Kotlin invoke()

1 개요

Kotlin invoke()

class Invokable {
    var numberOfInvocations: Int = 0
        private set
    operator fun invoke(): Invokable {
        numberOfInvocations++
        return this
    }
}

fun invokeTwice(invokable: Invokable) = invokable()()

class Foo {
    var count = 0;
    operator fun invoke(): Foo {
        count++
        return this
    }
}
fun main(args: Array<String>) {
    val foo = Foo()
    foo()()()()
    println("foo.count = [${foo.count}]")
    // foo.count = [4]
}

class Foo {
    var count = 0;
    operator fun invoke(): Foo {
        count++
        return this
    }
}
fun invokeTwice(foo: Foo) = foo()()
fun main(args: Array<String>) {
    val foo1 = Foo()
    val foo2 = invokeTwice(foo1)
    println("foo1.count=[${foo1.count}]") 
    println("foo2.count=[${foo2.count}]")
    // foo1.count=[2]
    // foo2.count=[2]
}

2 참고

• https://dzone.com/articles/learning-kotlin-invoke