X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FTSN%2FXmlImport.hs;h=4300e87ff4d6182475fcda1f30071b2082a43030;hb=59d56f0ae0da1d4b1898b3c7536ae38473306319;hp=3791ab56ef19add5ec4d0638d94a4e26cec51b51;hpb=a913a63f7679b59f9b650619e8fbfc6e81f3f8d3;p=dead%2Fhtsn-import.git

diff --git a/src/TSN/XmlImport.hs b/src/TSN/XmlImport.hs
index 3791ab5..4300e87 100644
--- a/src/TSN/XmlImport.hs
+++ b/src/TSN/XmlImport.hs
@@ -26,3 +26,18 @@ class (FromXml a, PersistEntity (Db a)) => XmlImport a where
                   => a
                   -> m ( Either (AutoKey (Db a)) (AutoKey (Db a)) )
   insertByAll_xml x = insertByAll (from_xml x)
+
+
+  -- | Try to insert the given object and get its primary key
+  --   back. Or, if there's a unique constraint violation, get the
+  --   primary key of the unique thing already present.
+  --
+  --   Note: we can switch to using fmap here as soon as Functor is a
+  --   superclass of Monad (PersistBackend is a Monad).
+  --
+  insert_xml_or_select :: (PersistBackend m)
+                       => a
+                       -> m (AutoKey (Db a))
+  insert_xml_or_select x = do
+    tmp <- insertByAll_xml x
+    return $ (either id id) tmp