version: 1
name: Towers of Hanoi
author: Ondřej Šebek and Brent Yorgey
description: The classic Towers of Hanoi puzzle with three disks.
objectives:
  - goal:
      - Move all the numbers (traditionally, "disks") from the
        left column to the right column.
      - You may only pick up one disk at a time, and you may never
        place a larger disk on top of a smaller one.
    condition: |
      teleport self (2,-1);
      x <- ishere "one";
      teleport self (2,-2);
      y <- ishere "blocked two";
      teleport self (2,-3);
      z <- ishere "blocked three";
      return (x && y && z)
solution: |
  run "scenarios/Challenges/hanoi-solution.sw"
robots:
  - name: base
    dir: [0,-1]
    devices:
      - net
      - treads
      - logger
      - grabber
      - dictionary
      - branch predictor
      - comparator
      - strange loop
      - compass
      - clock
      - scanner
      - ADT calculator
  - name: invariant
    dir: [0,0]
    system: true
    devices:
    - logger
    inventory:
    - [1, one]
    - [1, two]
    - [1, three]
    - [1, blocked one]
    - [1, blocked two]
    - [1, blocked three]
    program: |
      // if
      //  0. I stand on locked X
      //  1. place north of me is empty
      //  2. all disks are placed
      //  3. other columns are sorted (check "OK")
      // then
      //  - unlock X
      // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      // if
      //  0. I stand on unlocked X
      //  1. place noth of me is NOT empty
      // then
      //  - lock X
      run "scenarios/Challenges/hanoi-invariant.sw"
  - name: increasing
    dir: [0,0]
    system: true
    inventory:
    - [1, OK]
    devices:
    - logger
    program: |
      // if
      //  0. all (but max 3) disks in my column are sorted
      // then
      //  - place "OK"
      // else
      //  - try to grab "OK"
      run "scenarios/Challenges/hanoi-increasing.sw"
  - name: count
    dir: [0,0]
    system: true
    inventory:
    - [1, two]
    - [0, three]
    devices:
    - logger
    program: |
      // count all entities placed in columns
      // the final count should be either 2 or 3
      // place "two" or "three" at x=0 y=-6
      run "scenarios/Challenges/hanoi-count.sw"
entities:
  - name: bottom tee
    display:
      char: '┴'
      attr: entity
    description:
    - A bottom tee wall.
    properties: [unwalkable]
  - name: three
    display:
      char: '3'
      attr: gold
    description:
    - A disk of radius 3.
    properties: [portable]
  - name: two
    display:
      char: '2'
      attr: gold
    description:
    - A disk of radius 2.
    properties: [portable]
  - name: one
    display:
      char: '1'
      attr: gold
    description:
    - A disk of radius 1.
    properties: [portable]
  - name: blocked one
    display:
      char: '1'
      attr: entity
    description:
    - A disk of radius 1.
    properties: [unwalkable]
  - name: blocked two
    display:
      char: '2'
      attr: entity
    description:
    - A disk of radius 2.
    properties: [unwalkable]
  - name: blocked three
    display:
      char: '3'
      attr: entity
    description:
    - A disk of radius 3.
    properties: [unwalkable]
  - name: OK
    display:
      char: 'O'
      attr: gold
    description:
      - This entity signals that the column is sorted.
known:
  - bottom tee
  - OK
  - one
  - two
  - three
  - blocked one
  - blocked two
  - blocked three
world:
  default: [grass, null]
  palette:
    ' ': [grass]
    '_': [stone]
    'v': [stone, null, base]
    '┌': [stone, upper left corner]
    '┐': [stone, upper right corner]
    '└': [stone, lower left corner]
    '┘': [stone, lower right corner]
    '─': [stone, horizontal wall]
    '│': [stone, vertical wall]
    '┴': [stone, bottom tee]
    '1': [stone, one, invariant]
    '2': [stone, blocked two, invariant]
    '3': [stone, blocked three, invariant]
    '.': [stone, null, invariant]
    '^': [grass, null, increasing]
    'X': [grass, three, count]

  upperleft: [-3, 1]
  map: |
    ┌─────┐
    │__v__│
    │1│.│.│
    │2│.│.│
    │3│.│.│
    └─┴─┴─┘
     ^ ^ ^ 
       X