version: 1
name: Overlay with erasure
description: |
  Test that we can erase entities when overlaying
objectives:
  - condition: |
      as base { n <- count "tree"; return (n == 0) }
    goal:
    - Get rid of your trees.
solution: |
  place "tree"; move; move;
  place "tree"; move; move;
  place "tree"; move; move;
  place "tree"
robots:
  - name: base
    loc: [0,0]
    dir: [1,0]
    devices:
      - logger
      - treads
      - grabber
    inventory:
      - [4, tree]
world:
  dsl: |
    overlay
    [ {terrain: ice} <> {entity: tree}
    , if (x + y) % 2 == 0 then {erase} else {blank}
    ]