[plt-scheme] automarking again

Eli Barzilay wrote:

> Did you consider using the handin server & client?  Besides the
> submission thing, it can test and reject if tests fail, or show
> warnings, or record test results.

It's still overkill for me. We have a working electronic submission 
system which my academic support staff understand. To use the handin 
server and client, I'd have to get students to install the plugin, run 
the PLT Web server, and most importantly, understand how it all works so 
I can configure it, adapt it to our peculiar local customs, and fix 
anything that goes wrong. Right now I have ways of getting student code 
into individual directories, one for each student, containing assignment 
directories and individual questions within them. I just need to run 
their code, with my tests, in the appropriate language level, and record 
the output.

I've been looking at your utils.ss but I can only dimly understand bits 
of what it is doing. Threads seem to be involved, and namespaces, both 
of which I know very little about.

I think I will try to wrap student code in a module declaration with 
requires to get me access to I/O. I thought I could build a sequence of 
arguments to mzscheme but it appears not. --PR