CODEWITHSUNDEEP
scaladslinfix-notation
mert inan
mert inan

Reputation: 1597

Scala:Implicit converters & infix notation & operator precedence

Please excuse me if you find the supplied code beyond the scope of the question. At the bottom of the code s1 (500.m + 10.km) toKm expression compiles successfully but the it does not look natural. Is there anyway we can achieve this syntax (500 m + 10 km) toKm?

object Main extends App {
  sealed trait Measure {
    def toM: M = this match {
      case Km(km) => M(km * 1000)
      case m: M   => m
    }

    def toKm: Km = this match {
      case M(m)   => Km(m / 1000)
      case km: Km => km
    }
  }
  case class Km(val m: Double) extends Measure {
    def +(that: Any): Km = {
      that match {
        case Km(rhs) => Km(m + rhs)
        case M(rhs)  => Km(m + rhs / 1000)
      }
    }
    override def toString() = m + " km"
  }

  case class M(val m: Double) extends Measure {
    def +(that: Any): M = {
      that match {
        case Km(rhs) => M(m + rhs * 1000)
        case M(rhs)  => M(m + rhs)
      }
    }

    override def toString() = m + " m"
  }

  implicit class MeasureConverter(val measure: Double) extends AnyVal {
    def km = new Km(measure)
    def m = new M(measure)
  }

  val s1 = (500.m + 10.km) toKm

  val s2 = (500 m + 10 km) toKm

}

Upvotes: 0

Views: 396

Answers (1)

Nikita Volkov
Nikita Volkov

Reputation: 43309

Due to Scala's syntactic rules you'll need to enclose those in brackets.

((500 m) + (10 km)) toKm

For code style consistency and other reasons I would however advise against ever using infix notation for anything other than symbolic operators (+ in this case), i.e.:

(500.m + 10.km).toKm

Upvotes: 1

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