Regions

A region groups rooms and owns behavior for all of them. A room joins a region with an in the <region> line in its own block, and a region can declare a set of identical rooms itself with a rooms group; a room is in at most one region, and regions do not nest. An on every turn clause is a region daemon firing only while the player is in a member room, and after the player entering / after the player leaving bind to boundary crossings in either direction. leaving exists only on region blocks.

create the Grounds
  a region
  landing the Drive

  on every turn while one chance in 6
    phrase night-wind
  end on

  after the player entering
    phrase cold-returns
  end after

  after the player leaving
    phrase out-of-the-wind
  end after

create the Drive
  a room
  in the Grounds

  A gravel drive.

create the Hall
  a room
  in the Grounds

  A cold hall.

Identical rooms, such as the rooms of a maze, are declared once with their count: rooms Maze 1 to 12 inside the region creates the Maze 1 to the Maze 12, each a member, each taking the group's heading and description as its own. A room that needs anything of its own, a clause or different text, is written as its own block with an in line instead.

create the Maze
  a region

  rooms Maze 1 to 12
    room name:
      Maze

    You are in a maze of twisty little passages, all alike.

A region becomes a place once it says where things land. landing the Drive names the room that move … to the Grounds puts an entity in, and it is what the Grounds's location means. A list must say how to choose — landing, randomly: the Drive, the Hall — with cycling and stopping as the other two strategy words, drawn on the region's own seeded stream. One landing line per region, every room in it one of the region's members, and set the Grounds's landing to the Hall replaces the whole list with that one room. A region with no landing cannot be moved to, but is in the Grounds is a membership test either way: true in any member room, with no landing line needed.