diff --git a/ChangeLog b/ChangeLog
index 0eb3bf4a0b..986045d9dd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,37 @@
+Fri Nov 19 17:18:17 2004  Kouhei Sutou  <kou@cozmixng.org>
+
+	* lib/rss/rss.rb (RSS::VERSION): 0.1.0 -> 0.1.1.
+
+	* lib/rss: #to_s used #tag.
+
+	* test/rss/test_to_s.rb: added.
+
+	* lib/rss/maker.rb (RSS::Maker.make): changed API. It's not
+	  received modules which is used as the second argument.
+
+	* lib/rss/xml-stylesheet.rb (RSS::XMLStyleSheet#alternate):
+	  changed return value type which is not String but Boolean.
+
+	* lib/rss/2.0.rb (RSS::Rss::Channel#ttl): changed return value
+	  type which is not String but Integer.
+	
+	* lib/rss/0.9.rb (RSS::Rss::Channel): <skipDays> has <day>s and
+	  <skipHours> has <hour>s.
+
+	* lib/rss/maker/0.9.rb (RSS::Maker::RSS09::Channel): ditto.
+
+	* lib/rss/0.9.rb (RSS::Rss::Channel::Item): <item> has <category>s.
+
+	* lib/rss/maker/2.0.rb (RSS::Maker::Rss20::Channel::Item): ditto.
+
+	* lib/rss/2.0.rb (RSS::Rss::Channel): <channel> has <category>s.
+
+	* lib/rss/maker/2.0.rb (RSS::Maker::RSS20::Channel): ditto.
+
+	* lib/rss/trackback.rb: parent element has <trackback:about>s.
+
+	* lib/rss/maker/trackback.rb: ditto.
+
 Fri Nov 19 11:10:16 2004  WATANABE Hirofumi  <eban@ruby-lang.org>
 
 	* lib/test/unit/collector/dir.rb: add support for directory name
diff --git a/lib/rss/0.9.rb b/lib/rss/0.9.rb
index c772e80870..20a229b926 100644
--- a/lib/rss/0.9.rb
+++ b/lib/rss/0.9.rb
@@ -60,17 +60,14 @@ module RSS
     end
     
     def to_s(convert=true, indent=calc_indent)
-      next_indent = indent + INDENT
-      rv = <<-EOR
-#{xmldecl}
-#{xml_stylesheet_pi}
-#{indent}<rss version="#{@rss_version}"#{ns_declaration(next_indent)}>
-#{channel_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</rss>
-EOR
+      rv = tag(indent, ns_declarations) do |next_indent|
+        [
+          channel_element(false, next_indent),
+          other_element(false, next_indent),
+        ]
+      end
       rv = @converter.convert(rv) if convert and @converter
-      remove_empty_newline(rv)
+      rv
     end
 
     private
@@ -86,7 +83,7 @@ EOR
 
     def _attrs
       [
-        ["version", true],
+        ["version", true, "rss_version"],
       ]
     end
 
@@ -104,8 +101,6 @@ EOR
         ["webMaster", "?"],
         ["rating", "?"],
         ["docs", "?"],
-        ["skipDays", "?"],
-        ["skipHours", "?"],
       ].each do |x, occurs|
         install_text_element(x)
         install_model(x, occurs)
@@ -120,6 +115,8 @@ EOR
       end
 
       [
+        ["skipDays", "?"],
+        ["skipHours", "?"],
         ["image", nil],
         ["textInput", "?"],
       ].each do |x, occurs|
@@ -146,35 +143,35 @@ EOR
       end
 
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        rv = <<-EOT
-#{indent}<channel>
-#{title_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{language_element(false, next_indent)}
-#{copyright_element(false, next_indent)}
-#{managingEditor_element(false, next_indent)}
-#{webMaster_element(false, next_indent)}
-#{rating_element(false, next_indent)}
-#{pubDate_element(false, next_indent)}
-#{lastBuildDate_element(false, next_indent)}
-#{docs_element(false, next_indent)}
-#{skipDays_element(false, next_indent)}
-#{skipHours_element(false, next_indent)}
-#{image_element(false, next_indent)}
-#{item_elements(false, next_indent)}
-#{textInput_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</channel>
-EOT
+        rv = tag(indent) do |next_indent|
+          [
+            title_element(false, next_indent),
+            link_element(false, next_indent),
+            description_element(false, next_indent),
+            language_element(false, next_indent),
+            copyright_element(false, next_indent),
+            managingEditor_element(false, next_indent),
+            webMaster_element(false, next_indent),
+            rating_element(false, next_indent),
+            pubDate_element(false, next_indent),
+            lastBuildDate_element(false, next_indent),
+            docs_element(false, next_indent),
+            cloud_element(false, next_indent),
+            skipDays_element(false, next_indent),
+            skipHours_element(false, next_indent),
+            image_element(false, next_indent),
+            item_elements(false, next_indent),
+            textInput_element(false, next_indent),
+            other_element(false, next_indent),
+          ]
+        end
         rv = @converter.convert(rv) if convert and @converter
         rv
       end
 
       private
       def children
-        [@image, @textInput, @cloud, *@item]
+        [@skipDays, @skipHours, @image, @textInput, @cloud, *@item]
       end
 
       def _tags
@@ -206,6 +203,101 @@ EOT
         rv
       end
 
+      class SkipDays < Element
+        include RSS09
+
+        [
+          ["day", "*"]
+        ].each do |x, occurs|
+          install_have_children_element(x)
+          install_model(x, occurs)
+        end
+
+        def to_s(convert=true, indent=calc_indent)
+          rv = tag(indent) do |next_indent|
+            [
+              day_elements(false, next_indent)
+            ]
+          end
+          rv = @converter.convert(rv) if convert and @converter
+          rv
+        end
+
+        private
+        def children
+          @day
+        end
+
+        def _tags
+          @day.compact.collect do
+            [nil, "day"]
+          end
+        end
+
+        class Day < Element
+          include RSS09
+
+          content_setup
+
+          def initialize(content=nil)
+            super()
+            @content = content
+          end
+      
+        end
+        
+      end
+      
+      class SkipHours < Element
+        include RSS09
+
+        [
+          ["hour", "*"]
+        ].each do |x, occurs|
+          install_have_children_element(x)
+          install_model(x, occurs)
+        end
+
+        def to_s(convert=true, indent=calc_indent)
+          rv = tag(indent) do |next_indent|
+            [
+              hour_elements(false, next_indent)
+            ]
+          end
+          rv = @converter.convert(rv) if convert and @converter
+          rv
+        end
+
+        private
+        def children
+          @hour
+        end
+
+        def _tags
+          @hour.compact.collect do
+            [nil, "hour"]
+          end
+        end
+
+        class Hour < Element
+          include RSS09
+
+          content_setup
+
+          def initialize(content=nil)
+            super()
+            @content = content
+          end
+
+          undef :content=
+          def content=(value)
+            @content = value.to_i
+          end
+          
+        end
+        
+      end
+      
       class Image < Element
 
         include RSS09
@@ -220,18 +312,17 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          next_indent = indent + INDENT
-          rv = <<-EOT
-#{indent}<image>
-#{url_element(false, next_indent)}
-#{title_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{width_element(false, next_indent)}
-#{height_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</image>
-EOT
+          rv = tag(indent) do |next_indent|
+            [
+              url_element(false, next_indent),
+              title_element(false, next_indent),
+              link_element(false, next_indent),
+              width_element(false, next_indent),
+              height_element(false, next_indent),
+              description_element(false, next_indent),
+              other_element(false, next_indent),
+            ]
+          end
        		rv = @converter.convert(rv) if convert and @converter
     	    rv
         end
@@ -245,7 +336,7 @@ EOT
           end
         end
       end
-      
+
       class Cloud < Element
 
         include RSS09
@@ -270,16 +361,8 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          next_indent = indent + INDENT
-          rv = <<-EOT
-#{indent}<cloud
-#{next_indent}domain="#{h @domain}"
-#{next_indent}port="#{h @port}"
-#{next_indent}path="#{h @path}"
-#{next_indent}registerProcedure="#{h @registerProcedure}"
-#{next_indent}protocol="#{h @protocol}"/>
-EOT
-       		rv = @converter.convert(rv) if convert and @converter
+          rv = tag(indent)
+          rv = @converter.convert(rv) if convert and @converter
     	    rv
         end
 
@@ -300,15 +383,21 @@ EOT
           install_text_element(x)
         end
 
-        %w(category source enclosure).each do |x|
+        %w(source enclosure).each do |x|
           install_have_child_element(x)
         end
 
+        [
+          %w(category categories),
+        ].each do |name, plural_name|
+          install_have_children_element(name, plural_name)
+        end
+        
         [
           ["title", '?'],
           ["link", '?'],
           ["description", '?'],
-          ["category", '?'],
+          ["category", '*'],
           ["source", '?'],
           ["enclosure", '?'],
         ].each do |tag, occurs|
@@ -316,34 +405,39 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          next_indent = indent + INDENT
-          rv = <<-EOT
-#{indent}<item>
-#{title_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{category_element(false, next_indent)}
-#{source_element(false, next_indent)}
-#{enclosure_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</item>
-EOT
-       		rv = @converter.convert(rv) if convert and @converter
+          rv = tag(indent) do |next_indent|
+            [
+              title_element(false, next_indent),
+              link_element(false, next_indent),
+              description_element(false, next_indent),
+              category_elements(false, next_indent),
+              source_element(false, next_indent),
+              enclosure_element(false, next_indent),
+              other_element(false, next_indent),
+            ]
+          end
+          rv = @converter.convert(rv) if convert and @converter
     	    rv
         end
 
         private
         def children
-          [@category, @source, @enclosure,].compact
+          [@source, @enclosure, *@category].compact
         end
 
         def _tags
-          %w(title link description author comments category
+          rv = %w(title link description author comments
             source enclosure).delete_if do |x|
             send(x).nil?
           end.collect do |x|
             [nil, x]
           end
+
+          @category.each do
+            rv << [nil, "category"]
+          end
+          
+          rv
         end
 
         class Source < Element
@@ -364,17 +458,6 @@ EOT
             @content = content
           end
 
