I'm trying to get ls to work in ghci like it does in bash using variadiac arguments in Haskell. I'm stuck at the moment so I thought I'd send this to #haskell-cafe for some help. I'm not quite sure how to proceed. See the main function for what I want the end result to look like. Here is the code: {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE OverloadedStrings #-} -- | An example module. module Example (main) where import qualified Turtle as Turtle import Control.Foldl import Control.Monad.IO.Class lsDirEx :: MonadIO io => io [Turtle.FilePath] lsDirEx = do Turtle.fold (Turtle.ls "/home") list class PrintAllType t where -- use PrintAllType from https://rosettacode.org/wiki/Variadic_function#Haskell process :: [Turtle.FilePath] -> t -- instance MonadIO io => PrintAllType (io [Turtle.FilePath]) where instance PrintAllType (IO [Turtle.FilePath]) where process [] = do -- ls received no args print current directory Turtle.pwd >>= \fp -> Turtle.fold (Turtle.ls fp) list process (filePath:[]) = do -- ls recieved one filePath liftIO $ Turtle.fold (Turtle.ls filePath) list process _ = error "multiple arguments not currently supported" -- instance (Show a, PrintAllType r) => PrintAllType (a -> r) where -- process args = \a -> process (args ++ [fmt a]) -- where fmt thing = _ $ Turtle.format Turtle.w thing ls :: (PrintAllType t) => t ls = process [] -- | An example function. main :: IO () main = do ls -- lists current directory ls ("/home" :: String) -- lists /home directory Thanks, Cody