    module Main where

    import IO
    import List (isSuffixOf)

    import Text.XML.HaXml.ParseLazy      (xmlParse)
    import Text.XML.HaXml.Html.ParseLazy (htmlParse)
    import Text.XML.HaXml.Wrappers       (fix2Args)
    import Text.PrettyPrint.HughesPJ     (render)
    import qualified Text.XML.HaXml.Pretty      as XmlPP
    import qualified Text.XML.HaXml.Html.Pretty as HtmlPP

    -- 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,format) =
             if ".html" `isSuffixOf` inf || ".htm" `isSuffixOf` inf
               then (htmlParse inf, HtmlPP.document)
               else (xmlParse  inf, XmlPP.document)
      in
      do ( mapM_ (hPutStrLn o) . lines . render . format . parse) content
         hFlush o