Then I do wish you luck, but I don't think you'll ever be able to produce a suitably complete grammar since parts of it will require knowledge of undocumented p

Then I do wish you luck, but I don't think you'll ever be able to produce a suitably complete grammar since parts of it will require knowledge of undocumented proprietary internals of Internet Explorer. Hence we scrape along doing our best with what we can figure out from observing behavior and collecting bug reports. But even with that, is_safe_url() is one of the most prone-to-security-issues functions in Django's codebase.