biboudis / dotty Goto Github PK

import scala.annotation.mirror

object mirrors {
  @mirror def +(A: Int, B: Int): Int & Singleton = A + B
}

import scala.annotation.mirror

object mirrors {
  @mirror def +(A: Int, B: Int): Int = A + B

  type Singleton[T] = T

  def singlify[T](implicit x: T): T = x
}

import mirrors._

class Vector[+N <: Int : Singleton](val innerArray: List[Int]) {
  def size: N = singlify[N]

  def concat[M <: Int](vec: Vector[M]): Vector[N + M] =
    new Vector[N + M](innerArray ++ vec.innerArray)(mirrors.+(size, vec.size))
}

object Test {
  def main(args: Array[String]): Unit = {
    implicit def length1: 1 = 1
    implicit def length2: 2 = 2
    val vec1: Vector[1] = new Vector[1](List(1))
    val vec2: Vector[2] = new Vector[2](List(2, 3))

    val vec3: Vector[3] = vec1.concat(vec2)
  }
}

val vec3: Vector[3] = vec1.concat(vec2)

val vec3: Vector[1 + 2] = vec1.concat(vec2)
val vec4: Vector[3] = vec3