I've been playing with this, and the other downside is that it's slow. Things are noticeably slower to load (not to run), as the ssyntax check is (a) more complex, and (b) written in Arc, not mzscheme. Other than those two things, though, it's absolutely great.
Hmm. After looking at that, as far as I can tell it can only match a word which ends in one of the strings in its dictionary. Using it to parse out middle bits would be tricky--you could try saving the string at each accept state, or something like that.