-          def to_s(convert=true, indent=calc_indent)
-            if @url
-              rv = %Q!				<source url="#{@url}">!
-              rv << %Q!#{@content}</source>!
-              rv = @converter.convert(rv) if convert and @converter
-              rv
-            else
-              ''
-            end
-          end
-
           private
           def _tags
             []
@@ -408,14 +491,9 @@ EOT
           end
 
           def to_s(convert=true, indent=calc_indent)
-            if @url and @length and @type
-              rv = %Q!<enclosure url="#{h @url}" !
-              rv << %Q!length="#{h @length}" type="#{h @type}"/>!
-              rv = @converter.convert(rv) if convert and @converter
-              rv
-            else
-              ''
-            end
+            rv = tag(indent)
+            rv = @converter.convert(rv) if convert and @converter
+            rv
           end
 
           private
@@ -447,17 +525,6 @@ EOT
             @content = content
           end
 
-          def to_s(convert=true, indent=calc_indent)
-            if @domain
-              rv = %Q!<category domain="#{h @domain}">!
-              rv << %Q!#{h @content}</category>!
-              rv = @converter.convert(rv) if convert and @converter
-              rv
-            else
-              ''
-            end
-          end
-
           private
           def _attrs
             [
@@ -470,7 +537,7 @@ EOT
       end
       
       class TextInput < Element
-        
+
         include RSS09
 
         %w(title description name link).each do |x|
@@ -479,17 +546,16 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          next_indent = indent + INDENT
-          rv = <<-EOT
-#{indent}<textInput>
-#{title_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{name_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</textInput>
-EOT
-       		rv = @converter.convert(rv) if convert and @converter
+          rv = tag(indent) do |next_indent|
+            [
+              title_element(false, next_indent),
+              description_element(false, next_indent),
+              name_element(false, next_indent),
+              link_element(false, next_indent),
+              other_element(false, next_indent),
+            ]
+          end
+          rv = @converter.convert(rv) if convert and @converter
     	    rv
         end
 
diff --git a/lib/rss/1.0.rb b/lib/rss/1.0.rb
index 563ed66426..9a61e456ba 100644
--- a/lib/rss/1.0.rb
+++ b/lib/rss/1.0.rb
@@ -18,7 +18,6 @@ module RSS
 
     include RSS10
     include RootElementMixin
-    include XMLStyleSheetMixin
 
     class << self
 
@@ -57,21 +56,22 @@ module RSS
       super('1.0', version, encoding, standalone)
     end
 
+    def full_name
+      tag_name_with_prefix(PREFIX)
+    end
+    
     def to_s(convert=true, indent=calc_indent)
-      next_indent = indent + INDENT
-      rv = <<-EORDF
-#{xmldecl}
-#{xml_stylesheet_pi}
-#{indent}<#{PREFIX}:RDF#{ns_declaration(next_indent)}>
-#{channel_element(false, next_indent)}
-#{image_element(false, next_indent)}
-#{item_elements(false, next_indent)}
-#{textinput_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</#{PREFIX}:RDF>
-EORDF
+      rv = tag(indent, ns_declarations) do |next_indent|
+        [
+          channel_element(false, next_indent),
+          image_element(false, next_indent),
+          item_elements(false, next_indent),
+          textinput_element(false, next_indent),
+          other_element(false, next_indent),
+        ]
+      end
       rv = @converter.convert(rv) if convert and @converter
-      remove_empty_newline(rv)
+      rv
     end
 
     private
@@ -119,16 +119,19 @@ EORDF
       end
       
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        <<-EOT
-#{indent}<#{PREFIX}:Seq>
-#{li_elements(convert, next_indent)}
-#{other_element(convert, next_indent)}
-#{indent}</#{PREFIX}:Seq>
-EOT
+        tag(indent) do |next_indent|
+          [
+            li_elements(convert, next_indent),
+            other_element(convert, next_indent),
+          ]
+        end
       end
 
-  		private
+      def full_name
+        tag_name_with_prefix(PREFIX)
+      end
+      
+      private
       def children
         @li
       end
@@ -169,15 +172,15 @@ EOT
         super()
         @resource = resource
       end
+
+      def full_name
+        tag_name_with_prefix(PREFIX)
+      end
       
       def to_s(convert=true, indent=calc_indent)
-        if @resource
-          rv = %Q!#{indent}<#{PREFIX}:li resource="#{h @resource}" />\n!
-          rv = @converter.convert(rv) if convert and @converter
-          rv
-        else
-          ''
-        end
+        rv = tag(indent)
+        rv = @converter.convert(rv) if convert and @converter
+        rv
       end
 
       private
@@ -232,20 +235,17 @@ EOT
       end
 
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        about = ''
-        about << %Q!#{PREFIX}:about="#{h @about}"! if @about
-        rv = <<-EOT
-#{indent}<channel #{about}>
-#{title_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{image_element(false, next_indent)}
-#{items_element(false, next_indent)}
-#{textinput_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</channel>
-EOT
+        rv = tag(indent) do |next_indent|
+          [
+            title_element(false, next_indent),
+            link_element(false, next_indent),
+            description_element(false, next_indent),
+            image_element(false, next_indent),
+            items_element(false, next_indent),
+            textinput_element(false, next_indent),
+            other_element(false, next_indent),
+          ]
+        end
         rv = @converter.convert(rv) if convert and @converter
   	    rv
       end
@@ -270,7 +270,7 @@ EOT
 
       def _attrs
         [
-          ["about", true]
+          ["#{PREFIX}:about", true, "about"]
         ]
       end
       
@@ -298,22 +298,17 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          if @resource
-            rv = %Q!#{indent}<image #{PREFIX}:resource="#{h @resource}" />!
-            rv = @converter.convert(rv) if convert and @converter
-            rv
-          else
-            ''
-          end
+          rv = tag(indent)
+          rv = @converter.convert(rv) if convert and @converter
+          rv
         end
 
         private
         def _attrs
           [
-            ["resource", true]
+            ["#{PREFIX}:resource", true, "resource"]
           ]
         end
-
       end
 
       class Textinput < Element
@@ -340,22 +335,17 @@ EOT
         end
 
         def to_s(convert=true, indent=calc_indent)
-          if @resource
-            rv = %Q|#{indent}<textinput #{PREFIX}:resource="#{h @resource}" />|
-            rv = @converter.convert(rv) if convert and @converter
-            rv
-          else
-            ''
-          end
+          rv = tag(indent)
+          rv = @converter.convert(rv) if convert and @converter
+          rv
         end
         
         private
         def _attrs
           [
-            ["resource", true],
+            ["#{PREFIX}:resource", true, "resource"]
           ]
         end
-
       end
       
       class Items < Element
@@ -387,13 +377,12 @@ EOT
         end
         
         def to_s(convert=true, indent=calc_indent)
-          next_indent = indent + INDENT
-          <<-EOT
-#{indent}<items>
-#{Seq_element(convert, next_indent)}
-#{other_element(convert, next_indent)}
-#{indent}</items>
-EOT
+          rv = tag(indent) do |next_indent|
+            [
+              Seq_element(convert, next_indent),
+              other_element(convert, next_indent),
+            ]
+          end
         end
 
         private
@@ -452,17 +441,14 @@ EOT
       end
 
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        about = ''
-        about << %Q!#{PREFIX}:about="#{h @about}"! if @about
-        rv = <<-EOT
-#{indent}<image #{about}>
-#{title_element(false, next_indent)}
-#{url_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</image>
-EOT
+        rv = tag(indent) do |next_indent|
+          [
+            title_element(false, next_indent),
+            url_element(false, next_indent),
+            link_element(false, next_indent),
+            other_element(false, next_indent),
+          ]
+        end
         rv = @converter.convert(rv) if convert and @converter
         rv
       end
@@ -480,10 +466,9 @@ EOT
 
       def _attrs
         [
-          ["about", true],
+          ["#{PREFIX}:about", true, "about"]
         ]
       end
-
     end
 
     class Item < Element
@@ -522,17 +507,14 @@ EOT
       end
 
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        about = ''
-        about << %Q!#{PREFIX}:about="#{h @about}"! if @about
-        rv = <<-EOT
-#{indent}<item #{about}>
-#{title_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</item>
-EOT
+        rv = tag(indent) do |next_indent|
+          [
+            title_element(false, next_indent),
+            link_element(false, next_indent),
+            description_element(false, next_indent),
+            other_element(false, next_indent),
+          ]
+        end
         rv = @converter.convert(rv) if convert and @converter
         rv
       end
@@ -550,10 +532,9 @@ EOT
 
       def _attrs
         [
-          ["about", true],
+          ["#{PREFIX}:about", true, "about"]
         ]
       end
-
     end
 
     class Textinput < Element
@@ -593,18 +574,15 @@ EOT
       end
 
       def to_s(convert=true, indent=calc_indent)
-        next_indent = indent + INDENT
-        about = ''
-        about << %Q!#{PREFIX}:about="#{h @about}"! if @about
-        rv = <<-EOT
-#{indent}<textinput #{about}>
-#{title_element(false, next_indent)}
-#{description_element(false, next_indent)}
-#{name_element(false, next_indent)}
-#{link_element(false, next_indent)}
-#{other_element(false, next_indent)}
-#{indent}</textinput>
-EOT
+        rv = tag(indent) do |next_indent|
+          [
+            title_element(false, next_indent),
+            description_element(false, next_indent),
+            name_element(false, next_indent),
+            link_element(false, next_indent),
+            other_element(false, next_indent),
+          ]
+        end
         rv = @converter.convert(rv) if convert and @converter
         rv
       end
@@ -623,10 +601,9 @@ EOT
       
       def _attrs
         [
-          ["about", true],
+          ["#{PREFIX}:about", true, "about"]
         ]
       end
-
     end
 
   end
diff --git a/lib/rss/2.0.rb b/lib/rss/2.0.rb
index 7fafb23ba9..0a2d86860d 100644
--- a/lib/rss/2.0.rb
+++ b/lib/rss/2.0.rb
@@ -11,11 +11,18 @@ module RSS
         install_model(x, '?')
       end
 
