#!/bin/sh

# Use factor(1) and bc(1) to output all divisors for a number
# This is proposed to be added to factor(1) through the -a,--all option

test "$1" == '--help' && { echo 'Usage: divisors [NUMBER]...'; exit; }

factor "$@" |
while read -r label factors
do
  printf '%s ' "$label"
  set -- $factors

  {
    printf '
define d(i,x) {
  auto j,y,z
  j=i
  while (j<%d && p[j]==p[i]) j=j+1
  y=x
  while (1) {
    if (j==%d) y else z=d(j,y)
    if (i==j) return(0)
    y=y*p[i]
    i=i+1
  }
}\n' "$#" "$#"

    i=0
    for p; do
      printf 'p[%d]=%s\n' "$i" "$p"
      i=$(($i + 1))
    done

    printf 'z=d(0,1)\n'
  } |
  BC_LINE_LENGTH=0 bc |
  sort -n |
  paste -sd ' '
done