curry+partial

Curry.kt

operator fun <P1, P2, R> ((P1, P2) -> R).invoke(): (P1) -> (P2) -> R {
  return {p1: P1 -> { p2: P2 -> this(p1, p2) } }
}

operator fun <P1, P2, P3, R> ((P1, P2, P3) -> R).invoke(): (P1) -> (P2) -> (P3) -> R {
  return {p1: P1 -> { p2: P2 -> { p3: P3 -> this(p1, p2, p3) }}}
}

fun add(p1: Int, p2: Int): Int = p1 + p2

fun addCurry(): Int {
  return (::add)()(1)(2)
}

Partial.kt

operator fun <P1, P2, R> ((P1, P2) -> R).invoke(p1: P1): (P2) -> R {
  return { p2: P2 -> this(p1, p2) }
}

operator fun <P1, P2, P3, R> ((P1, P2, P3) -> R).invoke(p1: P1): (P2, P3) -> R {
  return { p2: P2, p3: P3 -> this(p1, p2, p3) }
}

fun addThree(p1: Int, p2: Int, p3: Int): Int = p1 + p2 + p3

fun addThreePartial(): Int {
  return (::addThree)(1)(2)(3)
}