ask3.hs

import Text.Regex

mail :: Regex
mail = mkRegex "(([a-zA-Z0-9]+[ \t]+)?[a-zA-Z0-9]+[ \t]+)?((mailto://)?[a-zA-Z0-9]+@[a-zA-Z0-9]+(\\.[a-zA-Z0-9]+)+)"

mainmatch s = case m of {
        Nothing -> [];
        Just (pre, mm, post, sub) -> (sub!!0, sub!!2):mainmatch post
} where m = Text.Regex.matchRegexAll mail s

htmlformat s = "<ul>\n" ++ (concat $ map htmlformatitem s) ++ "</ul>"
htmlformatitem (name, mail) = if name == ""
        then "<li>\n\n\t<a href=\"" ++ mail ++ "\">\n\t " ++ mail ++ "\n\t\t</a></li>\n"
        else "<li>" ++ name ++ ", \n\t<a href=\"" ++ mail ++ "\">\n\t " ++ mail ++ "\n\t\t</a></li>\n"

main = do
      s <- readFile "names"
      let sout = htmlformat $ mainmatch s in
         writeFile "names.html" sout