// a.scala
// Sat Oct 29 10:06:51 PDT 2011
package simple
import scala.{Double=>double, Int=>int}
/**
* @author Christoph Radig
*/
trait Vector {
def xd: double
def yd: double
}
object Vector {
def apply(x: double, y: double) = Double(x, y)
def apply(x: int, y: int) = Int(x, y)
trait Companion[@specialized(double, int) T] {
type I <: Instance[T]
def apply(x: T, y: T): I // I (= this.type#I) or this.I?
lazy val zero: I = apply(numeric.zero, numeric.zero)
val numeric: Numeric[T]
}
trait Instance[@specialized(double, int) T] extends Vector {
type C <: Companion[T]
def companion: C
def numeric: Numeric[T] = companion.numeric
val x: T
val y: T
def xd = numeric.toDouble(x)
def yd = numeric.toDouble(y)
def + (that: C#I): C#I = companion(numeric.plus(this.x, that.x), numeric.plus(this.y, that.y))
def - (that: C#I): C#I = companion(numeric.minus(this.x, that.x), numeric.minus(this.y, that.y))
/**
* scalar multiplication
*/
def * (scalar: T): C#I = companion(numeric.times(this.x, scalar), numeric.times(this.y, scalar))
}
object Double extends Companion[double] {
type I = Double
def apply(x: double, y: double) = new Double(x, y)
val numeric = Numeric.DoubleIsFractional
}
final class Double(val x: double, val y: double) extends Instance[double] {
type C = Double.type
def companion = Double
@inline override def xd = x
@inline override def yd = y
}
object Int extends Companion[int] {
type I = Int
def apply(x: int, y: int) = new Int(x, y)
val numeric = Numeric.IntIsIntegral
}
final class Int(val x: int, val y: int) extends Instance[int] {
type C = Int.type
def companion = Int
}
}
