1 files changed, 12 insertions, 3 deletions

diff --git a/examples/Client.hs b/examples/Client.hs
index abf62657..26711676 100644
--- a/examples/Client.hs
+++ b/examples/Client.hs
@@ -1,9 +1,11 @@
 {-# LANGUAGE RankNTypes                #-}
+{-# LANGUAGE CPP                       #-}
 {-# LANGUAGE ExistentialQuantification #-}
 {-# LANGUAGE RecordWildCards           #-}
 module Main (main) where
 import Control.Concurrent
 import Control.Monad.Trans
+import Data.Maybe
 import Options.Applicative
 import System.Environment
 import System.Exit
@@ -12,6 +14,13 @@ import Text.Read
 
 import Network.BitTorrent
 
+#if MIN_VERSION_optparse_applicative(0,13,0)
+-- maybeReader imported from Options.Applicative.Builder
+#elif MIN_VERSION_optparse_applicative(0,11,0)
+maybeReader f = eitherReader (maybe (Left ":(") Right . f)
+#else
+maybeReader f = f
+#endif
 
 {-----------------------------------------------------------------------
 --  Command line arguments
@@ -29,17 +38,17 @@ argsParser = Args <$> (TorrentBox <$> infohashP <|> TorrentBox <$> torrentP)
                   <*> destDirP
   where
     infohashP :: Parser InfoHash
-    infohashP = argument readMaybe
+    infohashP = argument (maybeReader readMaybe)
                 (metavar "SHA1"     <> help "infohash of torrent file")
 
     torrentP :: Parser FilePath
-    torrentP  = argument Just
+    torrentP  = argument (maybeReader Just)
                 ( metavar "FILE"
                <> help    "A .torrent file"
                 )
 
     destDirP :: Parser FilePath
-    destDirP  = argument Just
+    destDirP  = argument (maybeReader Just)
                 ( metavar "DIR"
                <> help    "Directory to put content"
                 )