The basic rule is:
- If it’s in a table column named
topic, it’s a topic - If it’s in an
Understand … as …line, it’s a topic - If it’s being used as a noun in a description of an action, it’s a topic
- Otherwise, it’s text
Converting a topic to text is impossible, which is understandable, because a topic is really an arbitrary parsing routine (I think I6 calls these “GPRs”) which can’t necessarily be printed in any meaningful way.
But converting a text variable to a topic is also supposed to be impossible, which doesn’t make sense, since it has a very reasonable interpretation (“match this literal text and nothing else”).
As with many of Inform’s weird quirks, there’s an easy but obscure workaround.
To swap in (t - text):
try typing "[t]".
Since the double-quotes occur in the description of an action, they’re taken as a topic, and a topic can include references to a text in it, meaning “compare the snippet against this text variable”.