-      %w(category).each do |x|
-        install_have_child_element(x)
-        install_model(x, '?')
+      undef :ttl=
+      def ttl=(value)
+        @ttl = value.to_i
       end
-
+      
+      [
+        %w(category categories),
+      ].each do |name, plural_name|
+        install_have_children_element(name, plural_name)
+        install_model(name, '*')
+      end
+        
       [
         ["image", "?"],
         ["language", "?"],
@@ -25,7 +32,7 @@ module RSS
 
       def other_element(convert, indent)
         rv = <<-EOT
-#{category_element(convert, indent)}
+#{category_elements(convert, indent)}
 #{generator_element(convert, indent)}
 #{ttl_element(convert, indent)}
 EOT
@@ -35,16 +42,22 @@ EOT
       private
       alias children09 children
       def children
-        children09 + [@category].compact
+        children09 + @category.compact
       end
 
       alias _tags09 _tags
       def _tags
-        %w(generator ttl category).delete_if do |x|
+        rv = %w(generator ttl).delete_if do |x|
           send(x).nil?
         end.collect do |elem|
           [nil, elem]
         end + _tags09
+
+        @category.each do
+          rv << [nil, "category"]
+        end
+        
+        rv
       end
 
       Category = Item::Category
@@ -74,13 +87,15 @@ EOT
         end
       
         def other_element(convert, indent)
-          rv = <<-EOT
-#{author_element(false, indent)}
-#{comments_element(false, indent)}
-#{pubDate_element(false, indent)}
-#{guid_element(false, indent)}
-EOT
-          rv << super
+          rv = [
+            super,
+            *%w(author comments pubDate guid).collect do |name|
+              __send__("#{name}_element", false, indent)
+            end
+          ].reject do |value|
+            /\A\s*\z/.match(value)
+          end
+          rv.join("\n")
         end
 
         private
@@ -116,18 +131,6 @@ EOT
             @content = content
           end
 
-          def to_s(convert=true, indent=calc_indent)
-            if @content
-              rv = %Q!<guid!
-              rv << %Q! isPermaLink="#{h @isPermaLink}"! if @isPermaLink
-              rv << %Q!>#{h @content}</guid>!
-              rv = @converter.convert(rv) if convert and @converter
-              rv
-            else
-              ''
-            end
-          end
-
           private
           def _attrs
             [
diff --git a/lib/rss/maker.rb b/lib/rss/maker.rb
index c158c726c3..66c3bc2928 100644
--- a/lib/rss/maker.rb
+++ b/lib/rss/maker.rb
@@ -7,12 +7,7 @@ module RSS
     MAKERS = {}
     
     class << self
-      def make(version, modules=[], &block)
-        prefix = "rss/maker"
-        require "#{prefix}/#{version}"
-        modules.each do |mod|
-          require "#{prefix}/#{mod}"
-        end
+      def make(version, &block)
         maker(version).make(&block)
       end
 
@@ -31,3 +26,10 @@ module RSS
   end
   
 end
+
+require "rss/maker/1.0"
+require "rss/maker/2.0"
+require "rss/maker/content"
+require "rss/maker/dublincore"
+require "rss/maker/syndication"
+require "rss/maker/trackback"
diff --git a/lib/rss/maker/0.9.rb b/lib/rss/maker/0.9.rb
index 05578082b0..6f26e20f4f 100644
--- a/lib/rss/maker/0.9.rb
+++ b/lib/rss/maker/0.9.rb
@@ -69,9 +69,72 @@ module RSS
           super + ["pubDate"]
         end
 
+        class SkipDays < SkipDaysBase
+          def to_rss(rss, channel)
+            unless @days.empty?
+              skipDays = Rss::Channel::SkipDays.new
+              channel.skipDays = skipDays
+              @days.each do |day|
+                day.to_rss(rss, skipDays.days)
+              end
+            end
+          end
+          
+          class Day < DayBase
+            def to_rss(rss, days)
+              day = Rss::Channel::SkipDays::Day.new
+              set = setup_values(day)
+              if set
+                days << day
+                setup_other_elements(rss)
+              end
+            end
+
+            def have_required_values?
+              @content
+            end
+          end
+        end
+        
+        class SkipHours < SkipHoursBase
+          def to_rss(rss, channel)
+            unless @hours.empty?
+              skipHours = Rss::Channel::SkipHours.new
+              channel.skipHours = skipHours
+              @hours.each do |hour|
+                hour.to_rss(rss, skipHours.hours)
+              end
+            end
+          end
+          
+          class Hour < HourBase
+            def to_rss(rss, hours)
+              hour = Rss::Channel::SkipHours::Hour.new
+              set = setup_values(hour)
+              if set
+                hours << hour
+                setup_other_elements(rss)
+              end
+            end
+
+            def have_required_values?
+              @content
+            end
+          end
+        end
+        
         class Cloud < CloudBase
+          def to_rss(*args)
+          end
         end
 
+        class Categories < CategoriesBase
+          def to_rss(*args)
+          end
+
+          class Category < CategoryBase
+          end
+        end
       end
       
       class Image < ImageBase
@@ -130,9 +193,12 @@ module RSS
             end
           end
         
-          class Category < CategoryBase
+          class Categories < CategoriesBase
             def to_rss(*args)
             end
+
+            class Category < CategoryBase
+            end
           end
           
         end
diff --git a/lib/rss/maker/1.0.rb b/lib/rss/maker/1.0.rb
index 894bcc0a24..ae22eb4fc4 100644
--- a/lib/rss/maker/1.0.rb
+++ b/lib/rss/maker/1.0.rb
@@ -86,7 +86,33 @@ module RSS
           end
         end
 
+        class SkipDays < SkipDaysBase
+          def to_rss(*args)
+          end
+          
+          class Day < DayBase
+          end
+        end
+        
+        class SkipHours < SkipHoursBase
+          def to_rss(*args)
+          end
+
+          class Hour < HourBase
+          end
+        end
+        
         class Cloud < CloudBase
+          def to_rss(*args)
+          end
+        end
+
+        class Categories < CategoriesBase
+          def to_rss(*args)
+          end
+
+          class Category < CategoryBase
+          end
         end
       end
 
@@ -153,9 +179,12 @@ module RSS
             end
           end
         
-          class Category < CategoryBase
+          class Categories < CategoriesBase
             def to_rss(*args)
             end
+
+            class Category < CategoryBase
+            end
           end
         end
       end
diff --git a/lib/rss/maker/2.0.rb b/lib/rss/maker/2.0.rb
index 05fc46480a..8ac5e7bbb3 100644
--- a/lib/rss/maker/2.0.rb
+++ b/lib/rss/maker/2.0.rb
@@ -13,23 +13,26 @@ module RSS
 
       class Channel < RSS09::Channel
 
-        add_other_element("cloud")
-        
         def have_required_values?
           @title and @link and @description
         end
 
-        private
-        def setup_cloud(rss, current)
-          @maker.channel.cloud.to_rss(rss)
+        class SkipDays < RSS09::Channel::SkipDays
+          class Day < RSS09::Channel::SkipDays::Day
+          end
         end
-
+        
+        class SkipHours < RSS09::Channel::SkipHours
+          class Hour < RSS09::Channel::SkipHours::Hour
+          end
+        end
+        
         class Cloud < RSS09::Channel::Cloud
-          def to_rss(rss)
+          def to_rss(rss, channel)
             cloud = Rss::Channel::Cloud.new
             set = setup_values(cloud)
             if set
-              rss.channel.cloud = cloud
+              channel.cloud = cloud
               setup_other_elements(rss)
             end
           end
@@ -39,6 +42,30 @@ module RSS
               @registerProcedure and @protocol
           end
         end
+
+        class Categories < RSS09::Channel::Categories
+          def to_rss(rss, channel)
+            @categories.each do |category|
+              category.to_rss(rss, channel)
+            end
+          end
+          
+          class Category < RSS09::Channel::Categories::Category
+            def to_rss(rss, channel)
+              category = Rss::Channel::Category.new
+              set = setup_values(category)
+              if set
+                channel.category = category
+                setup_other_elements(rss)
+              end
+            end
+            
+            def have_required_values?
+              @content
+            end
+          end
+        end
+        
       end
       
       class Image < RSS09::Image
@@ -102,18 +129,26 @@ module RSS
             end
           end
 
-          class Category < RSS09::Items::Item::Category
+          class Categories < RSS09::Items::Item::Categories
             def to_rss(rss, item)
-              category = Rss::Channel::Item::Category.new
-              set = setup_values(category)
-              if set
-                item.category = category
-                setup_other_elements(rss)
+              @categories.each do |category|
+                category.to_rss(rss, item)
               end
             end
-            
-            def have_required_values?
-              @content
+          
+            class Category < RSS09::Items::Item::Categories::Category
+              def to_rss(rss, item)
+                category = Rss::Channel::Item::Category.new
+                set = setup_values(category)
+                if set
+                  item.category = category
+                  setup_other_elements(rss)
+                end
+              end
+              
+              def have_required_values?
+                @content
+              end
             end
           end
         end
diff --git a/lib/rss/maker/base.rb b/lib/rss/maker/base.rb
index 21222351f2..91eb072ec7 100644
--- a/lib/rss/maker/base.rb
+++ b/lib/rss/maker/base.rb
@@ -38,13 +38,24 @@ module RSS
           OTHER_ELEMENTS
         end
 
