[plt-scheme] using plt-match.ss in teaching languages

Matthias Felleisen wrote:

> it works in all levels in my svn (version 3.99.0.23-svn1may2008 [3m].) I 
> think you're seeing a bug in match that was recently fixed.

Thanks, yes. Goodbye to 3.99.0.18!

But now it says, after printing the right results:

This program should be tested.

Which, after a bit of digging, I now understand as well.

> I strongly discourage pattern matching in the first semester. Been 
> there, done that, failed with it. -- Matthias

That was milder than I expected!

This is for the advanced course -- top 5-10% of incoming students, 
admission by instructor consent only. And I'm not leaning heavily on it. 
--PR