>>932
ちょっとリファクタリング(ってほど大層じゃないが)
selectargnum() {
 func="$1"; start=$2; length=$3
 shift 3
 i=0; last=$((start + length))
 for arg in "$@"; do
  i=$((i + 1))
  test ${i} -gt ${length} && shift
  test ${i} -ge ${last} && continue
  shift
  set -- "$@" "${arg}"
 done
 "${func}" "${@}"
}