It looks like run-teaching-program hasn't been touched in quite a while.
To begin with, the "rewrite-module" function used to add code to print
out values of non-define exprs, but this is no longer necessary. In fact,
the only thing that it does now is to discard "provide" statements, and
even this may be unnecessary. I rewrote big chunks of this (short) file
to introduce defines, eliminate unnecessary functions, and add stepper-
skip-completely annotations to the requires associated with teachpacks.
Also, it appears that the 'rep' argument to expand-teaching-program
was entirely superfluous; I removed it from the argument list, and also
from the three places in the main tree (deinprogramm, lang, and the stepper)
that call this function.
Let me know of any problems seen with teachpack requires....
parameter. Specifically, it is expected to be a namespace that has the GUI
bindings available. Unfortunately, during the dynamic extent of the
uncaught-exception-handler when a syntax error is raised, this may not be
the case because you get a phase 1 namespace, not a phase 0 one.
So, move the call to display-results to the code that runs the student language
programs and out of the uncaught exception handler.