-        def self.add_need_initialize_variable(variable_name)
-          const_get("NEED_INITIALIZE_VARIABLES") << variable_name
+        def self.add_need_initialize_variable(variable_name, init_value="nil")
+          const_get("NEED_INITIALIZE_VARIABLES") << [variable_name, init_value]
         end
 
         def self.need_initialize_variables
           NEED_INITIALIZE_VARIABLES
         end
+
+        def self.def_array_element(name)
+          include Enumerable
+          extend Forwardable
+
+          def_delegators("@\#{name}", :<<, :[], :[]=, :first, :last)
+          def_delegators("@\#{name}", :push, :pop, :shift, :unshift)
+          def_delegators("@\#{name}", :each)
+          
+          add_need_initialize_variable(name, "[]")
+        end
         EOC
       end
       
@@ -59,8 +70,8 @@ module RSS
       
       private
       def initialize_variables
-        self.class.need_initialize_variables.each do |variable_name|
-          instance_eval("@#{variable_name} = nil", __FILE__, __LINE__)
+        self.class.need_initialize_variables.each do |variable_name, init_value|
+          instance_eval("@#{variable_name} = #{init_value}", __FILE__, __LINE__)
         end
       end
 
@@ -88,7 +99,11 @@ module RSS
       end
 
       def variables
-        self.class.need_initialize_variables
+        self.class.need_initialize_variables.find_all do |name, init|
+          "nil" == init
+        end.collect do |name, init|
+          name
+        end
       end
       
     end
@@ -159,17 +174,7 @@ module RSS
     class XMLStyleSheets
       include Base
 
-      include Enumerable
-      extend Forwardable
-
-      def_delegators(:@xml_stylesheets, :<<, :[], :[]=, :first, :last)
-      def_delegators(:@xml_stylesheets, :push, :pop, :shift, :unshift)
-      def_delegators(:@xml_stylesheets, :each)
-
-      def initialize(maker)
-        super
-        @xml_stylesheets = []
-      end
+      def_array_element("xml_stylesheets")
 
       def to_rss(rss)
         @xml_stylesheets.each do |xss|
@@ -217,12 +222,25 @@ module RSS
     class ChannelBase
       include Base
 
-      attr_reader :cloud
+      %w(cloud categories skipDays skipHours).each do |element|
+        attr_reader element
+        add_other_element(element)
+        add_need_initialize_variable(element, "make_#{element}")
+        module_eval(<<-EOC, __FILE__, __LINE__)
+          private
+          def setup_#{element}(rss, current)
+            @#{element}.to_rss(rss, current)
+          end
+
+          def make_#{element}
+            self.class::#{element[0,1].upcase}#{element[1..-1]}.new(@maker)
+          end
+EOC
+      end
 
       %w(about title link description language copyright
-      managingEditor webMaster rating docs skipDays
-      skipHours date lastBuildDate category generator ttl
-      ).each do |element|
+         managingEditor webMaster rating docs date
+         lastBuildDate generator ttl).each do |element|
         attr_accessor element
         add_need_initialize_variable(element)
       end
@@ -230,18 +248,68 @@ module RSS
       alias_method(:pubDate, :date)
       alias_method(:pubDate=, :date=)
 
-      def initialize(maker)
-        super
-        @cloud = make_cloud
-      end
-
       def current_element(rss)
         rss.channel
       end
 
-      private
-      def make_cloud
-        self.class::Cloud.new(@maker)
+      class SkipDaysBase
+        include Base
+
+        def_array_element("days")
+
+        def new_day
+          day = self.class::Day.new(@maker)
+          @days << day 
+          day
+        end
+        
+        def current_element(rss)
+          rss.channel.skipDays
+        end
+
+        class DayBase
+          include Base
+          
+          %w(content).each do |element|
+            attr_accessor element
+            add_need_initialize_variable(element)
+          end
+
+          def current_element(rss)
+            rss.channel.skipDays.last
+          end
+
+        end
+      end
+      
+      class SkipHoursBase
+        include Base
+
+        def_array_element("hours")
+
+        def new_hour
+          hour = self.class::Hour.new(@maker)
+          @hours << hour 
+          hour
+        end
+        
+        def current_element(rss)
+          rss.channel.skipHours
+        end
+
+        class HourBase
+          include Base
+          
+          %w(content).each do |element|
+            attr_accessor element
+            add_need_initialize_variable(element)
+          end
+
+          def current_element(rss)
+            rss.channel.skipHours.last
+          end
+
+        end
       end
       
       class CloudBase
@@ -257,6 +325,27 @@ module RSS
         end
 
       end
+
+      class CategoriesBase
+        include Base
+        
+        def_array_element("categories")
+
+        def new_category
+          category = self.class::Category.new(@maker)
+          @categories << category
+          category
+        end
+
+        class CategoryBase
+          include Base
+
+          %w(domain content).each do |element|
+            attr_accessor element
+            add_need_initialize_variable(element)
+          end
+        end
+      end
     end
     
     class ImageBase
@@ -279,18 +368,12 @@ module RSS
     class ItemsBase
       include Base
 
-      include Enumerable
-      extend Forwardable
-
-      def_delegators(:@items, :<<, :[], :[]=, :first, :last)
-      def_delegators(:@items, :push, :pop, :shift, :unshift)
-      def_delegators(:@items, :each)
+      def_array_element("items")
       
       attr_accessor :do_sort
       
       def initialize(maker)
         super
-        @items = []
         @do_sort = false
       end
       
@@ -326,9 +409,10 @@ module RSS
       class ItemBase
         include Base
         
-        %w(guid enclosure source category).each do |element|
+        %w(guid enclosure source categories).each do |element|
           attr_reader element
           add_other_element(element)
+          add_need_initialize_variable(element, "make_#{element}")
           module_eval(<<-EOC, __FILE__, __LINE__)
           private
           def setup_#{element}(rss, current)
@@ -349,14 +433,6 @@ EOC
         alias_method(:pubDate, :date)
         alias_method(:pubDate=, :date=)
 
-        def initialize(maker)
-          super
-          @guid = make_guid
-          @enclosure = make_enclosure
-          @source = make_source
-          @category = make_category
-        end
-      
         def <=>(other)
           if @date and other.date
             @date <=> other.date
@@ -400,14 +476,7 @@ EOC
           end
         end
       
-        class CategoryBase
-          include Base
-
-          %w(domain content).each do |element|
-            attr_accessor element
-            add_need_initialize_variable(element)
-          end
-        end
+        CategoriesBase = ChannelBase::CategoriesBase
       
       end
     end
diff --git a/lib/rss/maker/trackback.rb b/lib/rss/maker/trackback.rb
index 1ec59ab0b0..ef78bf2f20 100644
--- a/lib/rss/maker/trackback.rb
+++ b/lib/rss/maker/trackback.rb
@@ -1,5 +1,6 @@
 require 'rss/trackback'
 require 'rss/maker/1.0'
+require 'rss/maker/2.0'
 
 module RSS
   module Maker
@@ -7,18 +8,65 @@ module RSS
       def self.append_features(klass)
         super
 
-        %w(ping about).each do |element|
-          name = "#{RSS::TRACKBACK_PREFIX}_#{element}"
-          klass.add_need_initialize_variable(name)
-          klass.add_other_element(name)
-          klass.__send__(:attr_accessor, name)
-          klass.module_eval(<<-EOC, __FILE__, __LINE__)
-            def setup_#{name}(rss, current)
-              if #{name} and current.respond_to?(:#{name}=)
-                current.#{name} = @#{name} if @#{name}
-              end
+        name = "#{RSS::TRACKBACK_PREFIX}_ping"
+        klass.add_need_initialize_variable(name)
+        klass.add_other_element(name)
+        klass.__send__(:attr_accessor, name)
+        klass.module_eval(<<-EOC, __FILE__, __LINE__)
+          def setup_#{name}(rss, current)
+            if #{name} and current.respond_to?(:#{name}=)
+              current.#{name} = #{name}
             end
-          EOC
+          end
+        EOC
+
+        name = "#{RSS::TRACKBACK_PREFIX}_abouts"
+        klass.add_need_initialize_variable(name, "make_#{name}")
+        klass.add_other_element(name)
+        klass.__send__(:attr_accessor, name)
+        klass.module_eval(<<-EOC, __FILE__, __LINE__)
+          def make_#{name}
+            self.class::TrackBackAbouts.new(self)
+          end
+
+          def setup_#{name}(rss, current)
+            @#{name}.to_rss(rss, current)
+          end
+        EOC
+      end
+
+      class TrackBackAboutsBase
+        include Base
+
+        def_array_element("abouts")
+        
+        def new_about
+          about = self.class::About.new(@maker)
+          @abouts << about 
+          about
+        end
+
+        def to_rss(rss, current)
+          @abouts.each do |about|
+            about.to_rss(rss, current)
+          end
+        end
+        
+        class AboutBase
+          include Base
+
+          attr_accessor :value
+          add_need_initialize_variable(:value)
+          
+          alias_method(:resource, :value)
+          alias_method(:resource=, :value=)
+          alias_method(:content, :value)
+          alias_method(:content=, :value=)
+        
+          def have_required_values?
+            @value
+          end
+          
         end
       end
     end
@@ -26,5 +74,53 @@ module RSS
     class ItemsBase
       class ItemBase; include TrackBackModel; end
     end
+
+    class RSS10
+      class Items
+        class Item
+          class TrackBackAbouts < TrackBackAboutsBase
+            class About < AboutBase
+              def to_rss(rss, current)
+                if resource
+                  about = ::RSS::TrackBackModel10::About.new(resource)
+                  current.trackback_abouts << about
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+
+    class RSS09
+      class Items
+        class Item
+          class TrackBackAbouts < TrackBackAboutsBase
+            def to_rss(*args)
+            end
+            class About < AboutBase
+            end
+          end
+        end
+      end
+    end
+    
+    class RSS20
+      class Items
+        class Item
+          class TrackBackAbouts < TrackBackAboutsBase
+            class About < AboutBase
+              def to_rss(rss, current)
+                if content
+                  about = ::RSS::TrackBackModel20::About.new(content)
+                  current.trackback_abouts << about
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+    
   end
 end
diff --git a/lib/rss/parser.rb b/lib/rss/parser.rb
index 09b3213372..e1da24418a 100644
--- a/lib/rss/parser.rb
+++ b/lib/rss/parser.rb
@@ -348,6 +348,13 @@ module RSS
         end
 
