Expanses

An expanse is a bounded space with coordinates: a sea, an asteroid belt, a desert — anywhere a vessel is between places rather than in one. It is the use expanses extension; write the line in the story header, and the expanse kind, movement: open and the coordinates command set become available. An expanse lowers to a room, so the room heading, look and scope read it as they read any room, and its own prose describes it.

story
  title: The Belt
  authors:
    ref
  id: belt
  story-version: 0.0.1
  use expanses

The expanse writes size: <w> by <h> and a landmarks block whose rows place rooms in it at coordinates. A landmark is an ordinary room; a vehicle that reaches its cell arrives in it. seen from afar: on a room or a vehicle is the line a looker sees when it is in sight but not here.

create the Belt
  an expanse
  size: 20 by 8
  drift: 1 unit every 50 turns
  north is blocked: ice-fields
  aka belt, void

  Black, and the slow tumble of rock against it.

  landmarks
    the Mining Platform: 3, 3
    the Derelict: 14, 6
  end landmarks

define phrase ice-fields
  Ice closes the way north; the skiff will not answer that heading.
end phrase

create the Mining Platform
  a room
  seen from afar: a cluster of lights on a lopsided rock
  sight: 4

  A platform bolted to a rock, its lights the only warm thing for miles.

create the Derelict
  a room
  seen from afar: a long dead hull, turning slowly end over end

  The inside of a hull that has not held air in a hundred years.

An open vehicle

movement: open is a vehicle with a position in an expanse rather than a room. It starts in <expanse> at <x>, <y> or in a landmark, and writes three lines the type needs: pace: (turns per step), stride: (units per step) and sight: (how far one sees from it, in units). Speed is entirely the author's: a long voyage is long by the numbers written here, and no command changes them.

create the skiff
  a vehicle
  in the Belt at 3, 3
  movement: open
  carries: in
  drive: player
  commands: compass, coordinates
  pace: 1 turn
  stride: 1 unit
  sight: 6
  seen from afar: a glint of hull against the dark
  aka craft

  A skiff: one seat, one console, a hull you can see through.

create the telescope
  a thing
  in the skiff
  sight: 12
  aka scope

  A brass telescope, older than the skiff.

Two command sets drive it. compass is the base set — steer north, go north from inside, heave to — and under use expanses a heading is held across the open until something stops it. coordinates adds set course for <x>, <y> and set course for <landmark>. Under drive: control the story writes start <vehicle> heading <direction> or send <vehicle> to <landmark or coordinates> instead.

> set course for the Derelict
You set course for the Derelict.

> wait
Time passes...

> wait
Time passes...

> wait
Time passes...

> wait
Time passes...

> wait
Time passes...

The lookout cries: the Derelict is in sight.

Sight

Whoever looks sees in bands, and out of sight is out of scope. From the skiff, anything within its sight: is reported — close by, in the distance, or on the horizon, with its direction — and a thing carrying sight: of its own is an instrument: look through the telescope looks once with its reach instead.

> look
Mining Platform
A platform bolted to a rock, its lights the only warm thing for miles.

You can see a skiff here.

In the skiff you see a telescope and an Alex.

The cask, in the distance, to the east.

> look through telescope
You look through the telescope.

The cask, on the horizon, to the west.

The Mining Platform, on the horizon, to the west.

The same bands are conditions — <thing> is in sight, is close by, is in the distance, is on the horizon — and when <thing> comes into sight is an anchor a sequence or an after clause can wait on, which is how the lookout above cries out:

define phrase land-ho
  The lookout cries: the Derelict is in sight.
end phrase

define sequence landfall
  when the Derelict comes into sight
    phrase land-ho
end sequence

<vehicle> is within <n> of <landmark> reads distance; <vehicle> is in <expanse>, is at <landmark>, is heading <direction> and is under way read where it is. An expanse's description varies by position with the ordinary per-entity override, phrase description while <condition>:, gated on any of these. A voyage of a hundred turns is as eventful as the author makes it.

Edges

Each side of an expanse may carry a blocked-exit line, north is blocked: <phrase>, for north, south, east and west. A step that would pass an edge ends at it, stops the vehicle, and says the phrase once; a vehicle never crosses one. An edge with no line of its own gets the stock line.

> steer north
You steer the skiff north.

> wait
Time passes...

Ice closes the way north; the skiff will not answer that heading.

Floating things

A thing marked floats may sit in the expanse with coordinates of its own, and drifts: the expanse's drift: 1 unit every <n> turns moves every floating thing one unit in a random direction, on the story's seed. When the vehicle is alongside — in the same cell — retrieve the cask brings it aboard; a floating thing that drifts into a landmark's cell washes up in that room.

create the cask
  a thing, floats
  in the Belt at 5, 3
  aka barrel

  A tarred cask, riding low.

Anything else dropped or thrown overboard is lost: it goes offstage and the stock line says it drifts away, which a thing's own phrase lost-overboard can replace. The player may leave the vehicle in the open; they stay in its cell, can go nowhere on their own, and enter or board any open vehicle alongside.

Wind, bearings in degrees and sails are a further extension on top of this one: Sailing.