Natural.factorial: def of bend-collections-laws-math@1.0.0.0
Import: import bend-collections-laws-math@1.0.0.0/spec/math/natural.bend as Natural
Lines 51-57 of bend-collections-laws-math@1.0.0.0/spec/math/natural.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-math@1.0.0.0/spec/math/natural.bend&start_line=51&end_line=57

import Base

# Mathlib/Data/Nat/Factorial/Basic (Nat.factorial_succ)
def factorial(n: Nat) -> Nat:
  match n:
    case 0n:
      1n
    case 1n+ +p:
      Nat.mul(1n+p, factorial(p))

Uses (2):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.mul