         if @do_validate and required and val.nil?
+          unless a_uri.include?(nil)
+            for prefix, uri in ns
+              if a_uri.include?(uri)
+                a_name = "#{prefix}:#{a_name}"
+              end
+            end
+          end
           raise MissingAttributeError.new(tag_name, a_name)
         end
 
diff --git a/lib/rss/rexmlparser.rb b/lib/rss/rexmlparser.rb
index 375b7794fb..73e352a731 100644
--- a/lib/rss/rexmlparser.rb
+++ b/lib/rss/rexmlparser.rb
@@ -36,7 +36,7 @@ module RSS
     include ListenerMixin
 
     def xmldecl(version, encoding, standalone)
-      super
+      super(version, encoding, standalone == "yes")
       # Encoding is converted to UTF-8 when REXML parse XML.
       @encoding = 'UTF-8'
     end
diff --git a/lib/rss/rss.rb b/lib/rss/rss.rb
index b6afa24b93..a63bee8a69 100644
--- a/lib/rss/rss.rb
+++ b/lib/rss/rss.rb
@@ -58,7 +58,7 @@ require "rss/xml-stylesheet"
 
 module RSS
 
-  VERSION = "0.1.0"
+  VERSION = "0.1.1"
 
   URI = "http://purl.org/rss/1.0/"
 
@@ -164,17 +164,17 @@ EOC
     end
     alias_method(:install_have_attribute_element, :install_have_child_element)
 
-    def install_have_children_element(name, postfix="s")
+    def install_have_children_element(name, plural_name=nil)
       add_have_children_element(name)
 
-      def_children_accessor(name, postfix)
-      install_element(name, postfix) do |n, elem_name|
+      def_children_accessor(name, plural_name)
+      install_element(name, "s") do |n, elem_name|
         <<-EOC
-        rv = ''
+        rv = []
         @#{n}.each do |x|
           rv << "\#{x.to_s(convert, indent)}"
         end
-        rv
+        rv.join("\n")
 EOC
       end
     end
@@ -289,9 +289,10 @@ EOC
       end
     end
 
-    def def_children_accessor(accessor_name, postfix="s")
+    def def_children_accessor(accessor_name, plural_name=nil)
+      plural_name ||= "#{accessor_name}s"
       module_eval(<<-EOC, *get_file_and_line_from_caller(2))
-      def #{accessor_name}#{postfix}
+      def #{plural_name}
         @#{accessor_name}
       end
 
@@ -314,6 +315,22 @@ EOC
 EOC
     end
 
+    def def_content_only_to_s
+      module_eval(<<-EOC, *get_file_and_line_from_caller(2))
+      def to_s(convert=true, indent=calc_indent)
+        if @content
+          rv = tag(indent) do |next_indent|
+            h(@content)
+          end
+          rv = @converter.convert(rv) if convert and @converter
+          rv
+        else
+          ""
+        end
+      end
+EOC
+    end
+    
   end
 
   class Element
@@ -329,7 +346,8 @@ EOC
         klass.module_eval(<<-EOC)
         public
         
-        @tag_name = name.split(/::/).last.downcase
+        @tag_name = name.split(/::/).last
+        @tag_name[0,1] = @tag_name[0,1].downcase
         @indent_size = name.split(/::/).size - 2
 
         @@must_call_validators = {}
@@ -373,6 +391,7 @@ EOC
         def self.content_setup
           attr_writer :content
           convert_attr_reader :content
+          def_content_only_to_s
           @@have_content = true
         end
 
@@ -440,6 +459,14 @@ EOC
       self.class.tag_name
     end
 
+    def full_name
+      tag_name
+    end
+    
+    def indent_size
+      self.class.indent_size
+    end
+    
     def converter=(converter)
       @converter = converter
       children.each do |child|
@@ -472,6 +499,66 @@ EOC
       end
     end
 
+    def tag(indent, additional_attrs=[])
+      next_indent = indent + INDENT
+
+      attrs = collect_attrs
+      return "" if attrs.nil?
+
+      attrs += additional_attrs
+      start_tag = make_start_tag(indent, next_indent, attrs)
+      
+      if block_given?
+        content = yield(next_indent)
+      else
+        content = []
+      end
+
+      if content.is_a?(String)
+        content = [content]
+        start_tag << ">"
+        end_tag = "</#{full_name}>"
+      else
+        content = content.reject{|x| x.empty?}
+        if content.empty?
+          end_tag = "/>"
+        else
+          start_tag << ">\n"
+          end_tag = "\n#{indent}</#{full_name}>"
+        end
+      end
+      
+      start_tag + content.join("\n") + end_tag
+    end
+
+    def make_start_tag(indent, next_indent, attrs)
+      start_tag = ["#{indent}<#{full_name}"]
+      unless attrs.empty?
+        start_tag << attrs.collect do |key, value|
+          %Q[#{h key}="#{h value}"]
+        end.join("\n#{next_indent}")
+      end
+      start_tag.join(" ")
+    end
+
+    def collect_attrs
+      _attrs.collect do |name, required, alias_name|
+        value = __send__(alias_name || name)
+        return nil if required and value.nil?
+        [name, value]
+      end.reject do |name, value|
+        value.nil?
+      end
+    end
+    
+    def tag_name_with_prefix(prefix)
+      "#{prefix}:#{tag_name}"
+    end
+    
+    def calc_indent
+      INDENT * (self.class.indent_size)
+    end
+    
     # not String class children.
     def children
       []
@@ -507,23 +594,23 @@ EOC
     end
 
     def validate_attribute
-      _attrs.each do |a_name, required|
-        if required and send(a_name).nil?
-          raise MissingAttributeError.new(self.class.tag_name, a_name)
+      _attrs.each do |a_name, required, alias_name|
+        if required and __send__(alias_name || a_name).nil?
+          raise MissingAttributeError.new(tag_name, a_name)
         end
       end
     end
 
     def other_element(convert, indent='')
-      rv = ''
+      rv = []
       private_methods.each do |meth|
         if /\A([^_]+)_[^_]+_elements?\z/ =~ meth and
             self.class::NSPOOL.has_key?($1)
-          res = send(meth, convert)
-          rv << "#{indent}#{res}\n" if /\A\s*\z/ !~ res
+          res = __send__(meth, convert)
+          rv << "#{indent}#{res}" if /\A\s*\z/ !~ res
         end
       end
-      rv
+      rv.join("\n")
     end
 
     def _validate(tags, model=self.class.model)
@@ -626,19 +713,12 @@ EOC
       rv
     end
 
-    private
-    def calc_indent
-      INDENT * (self.class.indent_size)
-    end
-    
-    def remove_empty_newline(string)
-      string.gsub(/^\s*$(?:\r?\n?)/, '')
-    end
-    
   end
 
   module RootElementMixin
 
+    include XMLStyleSheetMixin
+    
     attr_reader :output_encoding
 
     def initialize(rss_version, version=nil, encoding=nil, standalone=nil)
@@ -656,23 +736,27 @@ EOC
     end
 
     private
+    def tag(indent, attrs)
+      rv = xmldecl + xml_stylesheet_pi
+      rv << super
+      rv
+    end
+
     def xmldecl
       rv = %Q[<?xml version="#{@version}"]
       if @output_encoding or @encoding
         rv << %Q[ encoding="#{@output_encoding or @encoding}"]
       end
-      rv << %Q[ standalone="#{@standalone}"] if @standalone
-      rv << '?>'
+      rv << %Q[ standalone="yes"] if @standalone
+      rv << "?>\n"
       rv
     end
     
-    def ns_declaration(indent)
-      rv = ''
-      self.class::NSPOOL.each do |prefix, uri|
+    def ns_declarations
+      self.class::NSPOOL.collect do |prefix, uri|
         prefix = ":#{prefix}" unless prefix.empty?
-        rv << %Q|\n#{indent}xmlns#{prefix}="#{html_escape(uri)}"|
+        ["xmlns#{prefix}", uri]
       end
-      rv
     end
     
   end
diff --git a/lib/rss/trackback.rb b/lib/rss/trackback.rb
index e276305ec1..5cbf652406 100644
--- a/lib/rss/trackback.rb
+++ b/lib/rss/trackback.rb
@@ -9,7 +9,16 @@ module RSS
   RDF.install_ns(TRACKBACK_PREFIX, TRACKBACK_URI)
   Rss.install_ns(TRACKBACK_PREFIX, TRACKBACK_URI)
 
