X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=exercises%2Fassignment5.mdwn;h=f4955d9db34f525c0178c3e320769bee5d9a474e;hp=00ede5aaf1ef0ff93018070b18ef3ddc606ba69f;hb=d7b2ba7d870cccd91313e5d32a6c195ee5140dcd;hpb=6922b3d0f2e4fc3a60bc2a388bac5586156beb9f diff --git a/exercises/assignment5.mdwn b/exercises/assignment5.mdwn index 00ede5aa..f4955d9d 100644 --- a/exercises/assignment5.mdwn +++ b/exercises/assignment5.mdwn @@ -116,7 +116,7 @@ Choose one of these languages and write the following functions. 6. How would you use the function defined in problem 4 to enumerate a tree's fringe? (Don't worry about whether it comes out left-to-right or right-to-left.) -7. Write a recursive function to make a copy of a `color_tree` with the same structure and inner branch colors, but where the leftmost leaf is now labeled `0`, the second-leftmost leaf is now labeled `1`, and so on. (Here's a [[hint|assignment5 hint3]], if you need one.) +7. Write a recursive function to make a copy of a `color_tree` with the same structure and inner branch colors, but where the leftmost leaf is now labeled `0`, the second-leftmost leaf is now labeled `1`, and so on. (Here's a [[hint|assignment5 hint4]], if you need one.) 8. (More challenging.) Write a recursive function that makes a copy of a `color_tree` with the same structure and inner branch colors, but replaces each leaf label with the `int` that reports how many of that leaf's ancestors are labeled `Red`. For example, if we give your function a tree: @@ -384,7 +384,7 @@ Yet we haven't given ourselves the capacity to talk about `list [S]` and so on a = λf:T -> S. λxs:list. xs [T] [list [S]] (λx:T. λys:list [S]. cons [S] (f x) ys) (nil [S]) --> -*Update: Never mind, don't bother with the next three questions. They proved to be more difficult to implement in OCaml than we expected. Here is [[some explanation|assignment5 hint3]].* +*Update: Never mind, don't bother with the next three questions. They proved to be more difficult to implement in OCaml than we expected. Here is [[some explanation|assignment5 hint4]].* 19. Convert this list encoding and the `map` function to OCaml or Haskell. Again, call the type `sysf_list`, and the functions `sysf_nil`, `sysf_cons`, and `sysf_map`, to avoid collision with the names for native lists and functions in these languages. (In OCaml and Haskell you *can* say `('t) sysf_list` or `Sysf_list t`.)