Cabal-ize and readline-ize

Setup.hs

@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain

hsnock.cabal

@@ -0,0 +1,12 @@
+name:                hsnock
+version:             0.1.0.0
+synopsis:            Nock 5K interpreter
+author:              Steven Dee
+maintainer:          mrdomino@gmail.com
+category:            Language
+build-type:          Simple
+cabal-version:       >=1.8
+
+executable hsnock
+  main-is:             nock.hs
+  build-depends:       base ==4.5.*, parsec ==3.1.*, readline

nock.hs

@@ -1,28 +1,23 @@
 #!/usr/bin/env runhaskell
 {-# LANGUAGE ScopedTypeVariables #-}
+import Prelude hiding (catch)
 
 import Nock5K.Parse
 import Nock5K.Spec
 import Control.Exception
-import System.Exit
-import System.IO
-import System.IO.Error (isEOFError)
+import System.Console.Readline
 import Text.ParserCombinators.Parsec (parse)
 
-rep = srpa >>= print . nock
+repl = do ln <- readline "nock "
+          case ln of
+            Nothing     -> return ()
+            Just "exit" -> return ()
+            Just s -> do addHistory s
+                         case parse noun "" s of
+                           Left e -> print e
+                           Right n -> ep n
+                         repl
   where
-    srpa = s >> r >>= pa
-    s = putStr "nock " >> hFlush stdout
-    r = getLine
-    pa l = case parse noun "" l of
-      Left e -> hPrint stderr e >> srpa
-      Right n -> return n
+    ep n = (print . nock) n `catch` (\(e :: SomeException) -> print e)
 
-repl = rep `catches` hs >> repl
-  where
-    hs = [ Handler (\(e :: IOException) ->
-             if isEOFError e then exitSuccess else hPrint stderr e)
-         , Handler (\(e :: SomeException) -> hPrint stderr e) ]
-
-desc = "Nock 5K. ^D to exit."
-main = putStrLn desc >> repl
+main = repl