-  module BaseTrackBackModel
+  module TrackBackUtils
+    private
+    def new_with_value_if_need(klass, value)
+      if value.is_a?(klass)
+        value
+      else
+        klass.new(value)
+      end
+    end
+          
     def trackback_validate(tags)
       counter = {}
       %w(ping about).each do |x|
@@ -31,179 +40,64 @@ module RSS
       end
     end
   end
-
-  module TrackBackModel10
-    extend BaseModel
-    include BaseTrackBackModel
-
-    def self.append_features(klass)
+  
+  module BaseTrackBackModel
+    def append_features(klass)
       super
 
       unless klass.class == Module
-        %w(ping).each do |x|
-          klass.install_have_child_element("#{TRACKBACK_PREFIX}_#{x}")
-        end
-        
-        %w(about).each do |x|
-          klass.install_have_children_element("#{TRACKBACK_PREFIX}_#{x}")
-        end
-      end
-    end
+        klass.__send__(:include, TrackBackUtils)
 
-    class Ping < Element
-      include RSS10
-
-      class << self
-
-        def required_prefix
-          TRACKBACK_PREFIX
-        end
-        
-        def required_uri
-          TRACKBACK_URI
-        end
-
-      end
-      
-      [
-        ["resource", ::RSS::RDF::URI, true]
-      ].each do |name, uri, required|
-        install_get_attribute(name, uri, required)
-      end
-
-      def initialize(resource=nil)
-        super()
-        @resource = resource
-      end
-
-      def to_s(convert=true, indent=calc_indent)
-        if @resource
-          rv = %Q[#{indent}<#{TRACKBACK_PREFIX}:ping ]
-          rv << %Q[#{::RSS::RDF::PREFIX}:resource="#{h @resource}"/>]
-          rv = @converter.convert(rv) if convert and @converter
-          rv
-        else
-          ''
-        end
-      end
-
-      private
-      def _attrs
-        [
-          ["resource", true],
-        ]
-      end
-
-    end
-
-    class About < Element
-      include RSS10
-
-      class << self
-        
-        def required_prefix
-          TRACKBACK_PREFIX
-        end
-        
-        def required_uri
-          TRACKBACK_URI
-        end
-
-      end
-      
-      [
-        ["resource", ::RSS::RDF::URI, true]
-      ].each do |name, uri, required|
-        install_get_attribute(name, uri, required)
-      end
-
-      def initialize(resource=nil)
-        super()
-        @resource = resource
-      end
-
-      def to_s(convert=true, indent=calc_indent)
-        if @resource
-          rv = %Q[#{indent}<#{TRACKBACK_PREFIX}:about ]
-          rv << %Q[#{::RSS::RDF::PREFIX}:resource="#{h @resource}"/>]
-          rv = @converter.convert(rv) if convert and @converter
-          rv
-        else
-          ''
-        end
-      end
-
-      private
-      def _attrs
-        [
-          ["resource", true],
-        ]
-      end
-
-    end
-  end
-
-  module TrackBackModel20
-    include BaseTrackBackModel
-    extend BaseModel
-
-    def self.append_features(klass)
-      super
-
-      unless klass.class == Module
         %w(ping).each do |x|
           var_name = "#{TRACKBACK_PREFIX}_#{x}"
+          klass_name = x.capitalize
           klass.install_have_child_element(var_name)
-          klass.module_eval(<<-EOC)
-            alias _#{var_name} #{var_name}
+          klass.module_eval(<<-EOC, __FILE__, __LINE__)
+            undef #{var_name}
             def #{var_name}
-              @#{var_name} and @#{var_name}.content
+              @#{var_name} and @#{var_name}.value
             end
 
-            alias _#{var_name}= #{var_name}=
-            def #{var_name}=(content)
-              @#{var_name} = new_with_content_if_need(#{x.capitalize}, content)
+            undef #{var_name}=
+            def #{var_name}=(value)
+              @#{var_name} = new_with_value_if_need(#{klass_name}, value)
             end
           EOC
         end
         
         [%w(about s)].each do |x, postfix|
           var_name = "#{TRACKBACK_PREFIX}_#{x}"
+          klass_name = x.capitalize
           klass.install_have_children_element(var_name)
-          klass.module_eval(<<-EOC)
-            alias _#{var_name}#{postfix} #{var_name}#{postfix}
-            def #{var_name}#{postfix}
-              @#{var_name}.collect {|x| x.content}
-            end
-
-            alias _#{var_name} #{var_name}
+          klass.module_eval(<<-EOC, __FILE__, __LINE__)
+            undef #{var_name}
             def #{var_name}(*args)
               if args.empty?
-                @#{var_name}.first and @#{var_name}.first.content
+                @#{var_name}.first and @#{var_name}.first.value
               else
                 ret = @#{var_name}.send("[]", *args)
                 if ret.is_a?(Array)
-                  ret.collect {|x| x.content}
+                  ret.collect {|x| x.value}
                 else
-                  ret.content
+                  ret.value
                 end
               end
             end
 
-            alias _#{var_name}= #{var_name}=
-            alias _set_#{var_name} set_#{var_name}
+            undef #{var_name}=
+            undef set_#{var_name}
             def #{var_name}=(*args)
               if args.size == 1
-                item = new_with_content_if_need(#{x.capitalize}, args[0])
+                item = new_with_value_if_need(#{klass_name}, args[0])
                 @#{var_name}.push(item)
               else
                 new_val = args.last
                 if new_val.is_a?(Array)
                   new_val = new_value.collect do |val|
-                    new_with_content_if_need(#{x.capitalize}, val)
+                    new_with_value_if_need(#{klass_name}, val)
                   end
                 else
-                  new_val = new_with_content_if_need(#{x.capitalize}, new_val)
+                  new_val = new_with_value_if_need(#{klass_name}, new_val)
                 end
                 @#{var_name}.send("[]=", *(args[0..-2] + [new_val]))
               end
@@ -213,22 +107,112 @@ module RSS
         end
       end
     end
+  end
 
-    private
-    def new_with_content(klass, content)
-      obj = klass.new
-      obj.content = content
-      obj
-    end
+  module TrackBackModel10
+    extend BaseModel
+    extend BaseTrackBackModel
+
+    class Ping < Element
+      include RSS10
+
+      class << self
+
+        def required_prefix
+          TRACKBACK_PREFIX
+        end
+        
+        def required_uri
+          TRACKBACK_URI
+        end
 
-    def new_with_content_if_need(klass, content)
-      if content.is_a?(klass)
-        content
-      else
-        new_with_content(klass, content)
       end
+      
+      [
+        ["resource", ::RSS::RDF::URI, true]
+      ].each do |name, uri, required|
+        install_get_attribute(name, uri, required)
+      end
+
+      alias_method(:value, :resource)
+      alias_method(:value=, :resource=)
+      
+      def initialize(resource=nil)
+        super()
+        @resource = resource
+      end
+
+      def full_name
+        tag_name_with_prefix(TRACKBACK_PREFIX)
+      end
+      
+      def to_s(convert=true, indent=calc_indent)
+        rv = tag(indent)
+        rv = @converter.convert(rv) if convert and @converter
+        rv
+      end
+
+      private
+      def _attrs
+        [
+          ["#{::RSS::RDF::PREFIX}:resource", true, "resource"],
+        ]
+      end
+
     end
 
+    class About < Element
+      include RSS10
+
+      class << self
+        
+        def required_prefix
+          TRACKBACK_PREFIX
+        end
+        
+        def required_uri
+          TRACKBACK_URI
+        end
+
+      end
+      
+      [
+        ["resource", ::RSS::RDF::URI, true]
+      ].each do |name, uri, required|
+        install_get_attribute(name, uri, required)
+      end
+
+      alias_method(:value, :resource)
+      alias_method(:value=, :resource=)
+      
+      def initialize(resource=nil)
+        super()
+        @resource = resource
+      end
+
+      def full_name
+        tag_name_with_prefix(TRACKBACK_PREFIX)
+      end
+      
+      def to_s(convert=true, indent=calc_indent)
+        rv = tag(indent)
+        rv = @converter.convert(rv) if convert and @converter
+        rv
+      end
+
+      private
+      def _attrs
+        [
+          ["#{::RSS::RDF::PREFIX}:resource", true, "resource"],
+        ]
+      end
+
+    end
+  end
+
+  module TrackBackModel20
+    extend BaseModel
+    extend BaseTrackBackModel
 
     class Ping < Element
       include RSS09
@@ -247,18 +231,18 @@ module RSS
 
       end
       
-      def to_s(convert=true, indent=calc_indent)
-        if @content
-          rv = %Q[#{indent}<#{TRACKBACK_PREFIX}:ping>]
-          rv << h(@content)
-          rv << %Q[</#{TRACKBACK_PREFIX}:ping>]
-          rv = @converter.convert(rv) if convert and @converter
-          rv
-        else
-          ''
-        end
-      end
+      alias_method(:value, :content)
+      alias_method(:value=, :content=)
 
+      def initialize(content=nil)
+        super()
+        @content = content
+      end
+      
+      def full_name
+        tag_name_with_prefix(TRACKBACK_PREFIX)
+      end
+      
     end
 
     class About < Element
@@ -277,19 +261,19 @@ module RSS
         end
 
       end
-      
-      def to_s(convert=true, indent=calc_indent)
-        if @content
-          rv = %Q[#{indent}<#{TRACKBACK_PREFIX}:about>]
-          rv << h(@content)
-          rv << %Q[</#{TRACKBACK_PREFIX}:about>]
-          rv = @converter.convert(rv) if convert and @converter
-          rv
-        else
-          ''
-        end
-      end
 
