Hacker news reader from the command line

hn.hs

import Network.HTTP
import Text.HTML.TagSoup
import System
import System.Process
import Control.Monad
import IO

hackerNewsRSSFeedURL = "http://news.ycombinator.com/rss"
fileURLCache         = ".hnCache"

getUrl :: String -> IO (String)
getUrl url = simpleHTTP(getRequest url) >>= getResponseBody

getTitles :: [Tag String] -> [String]
getTitles = getTextFromTagsWithName "title"

getLinks :: [Tag String] -> [String]
getLinks  = getTextFromTagsWithName "link"

getTextFromTagsWithName :: String -> [Tag String] -> [String]
getTextFromTagsWithName _ []        = []
getTextFromTagsWithName name (x:xs) =
  case isTagOpenName name x of
     True  -> getText xs : getTextFromTagsWithName name xs
     False -> getTextFromTagsWithName name xs

getText :: [Tag String] -> String
getText []     = ""
getText (x:xs) = fromTagText x

displayWithKey :: [String] -> [String]
displayWithKey []     = []
displayWithKey (x:xs) = zipWith (\ a b -> (show a) ++ " - " ++ b) [0..] (x:xs)

runAction :: [String] -> IO()
runAction []     = do
  -- Fetch the feed and display the indexed titles
  rawRSS <- getUrl hackerNewsRSSFeedURL
  tags   <- return $ parseTags rawRSS
  mapM_ (\ x -> hPutStrLn stdout x) $ displayWithKey $ getTitles tags

  -- Store the links
  store  <- openFile fileURLCache WriteMode
  mapM_ (\ x -> hPutStrLn store x) $ getLinks tags
  hClose store

runAction [(x:xs)] = do
  urls    <- readFile fileURLCache
  pHandle <- system $ getCommand (x:xs) urls
  hPutStrLn stdout "done"

getCommand (x:xs) (y:ys) = "open " ++ lines (y:ys) !! (read (x:xs))

main = do
  args   <- getArgs
  runAction args