instance method collapse

# File activesupport/lib/active_support/vendor/xml-simple-1.0.11/xmlsimple.rb, line 461
  def collapse(element)
    result = @options['noattr'] ? {} : get_attributes(element)

    if @options['normalisespace'] == 2
      result.each { |k, v| result[k] = normalise_space(v) }
    end

    if element.has_elements?
      element.each_element { |child|
        value = collapse(child)
        if empty(value) && (element.attributes.empty? || @options['noattr'])
          next if @options.has_key?('suppressempty') && @options['suppressempty'] == true
        end
        result = merge(result, child.name, value)
      }
      if has_mixed_content?(element)
        # normalisespace?
        content = element.texts.map { |x| x.to_s }
        content = content[0] if content.size == 1
        result[@options['contentkey']] = content
      end
    elsif element.has_text? # i.e. it has only text.
      return collapse_text_node(result, element)
    end

    # Turn Arrays into Hashes if key fields present.
    count = fold_arrays(result)

    # Disintermediate grouped tags.
    if @options.has_key?('grouptags')
      result.each { |key, value|
        next unless (value.instance_of?(Hash) && (value.size == 1))
        child_key, child_value = value.to_a[0]
        if @options['grouptags'][key] == child_key
          result[key] = child_value
        end
      }
    end
    
    # Fold Hashes containing a single anonymous Array up into just the Array.
    if count == 1 
      anonymoustag = @options['anonymoustag']
      if result.has_key?(anonymoustag) && result[anonymoustag].instance_of?(Array)
        return result[anonymoustag]
      end
    end

    if result.empty? && @options.has_key?('suppressempty')
      return @options['suppressempty'] == '' ? '' : nil
    end

    result
  end