in your comment, you claim that "you use a grammar if you stack actions and rollback them in reverse" and then proceed by providing an example for an action which is executed and then "rolled back in reverse".
However, I am still missing your argument or explanation for why such roll-back actions are required for the use of grammar. At first glance, I can express events and states-of-affairs grammatically, so I cannot (yet) see why "rolling back actions" should be required for using grammar. I'd be thankful for some clarification.
okay, now I'm puzzled about the "if" in Joachim's first sentence "You use a grammar if you stack actions and rollback them in reverse". I first took it as a semantic claim (i.e. when faced with an action of such-and-such a sort, you use a grammar), but from what I (perhaps too superficially) gather from your recent comments, you are perhaps talking about a technical linguistic claim? Such as "using a grammar IS LINGUISTICALLY LIKE (or EXPLAINED AS?) stacking actions and rolling them back in reverse"?