795-prerequisite-mutually-exclusive.yaml

version: 1
name: |
  Mutually exclusive prerequisites
description: |
  Complete an objective with a prerequisite of either of two other objectives.
objectives:
  - goal:
      - Either obtain a "furnace" WITHOUT a "flower", or obtain both a "wooden gear" and "flower".
    condition: |
      return true;
    prerequisite:
      previewable: true
      logic:
        or:
          - and:
            - id: have_furnace
            - not:
                id: have_flower
          - and:
            - id: have_gear
            - id: have_flower
  - id: have_furnace
    goal:
      - Make a "furnace".
    condition: |
      as base {has "furnace"};
    
    optional: true
  - id: have_gear
    goal:
      - Make a "wooden gear".
    condition: |
      as base {has "wooden gear"};
    optional: true
  - id: have_flower
    goal:
      - Possess a "flower".
    condition: |
      as base {has "flower"};
    optional: true
solution: |
  make "furnace"
robots:
  - name: base
    display:
      char: 'Ω'
      attr: robot
    dir: [0, 1]
    devices:
      - workbench
      - grabber
    inventory:
      - [2, board]
      - [5, rock]
world:
  default: [blank]
  palette:
    'x': [grass, flower, base]
  upperleft: [0, 0]
  map: |
    x