Those ZIL grammar flags

A couple of months ago I referred to a quote from Infocom's internal ZIL manual: The other four tokens—ON-GROUND, IN-ROOM, HELD, and CARRIED—are incredibly confusing, and no one really understands them except Stu, so he should probably write this bit. -- Learning ZIL, chapter 9.6 That post was about the social context in which Steve Meretzky wrote those words. So I didn't get into what the ZIL tokens meant. But this week the question came up on the Visible Zorker Discord. Let's get technical! (This post is also available on my Patreon.) What kind of tokens are we talking about? The manual again: There are several tokens which can appear in parentheses within a syntax definition: HAVE, TAKE, MANY, EVERYWHERE, ADJACENT, HELD, CARRIED, ON-GROUND, and IN-ROOM. This parenthetical list appears after either or both OBJECTs: <SYNTAX GIVE OBJECT (HAVE) TO OBJECT (ON-GROUND IN-ROOM) = V-GIVE> (I've spaced out the <SYNTAX> line for clarity.) This example defines a grammar line: GIVE ___ TO ___.…