1 files changed, 30 insertions, 0 deletions
diff --git a/src/unlambda.hs b/src/unlambda.hs
new file mode 100644
index 0000000..b06b42f
--- /dev/null
+++ b/src/unlambda.hs
@@ -0,0 +1,30 @@
+
+import System.Environment( getArgs )
+import Control.Exception( ErrorCall(..), Handler(..), catches )
+import Unlambda.Parser
+import Unlambda.Interpreter
+
+
+
+
+usageString :: String
+usageString = "Usage: unlambda <program file>"
+
+
+
+program :: IO ()
+program = do
+    args <- getArgs
+    fileContents <- if (length args /= 1)
+                    then error usageString
+                    else readFile (head args)
+
+    case (parseUnlambda fileContents) of
+        Left x -> putStrLn (show x)
+        Right x -> unlambda x >>= putStrLn . show
+
+
+
+main = catches program
+               [ Handler ((\e -> putStrLn . show $ e) :: ErrorCall -> IO ()) ]
+