Bool関連のStringをBoolに変換するExtension

Purpose

Personal Note
あんまり使いませんが使用する機会があったのでとりあえずメモ

Development Environment

• OS X El Captain 10.11.2
• Xcode Version 8.0

Language

Swift 3.0

Code

extension String {    
    func toBool() -> Bool? {
        switch self {
        case "TRUE", "True", "true", "YES", "Yes", "yes", "1":
            return true
        case "FALSE", "False", "false", "NO", "No", "no", "0":
            return false
        default:
            return nil
        }
    }
}