あ、間違った値が作られないについてですが、 struct Line: Hashable { let start: Coordinate let end: Coordinate let direction: Direction let distance: Distance init?(start: Coordinate, direction: Direction, distance: Distance) { // NOTE: Be nil if the X is out of boards. let unsafeX: CoordinateX? switch direction { case .top, .bottom: unsafeX = start.x case .left, .topLeft, .bottomLeft: unsafeX = CoordinateX(rawValue: start.x.rawValue - distance.rawValue) case .right, .topRight, .bottomRight: unsafeX = CoordinateX(rawValue: start.x.rawValue + distance.rawValue) } // NOTE: Be nil if the Y is out of boards. let unsafeY: CoordinateY? switch direction { case .left, .right: unsafeY = start.y case .top, .topLeft, .topRight: unsafeY = CoordinateY(rawValue: start.y.rawValue - distance.rawValue) case .bottom, .bottomLeft, .bottomRight: unsafeY = CoordinateY(rawValue: start.y.rawValue + distance.rawValue) } switch (unsafeX, unsafeY) { case (.none, _), (_, .none): return nil case (.some(let x), .some(let y)): self.start = start self.end = Coordinate(x: x, y: y) self.direction = direction self.distance = distance } }
