Cannot assign to property: 'xxxx' is a get-only property

Question

I\'m using a computed property to get the last book in my books array. However, it seems I can\'t use this property to directly set a book\'s position

Answer 1

The error occurs because you did not tell the compiler what to do if the value of currentBook is mutated. The compiler assumes it is immutable.

Just add a setter so that the compiler knows what to do when you set the value:

var currentBook: Book {
    get { return books[books.count - 1] }
    set { books[books.count - 1] = newValue }
}

Or, consider using books.last!:

books.last!.position = CGPoint.zero