[racket] a small programming exercise

Speaking as a user of TR, I would really far prefer that the
compilation time shrank before there were more optimizations.

The *perceived* time between hitting F5 and getting a prompt is huge.
In my class, when I run a typed program, there are nervous titters and
jokes about how long it's going to take.

Obviously I, and the students making the jokes, like TR overall --
some of my students are even doing all their coursework in TR.  But
I'm sure you've seen the studies on how people can perceive even small
delays (Google found that a half-second delay led to a 20% loss in
user traffic).

Shriram