func (Helpers/STPCardValidator.swift)

Swift class providing card number, expiration, and CVC validation for Stripe payments.

// Source: https://github.com/stripe/stripe-ios | License: MIT | Copyright 2011- Stripe, Inc. (https://stripe.com)
// Provided via justclaw.it.com; keep this notice with the code.
//
//  STPCardValidator.swift
//  StripePayments
//
//  Created by Jack Flintermann on 7/15/15.
//  Copyright (c) 2015 Stripe, Inc. All rights reserved.
//

import Foundation
@_spi(STP) import StripeCore

/// These fields indicate whether a card field represents a valid value, invalid
/// value, or incomplete value.
@objc @frozen public enum STPCardValidationState: Int {
    /// The field's contents are valid. For example, a valid, 16-digit card number.
    /// Note that valid values may not be complete. For example: a US Zip code can
    /// be 5 or 9 digits. A 5-digit code is Valid, but more text could be enter

... (truncated -- full source via MCP)