From f138c7475b8d2d12d4e3e633522cc2a72078d718 Mon Sep 17 00:00:00 2001
From: darkf <lw9k123@gmail.com>
Date: Sun, 20 Oct 2013 16:32:23 -0700
Subject: [PATCH] add helper bind function

---
 interp.hs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/interp.hs b/interp.hs
index 97490ce..1919daf 100644
--- a/interp.hs
+++ b/interp.hs
@@ -27,6 +27,9 @@ type InterpState = State ([Handle], Env) -- interpreter state (open handles, glo
 lookup :: Env -> String -> Maybe Value
 lookup env name = M.lookup name env
 
+bind :: Env -> String -> Value -> Env
+bind env name value = M.insert name value env
+
 (IntV l) +$ (IntV r) = IntV (l + r)
 (StrV l) +$ (StrV r) = StrV (l ++ r)
 l +$ r = error $ "cannot + " ++ show l ++ " and " ++ show r
@@ -81,8 +84,8 @@ eval (Var var) = get >>= \(_,env) ->
 
 eval (Def name v') = do
 	v <- eval v'
-	(s,m) <- get
-	put (s, M.insert name v m)
+	(s,env) <- get
+	put (s, bind env name v)
 	return v
 
 eval (Lambda pats) =