From 83111e51fb7bce002859d8fbe07e15c7d70320a4 Mon Sep 17 00:00:00 2001
From: darkf <lw9k123@gmail.com>
Date: Sun, 20 Oct 2013 17:25:38 -0700
Subject: [PATCH] fix itos to error on non-int inputs

---
 interp.hs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/interp.hs b/interp.hs
index 2fad473..082f307 100644
--- a/interp.hs
+++ b/interp.hs
@@ -66,12 +66,15 @@ _getline UnitV = do
 		{-# NOINLINE unsafe_getline #-}
 		unsafe_getline h = unsafePerformIO $ hGetLine h
 
+_itos (IntV i) = return $ StrV $ show i
+_itos v = error $ "itos: not an int: " ++ show v
+
 initialState = ([stdout, stdin],
 					M.fromList [("id", FnV [(VarP "x", [Var "x"])]),
 						   		("stdout", StreamV 0),
 						   		("putstr", Builtin $ BIF _putstr),
 						   		("putstrln", Builtin $ BIF (\x -> _putstr $ x +$ StrV "\n")),
-						   		("itos", Builtin $ BIF (\(IntV i)  -> return $ StrV $ show i)),
+						   		("itos", Builtin $ BIF _itos),
 						   		("getline", Builtin $ BIF _getline)])
 
 eval :: AST -> InterpState Value