+      alias_method(:value, :content)
+      alias_method(:value=, :content=)
+
+      def initialize(content=nil)
+        super()
+        @content = content
+      end
+      
+      def full_name
+        tag_name_with_prefix(TRACKBACK_PREFIX)
+      end
+      
     end
   end
 
diff --git a/lib/rss/xmlscanner.rb b/lib/rss/xmlscanner.rb
index 472ca93523..c5a11bad18 100644
--- a/lib/rss/xmlscanner.rb
+++ b/lib/rss/xmlscanner.rb
@@ -45,7 +45,7 @@ module RSS
     end
 
     def on_xmldecl_end
-      xmldecl(@version, @encoding, @standalone)
+      xmldecl(@version, @encoding, @standalone == "yes")
     end
 
     alias_method(:on_pi, :instruction)
diff --git a/test/rss/rss-assertions.rb b/test/rss/rss-assertions.rb
index 6b83cbe093..a51fc1fd60 100644
--- a/test/rss/rss-assertions.rb
+++ b/test/rss/rss-assertions.rb
@@ -94,27 +94,32 @@ module RSS
         end
       end
     end
-    
-    def assert_xml_stylesheet_attrs(xsl, attrs)
+
+    def assert_xml_declaration(version, encoding, standalone, rss)
       _wrap_assertion do
-        normalized_attrs = {}
-        attrs.each do |name, value|
-          normalized_attrs[name.to_s] = value
-        end
+        assert_equal(version, rss.version)
+        assert_equal(encoding, rss.encoding)
+        assert_equal(standalone, rss.standalone)
+      end
+    end
+    
+    def assert_xml_stylesheet_attrs(attrs, xsl)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
         ::RSS::XMLStyleSheet::ATTRIBUTES.each do |name|
-          assert_equal(normalized_attrs[name], xsl.send(name))
+          assert_equal(n_attrs[name], xsl.send(name))
         end
       end
     end
     
-    def assert_xml_stylesheet(target, xsl, attrs)
+    def assert_xml_stylesheet(target, attrs, xsl)
       _wrap_assertion do
         if attrs.has_key?(:href)
           if !attrs.has_key?(:type) and attrs.has_key?(:guess_type)
             attrs[:type] = attrs[:guess_type]
           end
           assert_equal("xml-stylesheet", target)
-          assert_xml_stylesheet_attrs(xsl, attrs)
+          assert_xml_stylesheet_attrs(attrs, xsl)
         else
           assert_nil(target)
           assert_equal("", xsl.to_s)
@@ -123,40 +128,314 @@ module RSS
     end
     
     def assert_xml_stylesheet_pis(attrs_ary)
-      rdf = ::RSS::RDF.new()
-      xss_strs = []
-      attrs_ary.each do |attrs|
-        xss = ::RSS::XMLStyleSheet.new(*attrs)
-        xss_strs.push(xss.to_s)
-        rdf.xml_stylesheets.push(xss)
+      _wrap_assertion do
+        rdf = ::RSS::RDF.new()
+        xss_strs = []
+        attrs_ary.each do |attrs|
+          xss = ::RSS::XMLStyleSheet.new(*attrs)
+          xss_strs.push(xss.to_s)
+          rdf.xml_stylesheets.push(xss)
+        end
+        pi_str = rdf.to_s.gsub(/<\?xml .*\n/, "").gsub(/\s*<rdf:RDF.*\z/m, "")
+        assert_equal(xss_strs.join("\n"), pi_str)
       end
-      pi_str = rdf.to_s.gsub(/<\?xml .*\n/, "").gsub(/\s*<rdf:RDF.*\z/m, "")
-      assert_equal(xss_strs.join("\n"), pi_str)
     end
 
+    def assert_xml_stylesheets(attrs, xss)
+      _wrap_assertion do
+        xss.each_with_index do |xs, i|
+          assert_xml_stylesheet_attrs(attrs[i], xs)
+        end
+      end
+    end
+
+    
+    def assert_channel10(attrs, channel)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
+        
+        names = %w(about title link description)
+        assert_attributes(attrs, names, channel)
+
+        %w(image items textinput).each do |name|
+          value = n_attrs[name]
+          if value
+            target = channel.__send__(name)
+            __send__("assert_channel10_#{name}", value, target)
+          end
+        end
+      end
+    end
+
+    def assert_channel10_image(attrs, image)
+      _wrap_assertion do
+        assert_attributes(attrs, %w(resource), image)
+      end
+    end
+    
+    def assert_channel10_textinput(attrs, textinput)
+      _wrap_assertion do
+        assert_attributes(attrs, %w(resource), textinput)
+      end
+    end
+
+    def assert_channel10_items(attrs, items)
+      _wrap_assertion do
+        items.Seq.lis.each_with_index do |li, i|
+          assert_attributes(attrs[i], %w(resource), li)
+        end
+      end
+    end
+
+    def assert_image10(attrs, image)
+      _wrap_assertion do
+        names = %w(about title url link)
+        assert_attributes(attrs, names, image)
+      end
+    end
+
+    def assert_items10(attrs, items)
+      _wrap_assertion do
+        names = %w(about title link description)
+        items.each_with_index do |item, i|
+          assert_attributes(attrs[i], names, item)
+        end
+      end
+    end
+
+    def assert_textinput10(attrs, textinput)
+      _wrap_assertion do
+        names = %w(about title description name link)
+        assert_attributes(attrs, names, textinput)
+      end
+    end
+
+
+    def assert_channel09(attrs, channel)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
+
+        names = %w(title description link language rating
+                   copyright pubDate lastBuildDate docs
+                   managingEditor webMaster)
+        assert_attributes(attrs, names, channel)
+        
+        %w(skipHours skipDays).each do |name|
+          value = n_attrs[name]
+          if value
+            target = channel.__send__(name)
+            __send__("assert_channel09_#{name}", value, target)
+          end
+        end
+      end
+    end
+
+    def assert_channel09_skipDays(contents, skipDays)
+      _wrap_assertion do
+        days = skipDays.days
+        contents.each_with_index do |content, i|
+          assert_equal(content, days[i].content)
+        end
+      end
+    end
+    
+    def assert_channel09_skipHours(contents, skipHours)
+      _wrap_assertion do
+        hours = skipHours.hours
+        contents.each_with_index do |content, i|
+          assert_equal(content, hours[i].content)
+        end
+      end
+    end
+    
+    def assert_image09(attrs, image)
+      _wrap_assertion do
+        names = %w(url link title description width height)
+        assert_attributes(attrs, names, image)
+      end
+    end
+
+    def assert_items09(attrs, items)
+      _wrap_assertion do
+        names = %w(title link description)
+        items.each_with_index do |item, i|
+          assert_attributes(attrs[i], names, item)
+        end
+      end
+    end
+    
+    def assert_textinput09(attrs, textinput)
+      _wrap_assertion do
+        names = %w(title description name link)
+        assert_attributes(attrs, names, textinput)
+      end
+    end
+
+
+    def assert_channel20(attrs, channel)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
+        
+        names = %w(title link description language copyright
+                   managingEditor webMaster pubDate
+                   lastBuildDate generator docs ttl rating)
+        assert_attributes(attrs, names, channel)
+
+        %w(cloud categories skipHours skipDays).each do |name|
+          value = n_attrs[name]
+          if value
+            target = channel.__send__(name)
+            __send__("assert_channel20_#{name}", value, target)
+          end
+        end
+      end
+    end
+
+    def assert_channel20_skipDays(contents, skipDays)
+      assert_channel09_skipDays(contents, skipDays)
+    end
+    
+    def assert_channel20_skipHours(contents, skipHours)
+      assert_channel09_skipHours(contents, skipHours)
+    end
+    
+    def assert_channel20_cloud(attrs, cloud)
+      _wrap_assertion do
+        names = %w(domain port path registerProcedure protocol)
+        assert_attributes(attrs, names, cloud)
+      end
+    end
+    
+    def assert_channel20_categories(attrs, categories)
+      _wrap_assertion do
+        names = %w(domain content)
+        categories.each_with_index do |category, i|
+          assert_attributes(attrs[i], names, category)
+        end
+      end
+    end
+    
+    def assert_image20(attrs, image)
+      _wrap_assertion do
+        names = %w(url link title description width height)
+        assert_attributes(attrs, names, image)
+      end
+    end
+
+    def assert_items20(attrs, items)
+      _wrap_assertion do
+        names = %w(about title link description)
+        items.each_with_index do |item, i|
+          assert_attributes(attrs[i], names, item)
+
+          n_attrs = normalized_attrs(attrs[i])
+
+          %w(source enclosure categories guid).each do |name|
+            value = n_attrs[name]
+            if value
+              target = item.__send__(name)
+              __send__("assert_items20_#{name}", value, target)
+            end
+          end
+        end
+      end
+    end
+
+    def assert_items20_source(attrs, source)
+      _wrap_assertion do
+        assert_attributes(attrs, %w(url content), source)
+      end
+    end
+    
+    def assert_items20_enclosure(attrs, enclosure)
+      _wrap_assertion do
+        names = %w(url length type)
+        assert_attributes(attrs, names, enclosure)
+      end
+    end
+    
+    def assert_items20_categories(attrs, categories)
+      _wrap_assertion do
+        assert_channel20_categories(attrs, categories)
+      end
+    end
+    
+    def assert_items20_guid(attrs, guid)
+      _wrap_assertion do
+        assert_attributes(attrs, %w(isPermaLink content), guid)
+      end
+    end
+
+    def assert_textinput20(attrs, textinput)
+      _wrap_assertion do
+        names = %w(title description name link)
+        assert_attributes(attrs, names, textinput)
+      end
+    end
+
+
     def assert_dublin_core(elems, target)
-      elems.each do |name, value|
-        assert_equal(value, target.__send__("dc_#{name}"))
+      _wrap_assertion do
+        elems.each do |name, value|
+          assert_equal(value, target.__send__("dc_#{name}"))
+        end
       end
     end
     
     def assert_syndication(elems, target)
-      elems.each do |name, value|
-        assert_equal(value, target.__send__("sy_#{name}"))
+      _wrap_assertion do
+        elems.each do |name, value|
+          assert_equal(value, target.__send__("sy_#{name}"))
+        end
       end
     end
     
     def assert_content(elems, target)
-      elems.each do |name, value|
-        assert_equal(value, target.__send__("content_#{name}"))
+      _wrap_assertion do
+        elems.each do |name, value|
+          assert_equal(value, target.__send__("content_#{name}"))
+        end
       end
     end
     
