strategy-pattern-2.swift

 
// What
protocol LoggerStrategy {
    func log(_ message: String)
}

// Who
struct Logger {
    let strategy: LoggerStrategy

    func log(_ message: String) {
        strategy.log(message)
    }
}

// How
struct LowercaseStrategy: LoggerStrategy {
    func log(_ message: String) {
        print(message.lowercased())
    }
}

struct UppercaseStratgy: LoggerStrategy {
    func log(_ message: String) {
        print(message.uppercased())
    }
}

struct CapitalizedStrategy: LoggerStrategy {
    func log(_ message: String) {
        print(message.capitalized)
    }
}