def perm_go

bend-collections-laws-math@1.0.0.0 · src/math/natural.bend:125

import Base

125# n * (n - 1) * ... * (n - k + 1)
126def perm_go(k: Nat, +m: Nat, +acc: Nat) -> Nat:
127  match k:
128    case 0n:
129      acc
130    case 1n+j:
131      perm_go(j, Nat.sub(m, 1n), Nat.mul(acc, m))