smalltalk.kt

import kotlin.ranges.*
 
// While
fun whileTrueRepeat(target: () -> Boolean, body: () -> Unit): Unit {
  if (target()) {
    body()
    whileTrueRepeat(target, body)
  }
}

infix fun (() -> Boolean).whileTrue(body: () -> Unit): Unit {
  whileTrueRepeat(this, body)
}

// If/else
interface ITestValue {
  infix fun ifTrue(body: () -> Unit): ITestValue
  infix fun ifFalse(body: () -> Unit): ITestValue
}

object TrueValue: ITestValue {
  override infix fun ifTrue(body: () -> Unit): ITestValue {
    body()
    return this
  }

  override infix fun ifFalse(body: () -> Unit): ITestValue = this
}

object FalseValue: ITestValue {
  override infix fun ifTrue(body: () -> Unit): ITestValue = this

  override infix fun ifFalse(body: () -> Unit): ITestValue {
    body()
    return this
  }
}

infix fun Boolean.ifTrue(body: () -> Unit): ITestValue {
  if (this) {
    body()
    return TrueValue
  }
  return FalseValue
}

infix fun Boolean.ifFalse(body: () -> Unit): ITestValue {
  if (!this) {
    body()
    return FalseValue
  }
  return TrueValue
}

// For
infix fun IntProgression.loop(body: (value: Int) -> Unit): Unit {
  for (v in this) {
      body(v)
  }
}

infix fun LongProgression.loop(body: (value: Long) -> Unit): Unit {
  for (v in this) {
      body(v)
  }
}

infix fun CharProgression.loop(body: (value: Char) -> Unit): Unit {
  for (v in this) {
      body(v)
  }
}

// Repeat
infix fun Int.timesRepeat(body: () -> Unit): Unit {
    for (i in 0 until this) {
        body()
    }
}

infix fun Long.timesRepeat(body: () -> Unit): Unit {
    for (i in 0 until this) {
        body()
    }
}

// tests
fun main() {
  var i = 0
  { i < 10 } whileTrue {
      i++
      println(i)
  }
  
  (1 < 10) ifTrue {
    println("1 < 10")
  } ifFalse {
    println("1 >= 10")
  }
  
  (1 < 0) ifTrue {
    println("1 < 0")
  } ifFalse {
    println("1 >= 0")
  }
  
  11..20 loop { v ->
  	println(v)
  }
  
  3 timesRepeat {
      println("hello!")
  }
}