X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment8.mdwn;h=495ef2f7218b10182b4e955b8d606dae4dea9c70;hp=0b53578a76286e6a5356ac46c1c1f36c2f0ef798;hb=b0ae43400b808fc96a9762d25868d6517e904a48;hpb=6c4fc9cd7b016b9d11522b0f2f48c61f07a8d4c1 diff --git a/assignment8.mdwn b/assignment8.mdwn index 0b53578a..495ef2f7 100644 --- a/assignment8.mdwn +++ b/assignment8.mdwn @@ -1,4 +1,4 @@ -1. Complete the definitions of `move_botleft` and `move_right_or_up` from the same-fringe solution in the [[week11]] notes. Test your attempts against some example trees to see if the resulting `make_fringe_enumerator` and `same_fringe` functions work as expected. +1. Complete the definitions of `move_botleft` and `move_right_or_up` from the same-fringe solution in the [[week11]] notes. **Test your attempts** against some example trees to see if the resulting `make_fringe_enumerator` and `same_fringe` functions work as expected. Show us some of your tests. type 'a tree = Leaf of 'a | Node of ('a tree * 'a tree) @@ -25,6 +25,8 @@ {tree = Root; filler = t} ;; +   + let make_fringe_enumerator (t: 'a tree) = (* create a zipper targetting the root of t *) let zstart = new_zipper t @@ -62,7 +64,7 @@ ;; -2. Here's another implementation of the same-fringe function, in Scheme. It's taken from . It uses thunks to delay the evaluation of code that computes the tail of a list of a tree's fringe. It also involves passing continuations as arguments. Your assignment is to fill in the blanks in the code, and also to supply comments to the code, to explain what every significant piece is doing. +2. Here's another implementation of the same-fringe function, in Scheme. It's taken from . It uses thunks to delay the evaluation of code that computes the tail of a list of a tree's fringe. It also involves passing continuations (`tailk`s) as arguments. Your assignment is to fill in the blanks in the code, **and also to supply comments to the code,** to explain what every significant piece is doing. Don't forget to supply the comments, this is an important part of the assignment. This code uses Scheme's `cond` construct. That works like this;