[racket] date format conversion

prad wrote at 02/12/2011 08:54 PM:
> my son helped me understand what it was doing after we looked check-expect up.  so this runs a function for you and checks to see that the result is really what you say it is going to be!
>
> that's pretty useful, so a second thx!
>   

This use of "check-expect" is what's known as *unit testing*, and is a 
very popular practice for good software development nowadays.

You might enjoy the HTDP textbook ("http://htdp.org/"), which teaches 
using tests like these as part of problem-solving process.

-- 
http://www.neilvandyke.org/