rolling/unrolling ranges in list, rev.0

params_or_stdin() { [ $# -eq 0 ] && cat || echo "$@"; }

list_unroll_int() {
  tr -s ',' '\n' \
  | tr -s '-' ' ' \
  | while read -a L; do
    [ ${#L[@]} -eq 1 ] && echo ${L[@]} && continue
    echo ${L[@]} | xargs -rn2 seq
  done \
  | sort -n \
  | paste -sd ',' -
}
list_unroll() { params_or_stdin "$@" | list_unroll_int; }

list_roll_int2() {
  local a b c d
  while read c; do
    [ -z "$a" ] && { a=$c; b=$c; }
    d=$[c-b]
    if [ $d -lt 2 ]; then
      [ $d -eq 1 ] && b=$c
      continue
    fi
    [ $[b-a] -gt 0 ] && echo "$a-$b" || echo "$a"
    a=$c; b=$c
  done
  [ $[b-a] -gt 0 ] && echo "$a-$b" || echo "$a"
}
list_roll_int() {
  tr -s ',' ' ' \
  | tr -s '[:space:]' '\n' \
  | uniq -u \
  | sort -n \
  | list_roll_int2 \
  | paste -sd ',' -
}
list_roll() { params_or_stdin "$@" | list_roll_int; }

list_unroll 1-5,13,9
#output: 1,2,3,4,5,9,13

list_roll 1 2 3 4 6 10 8 14 11
#output: 1-4,6,8,10-11,14