Is there a way to override “property” setters and getters in Swift?

Question

After reading @property/@synthesize equivalent in swift , I became curious for how the functionality from Objective C was retained.

Say I have the following in Objective C:

@interface MyClass
@property (readwrite) MyType *myVar;
@end

This can be accessed like such with dot- and smalltalk-based syntaxes:

Type *newVar1 = myClassInstance.myVar;
Type *newVar2 = [myClassInstance myVar];

myClassInstance.myVar = newVar1;
[myClassInstance setMyVar: newVar2];

And if I want to add some additional functionality to those getters/setters, I can do this:

@implementation MyClass

- (MyType *) myVar
{
    // do more stuff
    return self._myVar;
}

- (void) setMyVar: (MyType *) newVar
{
    self._myVar = newVar;
    // do more stuff
}

@end

_{(see also Custom setter for @property? )}

However, the accepted answer to the above linked question says that Swift doesn't differentiate between properties and instance variable. So, say I have the following in Swift:

class MyClass {
    var myVar: MyType
}

As far as I know, the only way to access myVar is as such:

var newVar1 = myClassInstance.myVar;

myClassInstance.myVar = newVar1;

But I don't know how to customize these getters and setters. Is there a Swift equivalent of the Objective C @property overrides?

Answer 1

While researching this question, I actually happened upon my answer, but still figured it should be put here for anyone else with the same question.

---

Yes, according to the Swift Programming Language documentation's page on Properties , getters and setters can be made in a similar way to how C# tackles the problem:

struct MyParentType {
    var myPlainVar: MyType = MyType()
    
    var myCustomGetterVar: MyType {
        // do more stuff
        return self.myCustomGetterVar
    }
    
    var myCustomGetterSetterVar: MyType {
        get {
            // do more stuff
            return self.myCustomGetterSetterVar
        }
        set {
            // do stuff
            self.myCustomGetterSetterVar = newValue
            // do more stuff
        }
    }
    
    var myCustomFancyVar: MyType? {
        willSet {
            // do stuff with newValue
        }
        // actual setting is done automatically, so no set{}
        didSet {
            // do more stuff with oldValue
        }
    }
}

Note that variables with didSet must be initialized or optional, and cannot have a get , since properties which are computed with get can easily implement their own didSet and willSet if they so choose.