It is possible to use MPI properties in locks, so you can test for say gender, or species, or your own property you have made, using the door we created for the previous section, we will now prevent people going in and out of the room by depending on the lock status of the door.
@lock #1237=locked:no
This will test the property locked on the current object and see if it is no, if it is no then the door is open, if it is yes, then the door is closed.
Now you have a fully functioning door - impressive!
For testing properties on another item, the property in the lock string has to reference a property on itself, however, the property it is calling may reference anything anywhere. Such as the property locked could look like @set #1237=locked:{if:{eq:{prop:_override,#1234},no},no,yes} this would return no or yes depending on a property on the room.
If you make many exits with the same name, the muck will always go for the unlocked one. If there are multiple unlocked ones of the same name, it will select one at random - it is a good way of making an intriguing puzzle.