pedrocid

//Exercises from https://www.pointfree.co/episodes/ep9-algebraic-data-types-exponents

import UIKit

enum Either<A,B> {
    case left(A)
    case right(B)
}

struct Pair<A,B> {

pedrocid

import UIKit

class Thing {
    
    var name: String
    var quantity: Int
    
    init(name: String, quantity: Int){
    
        self.name = name

pedrocid

//MARK: From https://mikeash.com/pyblog/friday-qa-2015-11-20-covariance-and-contravariance.html

import UIKit

//MARK: TYPE VARIANCE LESSON

//First we explore supertypes and subtypes

class Thing {}
class Vehicle: Thing {}

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//MARK: Abstract factory pattern

protocol AbstractProductA{

    func display() -> String
}

protocol AbstractProductB{
    
    func display() -> String

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struct ObjectToConstruct {
    
    let propertyOne: String?
    let propertyTwo: Array<String>?
    let propertyThree: Bool?
}


class ConstructBuilder {