iterator? way of generating all possible combinations?

[akameswaran at gmail.com]

This would only work for combinations of identical sets, and also does
not seem to work with generated sets, or iterators.  Forgetting dice
for a moment.  Say I have 3 very long files, and i want to generate the
combinations of lines in the files.  This provides a well known
iterator for the example.

file1 = open('foo.txt')
file2 = open('bar.txt')
file3  = open('baz'.xt')

All examples I have seen and all attempts I have written generally do
something similar - which is they only iterates through the possible
combinations for the last element and do nothing for all other
elements.

I saw an interesting example that generates a nested function for the
given number of sets.  While the example still didn't work with
generators as input, I think a little tweaking would make it work.

This should fulfill my requirements with a rather harsh limit of
python's max nesting depth (20?)