data class Leaf(var green: Int)

fun autumn() = Leaf(100)
    .let { leaf ->    // dawn brings forth new life
        leaf.also {    // chlorophyll fades slowly now
            it.green -= 50   // autumn takes its toll
        }.apply { green = 0  // golden turns to brown at last
        }.also { null }      // returns to the earth's embrace 
    }

Lifecycle Tanka

Created: 2011
Creator: JetBrains Team led by Andrey Breslav
Key Influences: Java, Scala, Groovy, C#, JavaScript, Python

fun String?.contemplateExistence() = when {
    this == null -> "What exists in nothing?"
    isEmpty() -> "Is empty truly empty?"
    else -> "Form is not different from emptiness"
}

fun main() {
    val void: String? = null
    val emptiness = ""
    val form = "being"

    println(void.contemplateExistence())
    println(emptiness.contemplateExistence())
    println(form.contemplateExistence())
}

Kotlin

History

Paradigms