use: platform extensions

A use <extension> line in the story header admits one trusted platform extension's vocabulary (combat, scoring, hunger, chapters, expanses, sailing) and triggers its runtime registration; a use-only story stays pure IR. (NPC vocabulary and state machines are core and always on: define machine … end machine needs no use line, and writing use state-machines is a compile error that says so.) Each extension brings manifest-typed trait adjectives (combatant with health 20 and skill 40, the NPC library's guard/patrol/…), use scoring the ranks and award (Scoring), use hunger the depleting meter (Hunger), and use chapters the define chapters … end chapters block with its during, before, and after conditions (Chapters), use expanses the expanse kind — a bounded space with coordinates — and movement: open for a vehicle that crosses it by heading or by course, with sight in distance bands, edges, floating things that drift, and the coordinates command set (ADR-376), and use sailing, which builds on use expanses and must be written beside it, bearings in degrees, the naval command set, the expanse's wind:, the vehicle's sailing block of paces by the angle off the wind, and sails (ADR-375). Alongside these, the media surface (define sound/image/music … from "<file>", play sound, play ambient, show image, define channel data projections, and the client has <capability> condition) lets a story drive the browser client with no story TypeScript; text-only clients degrade cleanly. The full catalog of forms lives in the grammar reference.

story
  title: Extensions
  authors:
    ref
  id: ext-ref
  story-version: 0.0.1
  use combat

create the Guardhouse
  a room

  A low stone guardhouse.

create the sentry
  a person, combatant with health 20 and skill 40
  in the Guardhouse

An expanse and a ship on it. The skiff is steered by compass heading or sent to a cell; the Marigold is turned by degrees and makes the pace her sailing row gives for her angle off the wind:

story
  title: Open Water
  authors:
    ref
  id: open-water
  story-version: 0.0.1
  use expanses
  use sailing

create the Sargasso
  an expanse
  size: 40 by 40
  wind: from northeast
  north is blocked: ice-fields

  Weed-choked water under a sky the colour of pewter.

  landmarks
    Port Royal: 3, 4
    the Reef: 12, 30
  end landmarks

create Port Royal
  a room
  seen from afar: a smudge of smoke over a low green shore
  sight: 20

  The quay.

create the Reef
  a room
  seen from afar: a line of white where the swell breaks

  Coral under a foot of water.

create the skiff
  a vehicle
  in the Sargasso at 3, 5
  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

  A skiff.

create the Marigold
  a vehicle
  in the Sargasso at 20, 20
  movement: open
  carries: in
  drive: player
  commands: naval
  stride: 1 unit
  sight: 8
  seen from afar: three masts leaning to the wind
  sails: furled, reefed, full
  sails start: furled

  A barque.

  sailing
    0 to 44 degrees: furled stopped, reefed stopped, full stopped
    45 to 74 degrees: furled stopped, reefed 6 turns, full 4 turns
    75 to 119 degrees: furled stopped, reefed 3 turns, full 2 turns
    120 to 180 degrees: furled 6 turns, reefed 2 turns, full 1 turn
    calm: stopped
  end sailing

create the cask
  a thing, floats
  in the Sargasso at 22, 20

  A tarred cask, riding low.

define phrase ice-fields
  Ice closes the way north.
end phrase

Aboard the skiff, steer east and set course for 12, 30 move it; look names what is in sight by band and direction, examine a landmark shows its seen from afar: line, and the step whose path crosses the cask's cell stops alongside it for retrieve cask. Aboard the Marigold, starboard 15 degrees turns her, ahead puts her under way, make sail sets more canvas, and dead into the wind she lies in irons until turned out or the story writes set the Sargasso's wind to southwest. The Sargasso's unwritten edges are weather for her; the written one is ice.