gistfile1.hs

module Main (main) where

import System.Environment (getArgs)
import System.Console.GetOpt

data SearchOptions
    = Query String | Rpp Int | Lang String | OutputFile String
      deriving (Show)

options :: [OptDescr SearchOptions]
options = [
 Option ['q'] ["query"]            (ReqArg Query "QUERY")       "query string",
 Option ['r'] ["rpp"]              (ReqArg (Rpp . read) "RPP")  "RPP",
 Option ['l'] ["lang", "language"] (ReqArg Lang "LANG")         "language",
 Option ['o'] []                   (ReqArg OutputFile "OUTPUT") "output file"
 ]

main :: IO ()
main = do
  args <- getArgs
  case getOpt Permute options args of
    (o, n, [])     -> print (o, n)
    (_, _, errors) -> ioError (userError (concat errors ++ usageInfo "help" options) )