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Implementing Custom Subscripts in Swift

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1

Learn how to extend your own types with subscripts, allowing you to index into them with simple syntax just like native arrays and dictionaries.

This is a companion discussion topic for the original entry at https://www.raywenderlich.com/1114-implementing-custom-subscripts-in-swift
2

Awesome tutorial! Very helpful and informative indeed. I have one question though, I was following with no problems up until the second subscript implementation.

subscript(x: Int, y: Int) -> Square {
  get {
    return self[(x: x, y: y)]
  }
  set {
    self[(x: x, y: y)] = newValue
  }
}

I don’t quite understand how does the self[(x: x, y: y)] part works, in this case how does Swift knows we are referring to the squares array?

If someone could elaborate on this it would be awesome, thank you!

3

Swift knows we are referring to the squares array, because you defined a subscript that takes a coordinate above. You are using the setter of the first subscript in this case.

4

This tutorial is more than six months old so questions regarding it are no longer supported for the moment. We will update it as soon as possible. Thank you! :]