[plt-scheme] List loop timing

Carl Eastlund wrote:

> Personally, I learned how to write linear-time reverse in a lesson on
> accumulators, in which tail recursion wasn't once mentioned (mostly
> because I was programming in C).  You're used to seeing it tied up
> with tail recursion, but the tie is not inherent.

Fair enough. I learned it that way, too, in Pascal. I have the fortune 
of being able to teach it in the other direction (Scheme->C) this term. 
I wish I'd had the fortune to learn it this way. --PR