gistfile1.scala

class Matrix extends Function2[Int, Int, Float] {
  import Matrix.{ width, height }

  private val e = new Array[Float](width * height)
  def apply(row : Int, col : Int) = e(row * width + col)
  def update(row : Int, col : Int, value : Float) { e(row * width + col) = value }

  def initializeWith(f : (Int, Int) => Float) = {
    for {
      row <- 0 until height
      val ofs = row * width
      col <- 0 until width
    } e(ofs + col) = f(row, col)
    this
  }
  def identity() = initializeWith((r, c) => if (r == c) 1f else 0f)
  // ...
}

object Matrix {
  final val width = 4
  final val height = 4
  def apply() = new Matrix identity
  def apply(m : Matrix) = new Matrix initializeWith m
}