Jay Ashworth wrote:
...there's a project underway to formalize the very wikitext grammar with which you're compatible. I know someone posted a pointer last week, but I don't have it handy; I suspect they'll chime in.
("ding, dong. ding, dong.")
There's http://www.mediawiki.org/wiki/Markup_spec which is a prose description, with several more formal BNF descriptions hanging off of it as subpages (see http://www.mediawiki.org/ wiki/Special:Search/Markup_spec/BNF/ for a list).