    module Main where

    import IO
    import List   (isSuffixOf)

    import Text.XML.HaXml.Parse      (xmlParse)
    import Text.XML.HaXml.Html.Parse (htmlParse)
    import Text.XML.HaXml.Pretty     (document)
    import Text.XML.HaXml.Wrappers   (fix2Args)
    import Text.PrettyPrint.HughesPJ (render)

    -- This is just a trivial application that reads an XML or HTML document
    -- from a file (or stdin) and writes it back to another file (or stdout).
    -- It demonstrates the behaviour of the parser and pretty-printer,
    -- including any shortcomings they may have.

    main :: IO ()
    main =
      fix2Args >>= \(inf,outf)->
      ( if inf=="-" then getContents
        else readFile inf )            >>= \content->
      ( if outf=="-" then return stdout
        else openFile outf WriteMode ) >>= \o->
      let parse = if ".html" `isSuffixOf` inf || ".htm" `isSuffixOf` inf
                  then htmlParse inf else xmlParse inf
      in
      do ( hPutStrLn o . render . document . parse) content
         hFlush o