DSL for game world and level declaration

GameWorld.swift

class GameWorld {
    var systems: [System] = []
    var entities: [Entity] = []
    var terrain: Terrain?
    var level: Level?
    var player: Player?

    // Add a system to the game world
    func addSystem(_ system: System) {
        systems.append(system)
    }

    // Add an entity to the game world
    func addEntity(_ entity: Entity) {
        entities.append(entity)
    }

    // Set the terrain for the game world
    func setTerrain(_ terrain: Terrain) {
        self.terrain = terrain
    }

    // Set the level for the game world
    func setLevel(_ level: Level) {
        self.level = level
    }

    // Set the player for the game world
    func setPlayer(_ player: Player) {
        self.player = player
    }

    // Start the game world and all its systems
    func start() {
        systems.forEach { $0.start() }
    }

    // Stop the game world and all its systems
    func stop() {
        systems.forEach { $0.stop() }
    }
}

GameWorldDSL.swift

// Define the game world
let gameWorld = GameWorld()

// Define the game level
let level = GameLevel()

// Define the terrain for the level
level.terrain = Terrain()
    .withSize(width: 100, height: 50)
    .withTexture(imageNamed: "grass_texture")
    .withPhysics(enabled: true)

// Define the enemy spawning system for the level
level.enemySpawner = EnemySpawner()
    .withEnemyType(type: .basicEnemy)
    .withSpawnRate(rate: 2.0)
    .withMaxEnemies(max: 10)

// Define the player character for the level
level.player = PlayerCharacter()
    .withTexture(imageNamed: "player_texture")
    .withHealth(max: 100)
    .withSpeed(value: 5.0)

// Define the collectibles for the level
level.collectibles = Collectibles()
    .withCollectibleType(type: .coin)
    .withSpawnRate(rate: 1.0)

// Add the level to the game world
gameWorld.add(level: level)

// Define the physics system for the game world
gameWorld.physicsSystem = PhysicsSystem()
    .withGravity(value: 9.8)

// Define the animation system for the game world
gameWorld.animationSystem = AnimationSystem()

// Define the input system for the game world
gameWorld.inputSystem = InputSystem()
    .withSwipeGesture(direction: .up)
    .withSwipeGesture(direction: .down)
    .withSwipeGesture(direction: .left)
    .withSwipeGesture(direction: .right)
    .withTapGesture()

// Start the game
gameWorld.start()

LevelTerrainPlayer.swift

import SceneKit

struct Level {
    var terrain: Terrain
    var player: Player
}

struct Terrain {
    var node: SCNNode
}

struct Player {
    var node: SCNNode
    var speed: Float
    var jumpHeight: Float
}