let approx_eq = (v1, v2, epsilon) => {
  abs_float (v1 -. v2) < epsilon
}

let test = (a, b) => {
  let epsilon = 1e-18
  Printf.printf("%g, %g => %b\n", a, b, approx_eq(a, b, epsilon))
}

{
  test(100000000000000.01, 100000000000000.011)
  test(100.01, 100.011)
  test(10000000000000.001 /. 10000.0, 1000000000.0000001000)
  test(0.001, 0.0010000001)
  test(0.000000000000000000000101, 0.0)
  test(sqrt(2.0) *. sqrt(2.0), 2.0)
  test(-. sqrt(2.0) *. sqrt(2.0), (-2.0))
  test(3.14159265358979323846, 3.14159265358979324)
}