Haskell version of http://eax.me/scala/

twitsearch.hs

import Data.Aeson
import Network.HTTP
 
import System.Environment (getArgs)
import Control.Monad (mapM_)
 
import Data.Maybe (fromMaybe)
import qualified Data.ByteString.Lazy.Char8 as LBS
import qualified Data.Text as T
import qualified Data.HashMap.Strict as HM
import qualified Data.Vector as V
 
main = do
    args <- getArgs
    case args of
        [q] -> fetchTweets q
        _   -> putStrLn "twitsearch <query>"

fetchTweets q = do
    let req = getRequest $ "http://search.twitter.com/search.json?" ++ urlEncodeVars [("q", q)]
    body <- simpleHTTP req >>= getResponseBody
    let doc = fromMaybe Null . decode . LBS.pack $ body

    let tweets = mapV (asString . key "text") . key "results" $ doc
    mapM_ putStrLn tweets

-- Ad-Hoc JSON queries
key :: String -> Value -> Value
key k (Object o) = maybe Null id (HM.lookup (T.pack k) o)
key k _          = Null

mapV :: (Value -> a) -> Value -> [a]
mapV f (Array l) = map f (V.toList l)
mapV _ _ = []

asString :: Value -> String
asString (String t) = T.unpack t
asString x = show x

Всегда можно что-нибудь смешное написать, типа:

https://gist.github.com/polachok/5154974

В принцпе, конкретно JSON ведь несёт уже в себе аналог Nothing, значит можно по-быстрому нашлёпать что-то похожее.