version: 1
name: Sniff test
creative: true
description: Locate a tree using sniff
objectives:
  - goal:
      - grab a tree.
    condition: |
      as base {has "tree"}
solution: |
  def homeIn = \item. \oldDistance.
    if (oldDistance > 0) {
      move;
      newDistance <- sniff item;
      d <- if (newDistance > oldDistance) {
        turn back;
        move;
        turn left;
        return oldDistance;
      } {
        return newDistance;
      };
      homeIn item d;
    } {
      grab;
    }
    end;

  let item = "tree" in
  initialDistance <- sniff item;
  homeIn item initialDistance;
robots:
  - name: base
    dir: [0,-1]
    display:
      char: Ω
      attr: robot
    devices:
      - logger
      - string
      - grabber
      - treads
known: []
world:
  palette:
    'Ω': [grass, null, base]
    '.': [grass]
    'T': [grass, tree]
  upperleft: [0, 0]
  map: |
   .........
   ......T..
   .........
   .........
   .Ω.......
   .........