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iOS Object-Oriented Swift Classes and Objects Classes and Their Methods

Posted by fmquaglia
fmquaglia
11,060 Points

Is there some sort of performance drawback if you decide to keep using the self keyword?

Is there some sort of performance drawback (or any other problem or code smell) if you decide to keep using the self keyword to refer to the instance's properties within your methods even if there isn't any naming conflict?

E.G.:

class Product  {
    let title : String
    let price : Double

    init(title: String, price: Double) {
        self.title = title
        self.price = price
    }

    func discountedPrice(percentage: Double) -> Double {
        return price - price * percentage / 100
    }
}

vs.

class Product  {
    let title : String
    let price : Double

    init(title: String, price: Double) {
        self.title = title
        self.price = price
    }

    func discountedPrice(percentage: Double) -> Double {
        return self.price - self.price * percentage / 100
    }
}

2 Answers

Stephen Whitfield
Stephen Whitfield
16,771 Points

There shouldn't be a drawback... especially if it's a derivative from objective-C for accessing class properties and also Apple's preferred method for accessing class properties.

fmquaglia
fmquaglia
11,060 Points

Thanks @stephenwhitfield ! Your answer is clear.

X. Szuh
X. Szuh
2,486 Points
X. Szuh
X. Szuh
2,486 Points

Self refers to an instance of an object. I think you are misunderstanding why it is needed.

fmquaglia
fmquaglia
11,060 Points

Hi Deanne Chance ,

No, not at all. I come from a Ruby background, where the keyword to refer to the object itself is also "self". So it's pretty clear to me what self is about. "Know your self" ;-)

Even further I use to create a variable in OO Javascript called to self, to refer to the object's "this" and not the private methods's "this"

function Foo() {
  var self = this;
  self.bar = null;
  function baz() {
    // using this here would refer to baz's scope, so self to the rescue
   self.bar = "bazified";
 }
}

What I am asking is if compiled swift code would get a memory or processor hit using self to refer object's properties within methods.

Thanks anyway! :-)