Example of how to use Swift Reflection API against object property values

ReflectionProperties.swift

/*
 Initialized variables to defaults to avoid having to create
 initializers to keep things simple.
 */
class Superuser {
    var canUseSudo: Bool = false
}

class User: Superuser {
    var name: String = ""
    var address: String = ""
    var age: Int = 0
}

func isPersonValid(person: User) -> String?
{
    var stringValue: String?
    let mirrorPerson = Mirror(reflecting: person)

    mirrorPerson.children.forEach { (property) in
        if (property.value as? String)?.isEmpty == true || (property.value as? Int) == 0 {
            stringValue = property.label // The label here will be the property's name
        }
    }
    return stringValue
}

func isSuperPersonValid(person: User) -> String?
{
    var stringValue: String?
    guard let superUserMirror = Mirror(reflecting: person).superclassMirror() else { return "Cannot reflect superclass \(person.dynamicType)"
    }
    superUserMirror.children.forEach { (property) in
        if (property.value as? Bool) == true {
            stringValue = property.label
        }
    }
    return stringValue
}

let john = User()
john.address = "Somewhere in Neverland"
john.age = 24
john.canUseSudo = true

let validationString = isPersonValid(john)
if validationString != nil {
    print("Property not valid for \(validationString!)")
}

let sudoValidation = isSuperPersonValid(john)
if sudoValidation != nil {
    print("This user is trying to be all powerful. This isn't right..")
}