automatically grading small programming assignments

[Paul Boddie]

Jeff Rush wrote:
>
> For another solution, I wonder whether you could make use of the new Abstract
> Syntax Tree (AST) in Python 2.5, where you convert the source of an attempt
> into an abstract data structure, anonymize the method/variable/class names and
> compare the tree against a correct solution.  It would let you quickly handle
> those students who solved it in a conformist way, and then you'd need to
> manually review the rest for creatively solving it another way. ;-)

You could attempt that kind of solution using previous versions of
Python (and the compiler module), but as soon as you want to compare
two different ASTs - and I think that unless there's only one obvious
solution, they won't be identical - then you need to descend into a
world of program transformations that Python doesn't encourage. It's
probably no coincidence that the functional programming people were
probably the only people trying this kind of automatic grading back
when I was a student.

Paul