         let col = columnNum
         let lvl = logLevel
         
-        print("\(date) \(file) : \(fun) : \(line) : \(col) \(lvl) \(msg)")
+        if let h = howToLog {
+            h(logLevel: lvl, msg: msg, fileName: file, functionName: fun, lineNum: line, columnNum: col)
+        } else {
+            print("\(date) \(file) : \(fun) : \(line) : \(col) \(lvl) \(msg)")
+        }
     }
 }
 

import Foundation

public class SwiftLog {
    /// log level. Print logs which >= logLevel
    public var logLevel: LogLevel
    /// date format

    }
    
    /**
    execute log.
    If you want to custom log format, change howToLog.
    
    - parameter logLevel:     logLevel
    - parameter msg:          msg
