Generate the 3-2-3 pattern GUID used by an Xcode storyboard id attribute. Useful for templating.

StoryBoardGUIDGenerator.swift

import Foundation

class StoryBoardGUIDGenerator {
    
    private let legalChars: [Character] = {
        let lower = "abcdefghiklmnopqrstuvwxyz"
        let upper = "ABCDEFGHIKLMNOPQRSTUVWXYZ"
        let number = "0123456789"
        let legal = lower+upper+number
        return Array(legal)
    }()
    
    private func randomChar() -> String {
        let index = Int(arc4random_uniform(UInt32(legalChars.count)))
        let char = legalChars[index]
        return String(char)
    }
    
    private func randomFragment(length: Int) -> String {
        guard length > 0 else {
            return ""
        }
        var part = ""
        for _ in 1...length {
            let comp = randomChar()
            part += comp
        }
        return part
    }
    
    func guid() -> String {
        let comps = [randomFragment(length: 3),randomFragment(length: 2),randomFragment(length: 3)]
        return comps.joined(separator: "-")
    }
}