You can take a look at this thread (the link below), while TADS will have a different format, the coding design methods used are universal, so this can give you some ideas (though you'll have to adjust it to TADS' structure of course):
viewtopic.php?f=10&t=4324(this is a locked combat event, aka 'turn combat', you're in one large script block and can't do any other outside-of-combat actions, so if you want a more 'real time' combat system for a text game, where you aren't trapped inside of a large combat script block, then take a look at Pixie's Combat Library)
and also, again, take a look at the library files that I mentioned in my previous post, for more combat coding. If you can't find them, let me know and I'll help you navigate to them or just directly provide you with the links to go to them.