Someone in my class pointed out something. In §3.3. One-way connections, the following source text is shown:
The Attic is above the Parlour.
The Attic is a dark room above the Parlour.
The following is said about this:
However, there is no one-way connection created in the case of that source text. You can go “down” and “up” just fine. I thought maybe the meaning was with the second sentence taken alone:
The Attic is a dark room above the Parlour.
But you can’t do that because the game won’t compile in the first place.
So I wasn’t sure how to respond to what the manual is talking about here.
You’re correct that two sentences are supposed to be from different source texts–the problem is that the second doesn’t stand alone. The idea (I guess) is that if your source text contains
The Attic is above the Parlour.
then Inform will infer lots of things here–that both the Attic and the Parlour are rooms, that the Parlour is also below the attic. But if your source text contains
The Attic is a dark room above the Parlour.
then Inform won’t infer anything that’s not explicit–not the reverse connection nor even that the Parlour is a room. Which is why it won’t compile. If you try
The Parlour is a room. The Attic is a dark room above the Parlour.
then you get the one-way connection. (BTW “dark” isn’t doing any work here over and above making the room dark–“The Attic is a room above the Parlour” also creates a one-way connection, and also needs the Parlour to be declared.)
This does seem like it could be a bit clearer in the manual.