From ddcb9439a958ad7721c9dc20e4267194a385c73c Mon Sep 17 00:00:00 2001
From: Kazu Yamamoto <kazu@iij.ad.jp>
Date: Mon, 24 May 2010 15:38:37 +0900
Subject: [PATCH] simplify eval.

---
 Eval.hs | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/Eval.hs b/Eval.hs
index fda10d1..c35474d 100644
--- a/Eval.hs
+++ b/Eval.hs
@@ -12,22 +12,18 @@ evaluate exp0 = eval exp0 empty
 
 eval :: Exp -> Stack Exp -> Exp
 eval (exp1 :. exp2) stack = eval exp1 $ push exp2 stack
-eval exp1           stack = exec stack exp1
-
-exec :: Stack Exp -> Exp -> Exp
-exec stack0 exp1
-  | isEmpty stack0 = exp1
-exec stack0 exp1@(Var _) = foldl (:.) exp1 $ map evaluate stack0
-exec stack0 S = eval (x :. z :. (y :. z)) stack3
+eval exp1 stack
+  | isEmpty stack = exp1
+eval exp1@(Var _) stack = foldl (:.) exp1 $ map evaluate stack
+eval S stack = eval (x :. z :. (y :. z)) stack3
   where
-    (x,stack1) = pop stack0
+    (x,stack1) = pop stack
     (y,stack2) = pop stack1
     (z,stack3) = pop stack2
-exec stack0 K = eval x stack2
+eval K stack = eval x stack2
   where
-    (x,stack1) = pop stack0
+    (x,stack1) = pop stack
     (_,stack2) = pop stack1
-exec stack0 exp0@(_ :. _) = eval exp0 stack0
 
 ----------------------------------------------------------------