CODEWITHSUNDEEP
swift
amida
amida

Reputation: 97

Does Swift have anything resembling C++ references?

Suppose that some potentially large block of code needs to work with an array which is either array A or array B. Instead of writing

switch (x) {
case a:
  arrayA.append(X)
case b:
  arrayB.append(X)
}

I would like to write something like the following C++ code:

auto& arr = (x == a ? arrayA : arrayB);
arr.push_back(X);

Of course in real life the cases aren't that simple, but I hope you get the point: I would like to set up the reference just once and after that not care about which array I am working with.

Upvotes: 1

Views: 111

Answers (1)

Antonio
Antonio

Reputation: 72760

I am not aware of any way to obtain an array pointer - the only case where a reference is passed around is to a function parameter, using the inout modifier.

However closures are very flexible and usable in several ways - I think this is one of those cases. The idea is to create 2 closures, the 1st appending to arrayA, the 2nd to arrayB, then store the closure you want to use in a variable, and use it:

typealias PushToArrayClosure = (value: Int) -> Void

var arrayA = [1, 2, 3]
var arrayB = [4, 5, 6]
let condition = false

let pushA = { (value: Int) in
    arrayA.append(value)
}

let pushB = { (value: Int) in
    arrayB.append(value)
}

let pushToArray: PushToArrayClosure = condition ? pushA : pushB

pushToArray(value: 7)

arrayA // contains [1, 2, 3]
arrayB // contains [4, 5, 6, 7]

Upvotes: 1

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