X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment_3_evaluator.mdwn;h=c4032ee37c7f1ec456a09f7ed5a88093f932bd64;hp=28693f436d9360d5603354a48ecf498e32633e8f;hb=d50ce29231fc7454463b0a1b7b898022db6b67d1;hpb=4cea4f69242f3a229292186c8fa652942f31f8b8 diff --git a/assignment_3_evaluator.mdwn b/assignment_3_evaluator.mdwn index 28693f43..c4032ee3 100644 --- a/assignment_3_evaluator.mdwn +++ b/assignment_3_evaluator.mdwn @@ -42,24 +42,29 @@ let makeList = make\_list in let isZero = iszero in let mult = mul in ; -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 t3) in -let tc = (make_list t1 (make_list t23 empty)) in +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 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 ; -length (tail mylist) +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