Swift Protocol Logger with level condition, Swift 2.X and Swift 3.X version

HCLog_Playground_V2.swift

//: Playground - noun: a place where people can play

// Usage for Swift 2.X using the deadly old Swift Debugger Identifiers, ie: __FILE__
// @see: https://github.com/apple/swift-evolution/blob/master/proposals/0028-modernizing-debug-identifiers.md

enum LogLevel: Int {
    case verbose = 1
    case debug = 2
    case info = 3
    case warning = 4
    case error = 5
}

func >=(lhs: LogLevel, rhs: LogLevel) -> Bool {
    return lhs.rawValue >= rhs.rawValue
}


protocol Log {
    
    /// Writes a log entry. Types that
    /// conform to `Log` must implement
    /// this to perform their work.
    ///
    /// - Important: Clients of `Log`
    ///   should never call this method.
    ///   Always call `log(_:,_:)`.
    func writeLogEntry(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString,
        line: Int,
        function: StaticString)
    
}

extension Log {
    
    /// The public API for `Log`. Calls
    /// `writeLogEntry(_:,_:,file:,line:,function:)`.
    
    func log(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString  = __FILE__,
        line: Int = __LINE__,
        function: StaticString = __FUNCTION__)
        {
        writeLogEntry(logLevel, message,
        file: file, line: line,
        function: function)

    }
    
}

struct HCLog {
    
    let minimumLogLevel: LogLevel
    
}

extension HCLog: Log {
    
    func writeLogEntry(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString,
        line: Int,
        function: StaticString)
    {
        if logLevel >= minimumLogLevel {
            print("\(logLevel) – \(file):\(line) – \(function) – \(message())")
        }
    }
    
}

HCLog_Playground_V3.swift

//: Playground - noun: a place where people can play

// Usage for Swift 3.X using the brand new Swift Debugger Identifiers, is: #file
// @see: https://github.com/apple/swift-evolution/blob/master/proposals/0028-modernizing-debug-identifiers.md

enum LogLevel: Int {
    case verbose = 1
    case debug = 2
    case info = 3
    case warning = 4
    case error = 5
}

func >=(lhs: LogLevel, rhs: LogLevel) -> Bool {
    return lhs.rawValue >= rhs.rawValue
}


protocol Log {
    
    /// Writes a log entry. Types that
    /// conform to `Log` must implement
    /// this to perform their work.
    ///
    /// - Important: Clients of `Log`
    ///   should never call this method.
    ///   Always call `log(_:,_:)`.
    func writeLogEntry(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString,
        line: Int,
        function: StaticString)
    
}

extension Log {
    
    /// The public API for `Log`. Calls
    /// `writeLogEntry(_:,_:,file:,line:,function:)`.
    
    func log(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString  = #file,
        line: Int = #line,
        function: StaticString = #function)
        {
        writeLogEntry(logLevel, message,
        file: file, line: line,
        function: function)

    }
    
}

struct HCLog {
    
    let minimumLogLevel: LogLevel
    
}

extension HCLog: Log {
    
    func writeLogEntry(
        logLevel: LogLevel,
        @autoclosure _ message: () -> String,
        file: StaticString,
        line: Int,
        function: StaticString)
    {
        if logLevel >= minimumLogLevel {
            print("\(logLevel) – \(file):\(line) – \(function) – \(message())")
        }
    }
    
}

HCLog_Usage.swift

let logger = HCLog(minimumLogLevel: .error)

logger.log(.verbose, "this is a verbose test") // NOPE ⛔️

logger.log(.error, "This is a error test") // 🎉

logger.log(.error, "This is another error test") // 🎉