X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=assignment_3_evaluator.mdwn;h=c4032ee37c7f1ec456a09f7ed5a88093f932bd64;hb=94f47d126b9513c2a198eba685d44030bc31ac1d;hp=c910064a790698d67cc27a0dd807b3acca70f3a3;hpb=2950fbdc81547d95aa8fda13cc3e042ca264e0e6;p=lambda.git

diff --git a/assignment_3_evaluator.mdwn b/assignment_3_evaluator.mdwn
index c910064a..c4032ee3 100644
--- a/assignment_3_evaluator.mdwn
+++ b/assignment_3_evaluator.mdwn
@@ -5,6 +5,8 @@ Here are the definitions pre-loaded for working on assignment 3:
 let true = \x y. x in
 let false = \x y. y in
 let and = \l r. l (r true false) false in
+let or = \l r. l true r in
+;
 let make\_pair = \f s g. g f s in
 let get\_fst = true in
 let get\_snd = false in
@@ -40,7 +42,29 @@ let makeList = make\_list in
 let isZero = iszero in
 let mult = mul in
 ;
-length (tail mylist)
+let t1 = (make\_list 1 empty) in
+let t2 = (make\_list 2 empty) in
+let t3 = (make\_list 3 empty) in
+let t12 = (make\_list t1 (make\_list t2 empty)) in
+let t23 = (make\_list t2 (make\_list t3 empty)) in
+let ta = (make\_list t1 t23) in
+let tb = (make\_list t12 (make\_list t3 empty)) in
+let tc = (make\_list t1 (make\_list t23 empty)) in
+;
+;sum-leaves t1 ; ~~> 1
+;sum-leaves t2 ; ~~> 2
+;sum-leaves t3 ; ~~> 3
+;sum-leaves t12 ; ~~> 3
+;sum-leaves t23 ; ~~> 5
+;sum-leaves ta ; ~~> 6
+;sum-leaves tb ; ~~> 6
+;sum-leaves tc ; ~~> 6 
+;
+let add = \l r. l succ r in
+let fold = Y (\f g l z. isempty l z (g (head l)(f g (tail l) z))) in
+;
+; hint: 
+fold add mylist 0
 </textarea>
 
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