Lens Sample in Scalaz

LensSample.scala

import scalaz._, Scalaz._

case class Position(x: Int, y: Int)
case class Panel(position: Position, obj: String)

val px = Lens.lensu[Position, Int]( (pos, _x) => pos.copy(x = _x), _.x)
/*
val px = Lens.lensu[Position, Int] (
  (pos: Position, tmpX: Int) => pos.copy(x = tmpX),
  (pos: Position)            => pos.x
)
*/

val py = Lens.lensu[Position, Int]( (pos, _y) => pos.copy(y = _y), _.y)
/*
val px = Lens.lensu[Position, Int] (
  (pos: Position, tmpY: Int) => pos.copy(y = tmpY),
  (pos: Position)            => pos.y
)
*/

val fp = Lens.lensu[Panel, Position]( (panel, pos) => panel.copy(position = pos), _.position)
val fo = Lens.lensu[Panel, String]( (panel, o) => panel.copy(obj = o), _.obj)


// initial data
val zero = Position(0, 0)
val zeroPanel = Panel(zero, "@")



// --- Sample1 ---
scala> px.get(zero)
res7: Int = 0

scala> py.set(zero, 100)
res9: Position = Position(0,100)

scala> py.mod(_ + 5, zero)
res11: Position = Position(0,5)


// --- Sample2 ---
scala> fp.get(zeroPanel)
res15: Position = Position(0,0)

scala> fo.get(zeroPanel)
res16: String = @


// --- Sample3 ---

// same andThen
val fpx = fp >=> px

// same compose
val fpy = py <=< fp

scala> fpx.get(zeroPanel)
res18: Int = 0

scala> fpy.set(zeroPanel, 99)
res19: Panel = Panel(Position(0,99),@)