"Rooms Within Rooms" by John Timmons

The story headline is "Using the Container Object to Create the Illusion of a Room Within a Room". The story description is "This is a simple example of how one might create an enterable container to serve as a tent that the player can enter and exit plus few other container 'tricks'."

Release along with the source text, a website, and an interpreter.

[Here is our simple starting room.]
Back Yard is a room. "The yard has a beautifully manicured lawn."

[Here is the tent that the player can enter and exit but not be able to take.]
The tent is an enterable container in the back yard. It is fixed in place. The description is "A bivouac style tent that probably could hold one person."

[The following after rule prevents any contents of the tent from being listed in the room description.]
After printing the name of the tent:
	omit contents in listing.
	
[The following instead rule prevents the contents of the tent from being displayed when the player examines it. The player will have to either "search the tent" or "look in tent" to see the contents before actually entering it.]
Instead of examining the tent:
	say "[description of the tent][line break]".
	
[Here is something to have inside the tent.]
The thermos is in the tent.


[By default, a player can simply type "enter" or "get in" to go inside an enterable container. Should there be more than one enterable container present, then the player will have to be more specific: "enter tent", "get in tent", or "go in tent".

Getting out of an enterable container can pose problems however. By default, all the player needs to do to get out of an enterable container is to simply type "exit", "leave" or "get out".  A player may not know this and more probably type "exit the tent", "leave tent", or "get out of the tent" only to discover that Inform doesn't quite understand what the player is trying to do.  We can use the 'understand' command to teach Inform how to treat such input from the player and hopefully prevent some frustration.]
Understand "exit tent", "exit the tent", "exit the booth", "leave tent", "leave the tent", "get out of tent", or "get out of the tent" as exiting.

[Remember: if you have more than one enterable container in your game, this understand command will affect the behavior of those as well. There are other cleaner and more efficient ways but this method should work fine in most cases.]