Swift Builder

Builder.swift

import Foundation

protocol Buildable {
    init()
    init(_ build: (inout Self) -> Self)
}

extension Buildable {
    init(_ build: (inout Self) -> Self) {
        var s = Self()
        self = build(&s)
    }
}

struct Pet {
    var name: String
    var age: Int
    var owner: Person?
}

extension Pet: Buildable {
    init() {
        self = Pet(name: "N/A", age: 0, owner: nil)
    }
}

struct Person {
    var name: String
    var age: Int
}

extension Person: Buildable {
    init() {
        self = Person(name: "N/A", age: 0)
    }
}

var test = Person()
test.name = "Jabroni"
test.age = 34

let test2 = Person( { (person) -> Person in
    person.name = "leif"
    person.age = 23
    return person
})

print(test2)

let petOne = Pet {
    $0.name = "Doggo"
    $0.age = 3
    $0.owner = test2
    return $0
}

print(petOne)

func print(person: Person) {
    print("Printing: \(person)")
}

print(person: Person {
    $0.name = "Nice"
    return $0
})