| Chapter 3: Things |

| 3.13. Locks and keys

It seems unwise for a door in Notting Hill to be unlocked, so:

> The blue door is lockable and locked. The matching key of the blue door is the brass Yale key.

Since the second sentence here is a little clumsy, we can equivalently say

> The brass Yale key unlocks the blue door.

Yet a third way to say this is:

> The blue door has matching key the brass Yale key.

This introduces three new properties: a door can be locked or unlocked; lockable or not lockable; and it can have a matching key, which must be another thing. The same thing can be the matching key of many different locks: and note that a door can be locked and even lockable without having a matching key at all, in which case the player trying to open it will be permanently out of luck. Doors are ordinarily unlocked, not lockable, and without a matching key.

Containers can also have locks, in exactly the same way, and are allowed to have the same properties. On the other hand supporters never have locks: it makes no sense to be able to lock a tabletop, for instance, and Inform will not allow any discussion of the matching key of a supporter, or of a supporter being locked or unlocked.

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| Example Disappointment Bay 6 Disappointment Bay: locking up the charter boat's fishing rods.

It stands to reason that the captain wouldn't let just anyone meddle with his fishing equipment; maybe he keeps that case locked. We could replace the case description with this one, instead: The Cabin contains a glass case. In the glass case is a collection of fishing rods. The case is closed, transparent, openable, lockable, and locked. The case is scenery. The small silver key unlocks the case. Now there's a silver key that will unlock it -- though since we haven't said where the key is, the player will never be able to find it in the game. (If we look at the World index, we find "small silver key" right at the bottom, not inside any of the rooms. That is as good as not existing at all -- though we usually use the term "out of play" -- but as we will later see, it is possible to have things initially out of play but brought into existence later on.)

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| Example Neighborhood Watch A locked door that can be locked or unlocked without a key from one side, but not from the other.

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