X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment3.mdwn;h=289f818ae60e7652bb41f7adc4d5f2b15d3baf92;hp=df06d526a99c58495f34260629d8977bbc1f9e91;hb=2950fbdc81547d95aa8fda13cc3e042ca264e0e6;hpb=6a60dbeb81ccc4949724a6db13a264a0b322a22d

diff --git a/assignment3.mdwn b/assignment3.mdwn
index df06d526..289f818a 100644
--- a/assignment3.mdwn
+++ b/assignment3.mdwn
@@ -30,7 +30,7 @@ Recall that version 1 style lists are constructed like this (see
 	let iszero = \n. n (\x. false) true in
 	let succ = \n s z. s (n s z) in
 	let mul = \m n s. m (n s) in
-	let pred = \n. iszero n 0 (length (tail (n (\p. make_list junk p) empty))) in
+	let pred = (\shift n. n shift (make\_pair 0 0) get\_snd) (\p. p (\x y. make\_pair (succ x) x)) in
 	let leq = \m n. iszero(n pred m) in
 	let eq = \m n. and (leq m n)(leq n m) in
 	
@@ -107,7 +107,7 @@ be your base case for your recursive functions that operate on these
 trees.
 
 <OL start=6>
-<LI>Write a function that sums the number of leaves in a tree.
+<LI>Write a function that sums the values at the leaves in a tree.
 
 Expected behavior: