{- ########################################################################

   module ReadLine calls the readline function in the GNU readline
   library.  (This can also be done in GHC but (a) it's not in
   GHC 4.02; (b) it's not in Hugs; (c) it's a good exercise for Green Card.

   ####################################################################### -}

module ReadLine(readLine) where
import StdDIS
import Addr


%#include "readline.h"
%#include "stdlib.h"

%fun readline :: String -> IO Addr
-- readline routine itself

readLine :: String -> IO String
readLine prompt =
   do
      addr <- readline prompt
      if addr == nullAddr
         then
            ioError(userError "Cannot read from terminal")
         else
            return ()
      res <- unmarshall_string_ addr
      free addr
      return res