~repos /plum

module std

type Float =
  E = 2.718f  `Euler's number, the base of natural logarithms, e, https://oeis.org/A001113
  LN10 = 2.302f `The natural logarithm of 10, https://oeis.org/A002392
  LN2 = 0.693f `The natural logarithm of 2 https://oeis.org/A002162
  LOG10E = 0.434f `The base 10 logarithm of e `formula: 1 / LN10
  LOG2E = 1.442f `The base 2 logarithm of e `formula: 1 / LN2
  PI = 3.14159f `The ratio of the circumference of a circle to its diameter https://oeis.org/A000796
  PHI = 1.6180f `https://oeis.org/A001622
  SQRT1_2 = 0.707f `The square root of 1/2
  SQRT2 = 1.414f `The square root of 2 https://oeis.org/A002193
  SQRT_E = 1.64872f `https://oeis.org/A019774
  SQRT_PI  = 1.77245f `https://oeis.org/A002161
  SQRT_PHI = 1.27201f `https://oeis.org/A139339
  EPSILON = 2.220446049250313e-16f `The difference between 1 and the smallest floating point number greater than 1 formula: 7/3 - 4/3 - 1
  MIN_FLOAT_VALUE = 4.9406564584124654417656879286822137236505980e-324 `Lowest value of float
  MAX_FLOAT_VALUE = 1.79769313486231570814527423731704356798070e+308   `Highest value of float


  static fromStr(s: Str) -> Result(Float, Err) =
    todo

  acosh(v: Float) -> Float =
    match
      x < 1 | IsNaN(x) => NaN() # first case is special case
      x == 1 => 0
      x >= Large => x.log() + LN2 # x > 2**28
      x > 2 => Log(2*x - 1/(x+Sqrt(x*x-1))) # 2**28 > x > 2
      _ =>
        t =
        ((2*t+t*t).sqrt() + t).log1p() 2 >= x > 1

  `Check whether this number is finite, ie not +/-infinity and not NaN.
  `True if exponent is not all 1s
  isFinite() -> Bool =
    (bits() && 0x7FF0_0000_0000_0000) != 0x7FF0_0000_0000_0000

  `Check whether this number is +/-infinity
  `True if exponent is all 1s and mantissa is 0
  isInfinite() -> Bool =
    ((bits() && 0x7FF0_0000_0000_0000) == 0x7FF0_0000_0000_0000) &&  # exp
    ((bits() && 0x000F_FFFF_FFFF_FFFF) == 0)  # mantissa

  `Check whether this number is NaN.
  `True if exponent is all 1s and mantissa is non-0
  isNaN() -> Bool =
    ((bits() && 0x7FF0_0000_0000_0000) == 0x7FF0_0000_0000_0000) &&  # exp
    ((bits() && 0x000F_FFFF_FFFF_FFFF) != 0)  # mantissa

  toStr() -> Str =
    todo