We can now define the second room in the game. Since this will be an interior room (albeit inside a cave rather than a building) we'll make it of the Room class:
entranceCave : Room 'Entrance Cave' 'the entrance cave'
"Compared with the narrow tunnel leading out to the north, this
rough-walled cave seems positively spacious. A red sign fixed to
one wall suggests that the narrow tunnel is the only way back out to
the valley, while a blue sign next to it welcomes you to the cave.
Directly under the signs a narrow ledge has been carved into the
wall. There appear to be no other caves at this level, but a sturdy
steel ladder leads down through a large round hole in the floor. "
north = entranceTunnel
Note that the cave's north property points to the previously defined RoomConnector, and that we use the asExit macro to allow OUT as a synonym for NORTH.
Once again, note the use of the Room template to define the common properties of this Room. The first single-quoted string, 'Entrance Cave' is the name of the Room. The second 'the entrance cave' (which is optional - we could just leave it out) is its destName (the name that will appear in exit listings). The double quoted string that follows, "Compared with the narrow... ", is the room description.
Although this is an underground cave, we assume it will be permanently lit by some means or other. In more complex situations you might want to override the brightness property to vary according to circumstance (as is exemplified in the definition of the secretPassage, which comes later).
At this point it should be possible to compile and test the game once more.