Is there an Kotlin equivalent `with` function in Swift?

Question

In Kotlin, we could change the below

// Original code
var commonObj = ClassCommonObj()
 commonObj.data1 = dataA
 commonObj.data2 = dataB
 commonObj.data3 = dataC

// Improved code
var commonObj = ClassCommonObj()
with(commonObj) {
    data1 = dataA
    data2 = dataB
    data3 = dataC
}

However in Swift as below, do I have equivalent with function to use?

// Original code
var commonObj = ClassCommonObj()
 commonObj.data1 = dataA
 commonObj.data2 = dataB
 commonObj.data3 = dataC

Answer 1

Unfortunately, no such functionality so far in Swift. However, similar functionality can be reached with the power of extensions:

protocol ScopeFunc {}
extension ScopeFunc {
    @inline(__always) func apply(block: (Self) -> ()) -> Self {
        block(self)
        return self
    }
    @inline(__always) func with<R>(block: (Self) -> R) -> R {
        return block(self)
    }
}

This protocol and extension provides two inline functions, where one can be served to return processed object, and the other is strictly similar to with in Kotlin and other languages (Visual Basic supported in 90s).

Usage

Specify types which these functions should apply to:

extension NSObject: ScopeFunc {} 

apply:

let imageView = UIImageView().apply {
    $0.contentMode = .scaleAspectFit
    $0.isOpaque = true
}

Here we create an object and once the closure is executed, modified object is returned.

with:

imageView.with {
    $0.isHidden = true
}

Works equal to with in Kotlin.

Originaly based on this source code.

NOTE:

Swift compiler is generally regarded as smart enough to decide whether or not a function should be inlined. Quite likely, these two would be inlined due to their relative compactness even without strictly specifying @inline (__always). Either way, you should know that this keyword does not affect the logic and the result of these, because inlining is about optimizing the program.