From 2950fbdc81547d95aa8fda13cc3e042ca264e0e6 Mon Sep 17 00:00:00 2001 From: Jim Pryor Date: Sun, 3 Oct 2010 19:02:10 -0400 Subject: [PATCH 1/1] fixed assignment3 pred Signed-off-by: Jim Pryor --- assignment3.mdwn | 2 +- assignment_3_evaluator.mdwn | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/assignment3.mdwn b/assignment3.mdwn index f84d07f9..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 diff --git a/assignment_3_evaluator.mdwn b/assignment_3_evaluator.mdwn index 496003d0..c910064a 100644 --- a/assignment_3_evaluator.mdwn +++ b/assignment_3_evaluator.mdwn @@ -21,7 +21,7 @@ let mylist = make\_list 1 (make\_list 2 (make\_list 3 empty)) in 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 ; -- 2.11.0