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§9.2. Bags, Bottles, Boxes and Safes

The kind "container" allows one thing to contain others. Things are sometimes containers automatically, sometimes by instruction:

The match is in the matchbox. The bucket is a container.

The matchbox, like the bucket, is a container. Containers come in all sizes and have a variety of behaviours, mainly controlled by the properties we give them: they can be "open" or "closed", "opaque" or "transparent" (when closed), "openable" or not, "lockable" or not, "enterable" or not. The basic ideas of containment are to do with carrying and sometimes hiding the contents, and Inform makes this easy. Allowing for locking and unlocking is again straightforward:

The strongbox is a locked container. The little steel key unlocks the strongbox.

Two built-in extensions enhance and modify the behavior of locks and keys: Locksmith automates a number of steps, automatically unlocking doors when trying to open them (for instance). Skeleton Keys allows us to define multiple keys that unlock the same object, rather than being restricted to one matching key per item.

For a container with a combination lock, rather than a key, see Safety; for a more sophisticated safe requiring digits dialed over multiple turns, see Eyes, Fingers, Toes.

Trachypachidae Maturin 1803 provides a bottle that is stoppered with a cork: when it is closed, the cork is part of the bottle, but otherwise the cork becomes a separate object we can carry around.

The normal assumption is that there is no problem with any two portable items being carried together, but in reality they may affect each other. (For effects like magnetism, or getting each other wet, or setting each other on fire, see the Physics chapter.) Here is a cat which, if boxed up with one or more items of food, will eat something each turn until all is gone:

The player carries a wicker basket and a scarlet fish. The cat is an animal in the wicker basket. The fish is edible.

Every turn when the cat is in a container (called the bag) and something edible (called the foodstuff) is in the bag:
    remove the foodstuff from play;
    say "With mingled sounds of mewing and chomping, the cat nibbles up [the foodstuff]."

The examples below provide subtler effects, adapting text to the current situation. In Cinco, the container's name changes depending on what it contains: putting beef in a taco allows the player to call it a SHREDDED BEEF TACO. In Unpeeled and Shipping Trunk, the description of something inside a container changes according to other things are alongside it. This is taken further in Hudsucker Industries, which describes the contents of a container as a group.

Finally, any action that destroys a container has to consider what to do with the things inside. Fallout Enclosure demonstrates a zapping action that destroys cash registers and shelves but leaves their contents tidily behind.

* See Liquids for a SHAKE command that makes containers rattle when there are contents

* See Glass and Other Damage-Prone Substances for opening containers by cutting into them

* See Fire for fire damage that spreads between containers and their contents, leaving fireproof objects intact

* See Volume, Height, Weight for containers breaking under the weight of their contents

* See Heat for keeping things warm in insulated containers

* See Furniture for chests with lids that can support other objects

* See Modifying Existing Commands for ways to allow the player to unlock with a key he isn't currently holding

arrow-up.png Start of Chapter 9: Props: Food, Clothing, Money, Toys, Books, Electronics
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A safe whose dial can be turned with SPIN SAFE TO 1131, and which will open only with the correct combination.

A taco shell that can be referred to (when it contains things) in terms of its contents.

*ExampleShipping Trunk
A box of baking soda whose name changes to "completely ineffective baking soda" when it is in a container with something that smells funny.

Calling an onion "a single yellow onion" when (and only when) it is being listed as the sole content of a room or container.

*ExampleEyes, Fingers, Toes
A safe with a multi-number combination, meant to be dialed over multiple turns, is implemented using a log of the last three numbers dialed. The log can then be compared to the safe's correct combination.

**ExampleTrachypachidae Maturin 1803
Bottles with removable stoppers: when the stopper is in the bottle, the bottle is functionally closed, but the stopper can also be removed and used elsewhere. Descriptions of the bottle reflect its state intelligently.

**ExampleHudsucker Industries
Letters which are described differently as a group, depending on whether the player has read none, some, or all of them, and on whether they are alike or unlike.

***ExampleFallout Enclosure
Adding an enclosure kind that includes both containers and supporters in order to simplify text that would apply to both.