Expressive Kotlin

expressive-kotlin.kt

package org.jrenner.tactical.utils

import com.badlogic.gdx.utils.TimeUtils

object Timer {
    enum class TimeUnit(val name: String) {
        Seconds : TimeUnit("seconds")
        Millis : TimeUnit("millis")
        Micros : TimeUnit("micros")
        Nanos : TimeUnit("nanos")

        fun humanTime(nanoTime: Long): String {
            val mult = when (this) {
                Seconds -> 1 / 1000000000f
                Millis  -> 1 / 1000000f
                Micros  -> 1 / 1000f
                Nanos   -> 1f
            }
            val precision = when (this) {
                Seconds -> "2"
                else    -> "0"
            }
            return "%.${precision}f ${name}".format(nanoTime.toFloat() * mult)
        }

    }
    fun measure(func: () -> Unit, name: String = "timer") {
        val start = TimeUtils.nanoTime()
        func()
        val time = TimeUtils.timeSinceNanos(start)
        println("[timer: $name]: ${TimeUnit.Millis.humanTime(time)}")        
    }

    fun example() {
        val myFunc = { for (i in 1..1000) println("hello") }
        Timer.measure(myFunc, "hello printer")
        // output: [timer: hello printer]: 33 millis
    }
}

Or other ways to play with this:
https://gist.github.com/jaysonminard/a496cc60416c01044628