Natural.pow_mod_odd: def of bend-collections-laws-math@1.0.0.0
Import: import bend-collections-laws-math@1.0.0.0/src/math/natural.bend as Natural
Lines 275-282 of bend-collections-laws-math@1.0.0.0/src/math/natural.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-math@1.0.0.0/src/math/natural.bend&start_line=275&end_line=282

import Base

# right-to-left binary exponentiation, reducing mod m after every product:
# acc * base^e == b^e0 (mod m) throughout
def pow_mod_odd(+m: Nat, +bit: Nat, +base: Nat, +acc: Nat) -> Nat:
  match bit:
    case 0n:
      acc
    case 1n+z:
      Nat.mod(Nat.mul(acc, base), m)

Uses (3):
  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
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.mul