf:params:xml:ns:xmpp-sasl}mechanism" (xpContent xpId))
 
 xpJid :: PU Text Jid
-xpJid = PU { unpickleTree = \input -> case jidFromText input of
+xpJid = ("xpJid", "") <?>
-                  Nothing -> UnpickleError $ ErrorMessage "Could not parse JID."
+        xpPartial ( \input -> case jidFromText input of
-                  Just jid -> Result jid Nothing
+                                   Nothing -> Left "Could not parse JID."
-           , pickleTree = \input -> jidToText input }
+                                   Just jid -> Right jid)
+                  jidToText