version 2/110308 by Mike Ciul
Section: The Noticing Absence Activity
The heart of Lost Items is the "noticing absence" activity. When the parser is about to give the error "you can't see any such thing," the "check for lost items" rule intercepts it. If the player did mention a lost item in his or her command, the Noticing Absence activity is performed with the mentioned item.
If the player mentions more than one lost item, or uses a phrase that matches more than one lost item, only the first item checked will be used. It is assumed that there will only be a small number of losable items, so there shouldn't be many conflicts, but it is important to be aware of this possibility.
The "default notice absence rule" for noticing absence normally handles the Noticing Absence activity. It tells the player:
(The missing item) doesn't seem to be here anymore.
To customize the message, we may replace the default notice absence rule, or add additional rules for different items and situations.