string by incremented trailing number good for a suggestion of duplicated file name

String+incrementingTrailingNumber.swift

//	String+Z.swift
//	ZKit
//
//	The MIT License (MIT)
//
//	Copyright (c) 2016 Electricwoods LLC, Kaz Yoshikawa.
//
//	Permission is hereby granted, free of charge, to any person obtaining a copy
//	of this software and associated documentation files (the "Software"), to deal
//	in the Software without restriction, including without limitation the rights
//	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//	copies of the Software, and to permit persons to whom the Software is
//	furnished to do so, subject to the following conditions:
//
//	The above copyright notice and this permission notice shall be included in
//	all copies or substantial portions of the Software.
//
//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//	WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//	THE SOFTWARE.
//
//	Usage:
//		"0".incrementingTrailingNumber() // "1"
//		"1".incrementingTrailingNumber() // "2"
//		"Untitled".incrementingTrailingNumber() // "Untitled2"
//		"Untitled1".incrementingTrailingNumber() // "Untitled2"
//		"Untitled2".incrementingTrailingNumber() //  "Untitled3"
//		"Untitled-3".incrementingTrailingNumber() // "Untitled-4"
//		"Untitled 3".incrementingTrailingNumber() // "Untitled 4"

import Foundation


public extension String {
	
	func incrementingTrailingNumber() -> String {
		if let range = self.range(of: "[0-9]+$", options: [.regularExpression]), let number = Int(self[range]) {
			return self.replacingCharacters(in: range, with: String(number + 1))
		}
		return self + "2"
	}
	
}