Bigint.Mag.group: def of bend-kit-bignum@0.1.0.0
Import: import bend-kit-bignum@0.1.0.0/bigint.bend as Bigint
Lines 325-337 of bend-kit-bignum@0.1.0.0/bigint.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-bignum@0.1.0.0/bigint.bend&start_line=325&end_line=337

import Base

# Digits, least significant first, four to a limb.
def Mag.group(ds: List<&2, U32>) -> List<&2, U32>:
  match ds:
    case Con{a, Con{b, Con{c, Con{d, t}}}}:
      Con{(a + 10 * b + 100 * c + 1000 * d : U32), Mag.group(t)}
    case Con{a, Con{b, Con{c, Nil{}}}}:
      Con{(a + 10 * b + 100 * c : U32), Nil{}}
    case Con{a, Con{b, Nil{}}}:
      Con{(a + 10 * b : U32), Nil{}}
    case Con{a, Nil{}}:
      Con{a, Nil{}}
    case Nil{}:
      Nil{}

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.mul