enum_associated_values.swift

enum EmailValidationError {
    // TODO: - Cases
    case empty
    // TODO: - Cases can be declared on a single line
    case noDomain(String)
    case invalid(String)
}

// TODO: - Create a new error
var error = EmailValidationError.empty
// TODO: - OR type-inferred
var signupError: EmailValidationError = .invalid("maxxxxxxx.com")
error = .noDomain("max@")

// MARK: - Matching

switch error {
case .empty:
    print("Please provide email")
case .noDomain(let email):
    print("Add domain: \(email)")
case .invalid(let email):
    print("Entered email looks like invaid: \(email)")
}

if case let .invalid(email) = signupError {
    print("Entered email looks like invaid: \(email)")
}