hGetLines.hs

import qualified Data.Text.IO as TIO (hGetLine)
import Data.Text (Text)
import qualified Data.Text as T
import System.IO
import Control.Applicative ((<$>), (<*>), pure)

hGetLines :: Handle -> IO [Text]
hGetLines h = do
  eof <- hIsEOF h
  if eof
    then pure []
    else (:) <$> TIO.hGetLine h <*> hGetLines h

main :: IO ()
main =
  hGetLines stdin >>= mapM_ (putStrLn . show . T.length)