LeibnizFormula.scala

import scala.compiletime.ops.int
import scala.compiletime.ops.double

type F1[A <: Int] <: Double =
  int.%[A, 2] match
    case 0 =>
      1d
    case 1 =>
      -1d

type F2[A <: Int] =
  double./[
    F1[A],
    int.ToDouble[
      int.+[
        int.*[A, 2],
        1
      ]
    ]
  ]

type F3[A <: Int, B <: Double] <: Double =
  int.<[A, 0] match {
    case true =>
      double.*[4.0, B]
    case false =>
      F3[int.-[A, 1], double.+[B, F2[A]]]
  }

type F[A <: Int] = F3[A, 0.0]

def x = summon[F[10000] =:= 3.1416926435905435]