1  require 'rexml/parsers/streamparser'
   2  require 'rexml/parsers/baseparser'
   3  require 'rexml/light/node'
   4 
   5  module REXML
   6    module Parsers
   7      class LightParser
   8        def initialize stream
   9          @stream = stream
  10          @parser = REXML::Parsers::BaseParser.new( stream )
  11        end
  12 
  13        def add_listener( listener )
  14          @parser.add_listener( listener )
  15        end
  16 
  17        def rewind
  18          @stream.rewind
  19          @parser.stream = @stream
  20        end
  21 
  22        def parse
  23          root = context = [ :document ]
  24          while true
  25            event = @parser.pull
  26            case event[0]
  27            when :end_document
  28              break
  29            when :end_doctype
  30              context = context[1]
  31            when :start_element, :start_doctype
  32              new_node = event
  33              context << new_node
  34              new_node[1,0] = [context]
  35              context = new_node
  36            when :end_element, :end_doctype
  37              context = context[1]
  38            else
  39              new_node = event
  40              context << new_node
  41              new_node[1,0] = [context]
  42            end
  43          end
  44          root
  45        end
  46      end
  47 
  48      # An element is an array.  The array contains:
  49      #  0      The parent element
  50      #  1      The tag name
  51      #  2      A hash of attributes
  52      #  3..-1  The child elements
  53      # An element is an array of size > 3
  54      # Text is a String
  55      # PIs are [ :processing_instruction, target, data ]
  56      # Comments are [ :comment, data ]
  57      # DocTypes are DocType structs
  58      # The root is an array with XMLDecls, Text, DocType, Array, Text
  59    end
  60  end