I'd suggest looking at the t/op/re_tests file from Perl 5. It's based on the test suite that originally came with Henry Spencer's regular expression package. It would, of course, need to be translated and extended, but it contains a lot of torturous tests for the standard rx behavior. And it's all just a table of tests and results, so no Perl code at all.
Oh, and for your reference purposes an update of S5 is in the works. More news on that later today. Larry
