Scala 中的简单隐式转换

Question

I'm pretty new to scala and I really love it so far but I'm stuck with a really weird problem. I wanted to try implicit conversions by implementing D&D-style dice expressions. ie 2d12 "throw two twelve-sided dice"... you know what I mean.

From what I understand scala should be able to compile this

(1 d 6).roll

and probably even this

1d6 + 2 - 1d30

but I get a "value d is not a member of int" compile error in my specs test.

package meh.toast
import scala.util.Random

object Dice {
  class DiceSymbol(val amount:Int) {
    def d(sides:Int):Dice = new Dice(amount, sides)
  } 

  implicit def int2DiceSymbol(amount:Int) = new DiceSymbol(amount)
  implicit def dice2Int(d:Dice) = d.roll

  private val rnd = new Random()
  protected def throwDice(sides:Int) = rnd.nextInt(sides) + 1
}

class Dice(amount:Int, sides:Int) {
   def roll:Int = (1 to amount) map { _ => Dice.throwDice(sides)} sum 
}

I'm really stuck. It would be awesome if you could help, it's probably something really simple.

Thanks in advance

Answer 1

You're really close: but you have to make sure the implicit functions from the Dice object are in scope when you try to use them:

 scala> import Dice._
 import Dice._

 scala> (1 d 6).roll
 res12: Int = 2