class Builder::XmlMarkup

def declare!(inst, *args, &block)
  _indent
  @target << "<!#{inst}"
  args.each do |arg|
    case arg
    when ::String
      @target << %{ "#{arg}"} # " WART
    when ::Symbol
      @target << " #{arg}"
    end
  end
  if ::Kernel::block_given?
    @target << " ["
    _newline
    _nested_structures(block)
    @target << "]"
  end
  @target << ">"
  _newline
end