Natural.gcd_go: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/src/math/natural.bend as Natural
Lines 49-57 of bend-collections-laws-crypto@1.0.0.0/src/math/natural.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/src/math/natural.bend&start_line=49&end_line=57

import Base

# Euclid's algorithm; b <= fuel throughout (every step lowers b).
def gcd_go(fuel: Nat, +a: Nat, +b: Nat) -> Nat:
  match fuel b:
    case 0n _:
      a
    case 1n+f 0n:
      a
    case 1n+f 1n+ +bp:
      gcd_go(f, 1n+bp, Nat.mod(a, 1n+bp))

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.mod