Game smart constructor

GameSmartConstructor.kt

typealias State = List<List<Symbol>>
fun State.toGame(): Game = Game.of(this)
...
sealed class Game(val state: State) {
  companion object {
    ...
    fun of(state: State): Game {
      val winningCells =
        (rows + columns + diagonals)
          .map { coordinates -> state.values(coordinates) }
          .firstOrNull { it.allSymbolsMatch(CROSS) || it.allSymbolsMatch(NOUGHT) }
          .orEmpty()
      val isDrawn by lazy { state.all { it.none { symbol -> symbol == BLANK } } }
      return when {
        winningCells.isNotEmpty() -> Won(state, winningCells.first().second)
        isDrawn -> Draw(state)
        else -> InProgress(state)
      }
    }
    ...
  }
}