version: 1
name: Test GPS receiver device
description: |
  Test the `whereami` command and GPS receiver device.
  https://github.com/swarm-game/swarm/issues/956
objectives:
  - condition: |
      loc <- as base {whereami};
      return $ loc == (0,0)
    goal:
      - |
        The goal is to move back to the origin after being
        unceremoniously teleported to a random location.  The only way
        to do this is to use a GPS receiver device to learn the
        current location and use the result to decide how to move.
solution: |
  def x = \n. \c. if (n == 0) {} {c ; x (n-1) c} end;
  def abs = \n. if (n<0) {-n} {n} end;
  wait 2;
  loc <- whereami;
  turn (if (fst loc < 0) {east} {west}); x (abs (fst loc)) move;
  turn (if (snd loc < 0) {north} {south}); x (abs (snd loc)) move;
robots:
  - name: base
    dir: [0,1]
    loc: [-5,5]
    devices:
      - clock
      - dictionary
      - GPS receiver
      - treads
      - compass
      - ADT calculator
      - strange loop
      - comparator
      - calculator
      - branch predictor
      - logger
  - name: teleporter
    dir: [0,1]
    loc: [0,0]
    system: true
    display:
      invisible: true
    program: |
      x <- random 11;
      y <- random 11;
      teleport base (x-5, y-5)
world:
  default: [blank]
  palette:
    '.': [grass]
  upperleft: [-5, 5]
  map: |
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........
    ...........