version: 1
name: Define
description: |
  Learn how to define new commands.
objectives:
  - goal:
      - Your goal is to build a robot to fetch the flower growing in the
        upper right and bring it back to you; you win the challenge when the base
        has a flower in its inventory.
      - |
        However, it would be extremely tedious to simply type out all the individual
        `move` and `turn` commands required.  Your base has a `dictionary` device
        that can be used to define new commands.  For example:
      - |
        def m4 : cmd unit = move; move; move; move end
      - defines a new command `m4`, with type `cmd unit`, as four consecutive `move` commands.
        With judicious
        use of new definitions, it should be possible to complete this challenge
        in just a few lines of code.
      - |
        TIP: your base is at coordinates (0,0), and the flower is at (16,4), which
        you can confirm by clicking in the world map panel. When you click on a cell,
        its contents and coordinates are shown in the lower left.
      - |
        TIP: the type annotation in a definition is optional.  You could also write
        `def m4 = move; move; move; move end`, and Swarm would infer
        the type of `m4`.
      - |
        TIP: writing function definitions at the prompt is annoying.
        You can also put definitions in a `.sw` file and load it
        with the `run` command. Check out
        https://github.com/swarm-game/swarm/tree/main/editors
        for help setting up an external editor with things like
        syntax and error highlighting.
    condition: |
      try {
        as base {has "flower"}
      } { return false }
solution: |
  def m2 = move; move end;
  def m4 = m2; m2 end;
  def m8 = m4; m4 end;
  def m16 = m8; m8 end;
  def tL = turn left end;
  def tR = turn right end;
  def tB = turn back end;
  def S = m16; tL; m2; tL; m16; tR; m2; tR; m16 end;
  build {
    turn right; S; f <- harvest; tB; S; give base f
  }
robots:
  - name: base
    dir: [0,1]
    display:
      char: Ω
      attr: robot
    devices:
      - logger
      - 3D printer
      - dictionary
    inventory:
      - [10, logger]
      - [10, compass]
      - [10, scanner]
      - [10, treads]
      - [10, solar panel]
      - [10, harvester]
      - [10, grabber]
      - [0, flower]
known: [boulder]
world:
  default: [blank]
  palette:
    'Ω': [grass, null, base]
    '.': [grass]
    '*': [grass, flower]
    '@': [grass, boulder]
    '┌': [stone, upper left corner]
    '┐': [stone, upper right corner]
    '└': [stone, lower left corner]
    '┘': [stone, lower right corner]
    '─': [stone, horizontal wall]
    '│': [stone, vertical wall]
  upperleft: [-1, 5]
  map: |
    ┌─────────────────┐
    │................*│
    │.@@@@@@@@@@@@@@@@│
    │.................│
    │@@@@@@@@@@@@@@@@.│
    │Ω................│
    └─────────────────┘