Mini Shell

require 'rexml/parsers/streamparser'
require 'rexml/parsers/baseparser'

module REXML
	module Parsers
		class UltraLightParser
			def initialize stream
				@stream = stream
				@parser = REXML::Parsers::BaseParser.new( stream )
			end

      def add_listener( listener )
        @parser.add_listener( listener )
      end

      def rewind
        @stream.rewind
        @parser.stream = @stream
      end

			def parse
				root = context = []
				while true
					event = @parser.pull
					case event[0]
					when :end_document
						break
					when :end_doctype
						context = context[1]
					when :start_element, :doctype
						context << event
						event[1,0] = [context]
						context = event
					when :end_element
						context = context[1]
					else
						context << event
					end
				end
				root
			end
		end

		# An element is an array.  The array contains:
		#  0			The parent element
		#  1			The tag name
		#  2			A hash of attributes
		#  3..-1	The child elements
		# An element is an array of size > 3
		# Text is a String
		# PIs are [ :processing_instruction, target, data ]
		# Comments are [ :comment, data ]
		# DocTypes are DocType structs
		# The root is an array with XMLDecls, Text, DocType, Array, Text
	end
end