A simple hash > XML converter using REXML

hash2xml.rb

class ::Hash
	require "rexml/document"
	def to_xml(indent: nil, rootname: nil, output: nil, encoding: nil)
		indent = indent ? indent : 2
		rootname = rootname ? rootname : "root"
		output = output == $stdout ? $stdout : nil
		encoding = encoding ? encoding : "UTF-8"
		xml = REXML::Document.new
		formatter = REXML::Formatters::Pretty.new(indent)
		formatter.compact = true

		process_block(key: rootname, block: self, xml: xml)
		xml << REXML::XMLDecl.new("1.0", "utf-8")

		if output == $stdout
			formatter.write(xml, $stdout)
		else
			output = ""
			formatter.write(xml, output)
			return output
		end
	end

	private
	def process_block(key: nil, block: nil, xml: nil)
		if block.is_a?(Hash)
			attributes = find_attributes(block: block)
			attributes.each { |key, value| block.delete(key) }
			item = attributes.length > 0 ? xml.add_element(key, attributes) : xml.add_element(key)
			block.each do |key, value|
			process_block(key: key, block: value, xml: item)
			end
		elsif block.is_a?(Array)
			block.each do |element|
			process_block(key: key, block: element, xml: xml)
			end
		else
			item = xml.add_element(key)
			item.text = block.to_s
		end
	end

	def find_attributes(block: nil)
		attributes = {}
		block.each do |key, value|
			attributes[key] = value if (not value.is_a?(Array) and not value.is_a?(Hash))
		end
		return attributes
	end
end