file.rb

  def _simple_compress(nodes)
    # dedup nodes
    set = {}
    nodes.each do |node|
      set[node] = true
    end
    nodes = set.keys
    nodes = _sort_nodes(nodes)

    result = []
    prev_prefix, prev_digits, prev_suffix =  "", nil, ""
    prev_n = nil
    count = 0

    nodes.each do |n|
      if n =~ /\A#{@@NodeRegx}\z/
        # foo100abc => foo 100 abc
        prefix, digits, suffix = $1, $2, $3
        prefix = "" if prefix.nil?
        suffix = "" if suffix.nil?
      else
        prefix, digits, suffix = n, nil, nil
      end
      if (not digits.to_i.zero?) and
          (prefix == prev_prefix) and
          (suffix == prev_suffix) and
          (not prev_digits.nil?) and
          (digits.to_i == prev_digits.to_i + count + 1)
        count += 1
        next
      end
      
      if prev_n
        if count > 0
          result << _get_group(prev_prefix, prev_digits, count, prev_suffix)
        else
          result << prev_n
        end
      end
      prev_n = n
      prev_prefix = prefix
      prev_digits = digits
      prev_suffix = suffix
      count = 0
    end #nodes.each

    if count > 0
      result << _get_group(prev_prefix, prev_digits, count, prev_suffix)
    else
      result << prev_n
    end
    return result.join ","
  end