From df2b273877a4d40baa37bdb45b40169d2d525fd3 Mon Sep 17 00:00:00 2001
From: Adam Chlipala <adam@chlipala.net>
Date: Sun, 9 Aug 2015 11:14:09 -0400
Subject: Fix termination bug in tutorial's isEven/isOdd

---
 doc/intro.ur | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'doc')

diff --git a/doc/intro.ur b/doc/intro.ur
index 770b7b06..b08e2395 100644
--- a/doc/intro.ur
+++ b/doc/intro.ur
@@ -58,12 +58,15 @@ fun fact n = if n = 0 then 1 else n * fact (n - 1)
 fact 5
 (* end *)
 
-fun isEven n = n = 0 || isOdd (n - 1)
-and isOdd n = n = 1 || isEven (n - 1)
+fun isEven n = n = 0 || (n > 1 && isOdd (n - 1))
+and isOdd n = n = 1 || (n > 1 && isEven (n - 1))
 
 (* begin eval *)
 isEven 32
 (* end *)
+(* begin eval *)
+isEven 31
+(* end *)
 
 
 (* Of course we have anonymous functions, too. *)
-- 
cgit v1.2.3