#! /bin/sh
###
### Expand a list of symbolic references to other lists.

expand () {
  slaves=""
  for i in "$@"; do
    case "$i" in
      :*)
        name=${i#:}
        eval found=\${set_$name+t}\${set_$name-nil} set=\${set_$name}
        case "$found" in
          nil) echo >&2 "$0: no such set \`$name'"; exit 1 ;;
        esac
        slaves="$slaves $set"
        ;;
      *)
        slaves="$slaves $i"
        ;;
    esac
  done
  echo $slaves
}

defset () {
  setname=$1; shift
  eval set_$setname='$(expand "$@")'
}

case $# in
  0 | 1)
    echo >&2 "Usage: $0 FILE ITEM|:LIST ..."
    exit 1
    ;;
esac

. "$1"; shift
expand "$@"