ls (PDF::Reader::Explore)

    # File lib/pdf/reader/explore.rb, line 86
        def ls (entry = nil)
          parts = @pwd.split('/')
          obj   = @root

          parts.shift if parts[0] == ""
          parts.push(entry) if entry

          parts.each do |p|
            case obj
            when Hash
              unless obj.has_key?(p)
                puts "invalid path at #{p}"
                return
              end
              obj = obj[p]

            when Array
              obj = obj[p.to_i]
            end

            obj = @xref.object(obj)
          end

          output_parent(obj)
          "#{@pwd}: #{obj.class}"
        end