gistfile1.hs

deDupItems' :: [Item] -> [Item] -> IdCountMap -> ([Item], IdCountMap)
deDupItems' (item:items) keptItems seenMap =
    case getDeliciousUrlId item of
      Nothing -> deDupItems' items keptItems seenMap -- We didn't get an id, so drop it and move on
      Just anId -> deDupItems' items itemsToKeep (Map.insert anId (count + 1) seenMap)
          where
            count = Map.findWithDefault defaultValue anId seenMap
            itemsToKeep = if count > 0 then keptItems else keptItems ++ [item]

deDupItems' [] keptItems seenMap =  (keptItems, seenMap)