class Oddb2xml::Builder

def prepare_substances
  unless @substances
    Oddb2xml.log("prepare_substances from #{@items.size} items")
    @substances = []
    @items.values.uniq.each do |seq|
      next unless seq[:substances]
      seq[:substances].each do |sub|
        @substances << sub[:name]
      end
    end
    @substances.uniq!
    @substances.sort!
    Oddb2xml.log("prepare_substances done. Total #{@substances.size} from #{@items.size} items")
    exit 2 if (@options[:extended] || @options[:artikelstamm]) && (@substances.size == 0)
  end
end