pavermakov

extension String {
    func camelCaseToSnakeCase() -> String {
        let acronymPattern = "([A-Z]+)([A-Z][a-z]|[0-9])"
        let normalPattern = "([a-z0-9])([A-Z])"
        return self.processCamalCaseRegex(pattern: acronymPattern)?
            .processCamalCaseRegex(pattern: normalPattern)?.lowercased() ?? self.lowercased()
    }
    
    fileprivate func processCamalCaseRegex(pattern: String) -> String? {
        let regex = try? NSRegularExpression(pattern: pattern, options: [])

pavermakov

/*
        DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE 
                    Version 2, December 2004 

 Copyright (C) 2016 Esa-Matti Suuronen <esa-matti@suuronen.org> 

 Everyone is permitted to copy and distribute verbatim or modified 
 copies of this license document, and changing it is allowed as long 
 as the name is changed.