commons mathf {
  fn half(x: Float) -> Float {
    x / 2.0
  }

  fn intDiv(a: Int, b: Int) -> Int {
    a / b
  }

  fn area(w: Float, h: Float) -> Float {
    w * h
  }

  fn isHalf(x: Float) -> Bool {
    x == 0.5
  }

  fn demo() -> Bool {
    let x = 5.0 / 2.0
    let n = 5 / 2
    let e = 1.5e-3
    let big = 1e10
    isHalf(x - 2.0) && n == 2 && e > 0.0 && big >= 1.0 && area(2.0, 3.5) != 7.5
  }
}
