Lazy SAX parser

parse.hs

-- http://hackage.haskell.org/packages/archive/hexpat/0.19.7/doc/html/Text-XML-Expat-SAX.html#g:2
-- http://stackoverflow.com/questions/2292729/with-haskell-how-do-i-process-large-volumes-of-xml

import qualified Data.ByteString.Lazy as BSL
import Prelude hiding (readFile)
import Text.XML.Expat.SAX 

main = do
   -- I need a ByteString 
    contents <- BSL.readFile "schedules.xml"
    let events = parse defaultParseOptions contents
    print $ map getTMSId $ filter isEvent events
    putStrLn "DONE"

isEvent :: SAXEvent String String -> Bool 
isEvent (StartElement "event" as) = True
isEvent _ = False

getTMSId :: SAXEvent String String -> Maybe String
getTMSId (StartElement _ as) = lookup "TMSId" as