I haven't actually gotten to this exercise yet, but I feel like this is probably related: http://www.ece.uc.edu/~franco/C511/html/Scheme/ycomb.html.  I'm not sure if it will give you some pointers in the right direction.  It basically explains how to "abstract out" the recursive part of a function into a separate function, which is basically what you need.

On Fri, Mar 27, 2009 at 7:21 AM, Michael Mossey <mpm@alumni.caltech.edu> wrote:


Jason White wrote:
Michael Mossey  <mpm@alumni.caltech.edu> wrote:

YAHT has some hard exercises, early on. He introduces continuations in chapter 4, briefly, and then casually asks you to rewrite map and filter  in continuation-passing-style. I was stumped.

So am I.

Do you have any hints for these, without giving the answers away (I know the
answers are in the appendix if I really need them)?

Well, I've got some bad news for you. He doesn't include the answers to the CPS-related questions. Note: YAHT seems to be incomplete in a number of ways, because there are chapter headings that exist only as stubs. However, it's a terrific resource, and my thanks to Hal.

I decided to just move on, and I'll come back to continuations when I find them in another book.

Mike


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