-    def assert_trackback(elems, target)
-      elems.each do |name, value|
-        assert_equal(value, target.__send__("trackback_#{name}"))
+    def assert_trackback(attrs, target)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
+        if n_attrs["ping"]
+          assert_equal(n_attrs["ping"], target.trackback_ping)
+        end
+        if n_attrs["abouts"]
+          n_attrs["abouts"].each_with_index do |about, i|
+            assert_equal(about, target.trackback_abouts[i].value)
+          end
+        end
       end
     end
+
+
+    def assert_attributes(attrs, names, target)
+      _wrap_assertion do
+        n_attrs = normalized_attrs(attrs)
+        names.each do |name|
+          value = n_attrs[name]
+          if value.is_a?(Time)
+            actual = target.__send__(name)
+            assert_instance_of(Time, actual)
+            assert_equal(value.to_i, actual.to_i)
+          elsif value
+            assert_equal(value, target.__send__(name))
+          end
+        end
+      end
+    end
+    
+    def normalized_attrs(attrs)
+      n_attrs = {}
+      attrs.each do |name, value|
+        n_attrs[name.to_s] = value
+      end
+      n_attrs
+    end
     
   end
 end
diff --git a/test/rss/test_1.0.rb b/test/rss/test_1.0.rb
index e6a81af2bd..c37bd84616 100644
--- a/test/rss/test_1.0.rb
+++ b/test/rss/test_1.0.rb
@@ -19,7 +19,7 @@ module RSS
       
       version = "1.0"
       encoding = "UTF-8"
-      standalone = "no"
+      standalone = false
       
       rdf = RDF.new(version, encoding, standalone)
       
@@ -27,9 +27,10 @@ module RSS
       
       xmldecl = doc.xml_decl
       
-      %w(version encoding standalone).each do |x|
+      %w(version encoding).each do |x|
         assert_equal(instance_eval(x), xmldecl.send(x))
       end
+      assert_equal(standalone, !xmldecl.standalone.nil?)
       
       assert_equal(@rdf_uri, doc.root.namespace)
       
diff --git a/test/rss/test_maker_0.9.rb b/test/rss/test_maker_0.9.rb
index df8cd5fe11..5f356cc8c4 100644
--- a/test/rss/test_maker_0.9.rb
+++ b/test/rss/test_maker_0.9.rb
@@ -55,8 +55,14 @@ module RSS
       webMaster = "web master"
       rating = "6"
       docs = "http://foo.com/doc"
-      skipDays = "Sunday"
-      skipHours = "13"
+      skipDays = [
+        "Sunday",
+        "Monday",
+      ]
+      skipHours = [
+        0,
+        13,
+      ]
       pubDate = Time.now
       lastBuildDate = Time.now
       
@@ -70,11 +76,18 @@ module RSS
         maker.channel.webMaster = webMaster
         maker.channel.rating = rating
         maker.channel.docs = docs
-        maker.channel.skipDays = skipDays
-        maker.channel.skipHours = skipHours
         maker.channel.pubDate = pubDate
         maker.channel.lastBuildDate = lastBuildDate
 
+        skipDays.each do |day|
+          new_day = maker.channel.skipDays.new_day
+          new_day.content = day
+        end
+        skipHours.each do |hour|
+          new_hour = maker.channel.skipHours.new_hour
+          new_hour.content = hour
+        end
+        
         setup_dummy_image(maker)
       end
       channel = rss.channel
@@ -88,11 +101,16 @@ module RSS
       assert_equal(webMaster, channel.webMaster)
       assert_equal(rating, channel.rating)
       assert_equal(docs, channel.docs)
-      assert_equal(skipDays, channel.skipDays)
-      assert_equal(skipHours, channel.skipHours)
       assert_equal(pubDate, channel.pubDate)
       assert_equal(lastBuildDate, channel.lastBuildDate)
 
+      skipDays.each_with_index do |day, i|
+        assert_equal(day, channel.skipDays.days[i].content)
+      end
+      skipHours.each_with_index do |hour, i|
+        assert_equal(hour, channel.skipHours.hours[i].content)
+      end
+      
       assert(channel.items.empty?)
       assert_not_nil(channel.image)
       assert_nil(channel.textInput)
diff --git a/test/rss/test_maker_2.0.rb b/test/rss/test_maker_2.0.rb
index b0752f985f..dc08ada34b 100644
--- a/test/rss/test_maker_2.0.rb
+++ b/test/rss/test_maker_2.0.rb
@@ -51,11 +51,20 @@ module RSS
       webMaster = "web master"
       rating = "6"
       docs = "http://foo.com/doc"
-      skipDays = "Sunday"
-      skipHours = "13"
+      skipDays = [
+        "Sunday",
+        "Monday",
+      ]
+      skipHours = [
+        0,
+        13,
+      ]
       pubDate = Time.now
       lastBuildDate = Time.now
-      category = "Nespapers"
+      categories = [
+        "Nespapers",
+        "misc",
+      ]
       generator = "RSS Maker"
       ttl = 60
       
@@ -69,11 +78,23 @@ module RSS
         maker.channel.webMaster = webMaster
         maker.channel.rating = rating
         maker.channel.docs = docs
-        maker.channel.skipDays = skipDays
-        maker.channel.skipHours = skipHours
         maker.channel.pubDate = pubDate
         maker.channel.lastBuildDate = lastBuildDate
-        maker.channel.category = category
+
+        skipDays.each do |day|
+          new_day = maker.channel.skipDays.new_day
+          new_day.content = day
+        end
+        skipHours.each do |hour|
+          new_hour = maker.channel.skipHours.new_hour
+          new_hour.content = hour
+        end
+        
+        categories.each do |category|
+          new_category = maker.channel.categories.new_category
+          new_category.content = category
+        end
+        
         maker.channel.generator = generator
         maker.channel.ttl = ttl
       end
@@ -88,11 +109,20 @@ module RSS
       assert_equal(webMaster, channel.webMaster)
       assert_equal(rating, channel.rating)
       assert_equal(docs, channel.docs)
-      assert_equal(skipDays, channel.skipDays)
-      assert_equal(skipHours, channel.skipHours)
       assert_equal(pubDate, channel.pubDate)
       assert_equal(lastBuildDate, channel.lastBuildDate)
-      assert_equal(category, channel.category)
+
+      skipDays.each_with_index do |day, i|
+        assert_equal(day, channel.skipDays.days[i].content)
+      end
+      skipHours.each_with_index do |hour, i|
+        assert_equal(hour, channel.skipHours.hours[i].content)
+      end
+      
+      channel.categories.each_with_index do |category, i|
+        assert_equal(categories[i], category.content)
+      end
+      
       assert_equal(generator, channel.generator)
       assert_equal(ttl, channel.ttl)
 
@@ -519,11 +549,11 @@ module RSS
         setup_dummy_channel(maker)
         setup_dummy_item(maker)
 
-        category = maker.items.last.category
+        category = maker.items.last.categories.new_category
         category.domain = domain
         category.content = content
       end
-      category = rss.channel.items.last.category
+      category = rss.channel.items.last.categories.last
       assert_equal(domain, category.domain)
       assert_equal(content, category.content)
     end
@@ -535,10 +565,10 @@ module RSS
         setup_dummy_channel(maker)
         setup_dummy_item(maker)
 
-        category = maker.items.last.category
+        category = maker.items.last.categories.new_category
         # category.content = content
       end
-      assert_nil(rss.channel.items.last.category)
+      assert(rss.channel.items.last.categories.empty?)
     end
     
     def test_textInput
diff --git a/test/rss/test_maker_content.rb b/test/rss/test_maker_content.rb
index faadd87131..c29d75a649 100644
--- a/test/rss/test_maker_content.rb
+++ b/test/rss/test_maker_content.rb
@@ -14,7 +14,7 @@ module RSS
     end
 
     def test_rss10
-      rss = RSS::Maker.make("1.0", ["content"]) do |maker|
+      rss = RSS::Maker.make("1.0") do |maker|
         setup_dummy_channel(maker)
 
         setup_dummy_item(maker)
diff --git a/test/rss/test_maker_dc.rb b/test/rss/test_maker_dc.rb
index 512622d29f..0a4a4d42cf 100644
--- a/test/rss/test_maker_dc.rb
+++ b/test/rss/test_maker_dc.rb
@@ -34,7 +34,7 @@ module RSS
     end
 
     def test_rss10
-      rss = RSS::Maker.make("1.0", ["dublincore"]) do |maker|
+      rss = RSS::Maker.make("1.0") do |maker|
         setup_dummy_channel(maker)
         set_elements(maker.channel)
 
diff --git a/test/rss/test_maker_sy.rb b/test/rss/test_maker_sy.rb
index c41ec1d310..58e95d917a 100644
--- a/test/rss/test_maker_sy.rb
+++ b/test/rss/test_maker_sy.rb
@@ -21,7 +21,7 @@ module RSS
     end
 
     def test_rss10
-      rss = RSS::Maker.make("1.0", ["syndication"]) do |maker|
+      rss = RSS::Maker.make("1.0") do |maker|
         setup_dummy_channel(maker)
         set_elements(maker.channel)
       end
diff --git a/test/rss/test_maker_trackback.rb b/test/rss/test_maker_trackback.rb
index bffa60e963..e90bb600a3 100644
--- a/test/rss/test_maker_trackback.rb
+++ b/test/rss/test_maker_trackback.rb
@@ -10,18 +10,23 @@ module RSS
       
       @elements = {
         :ping => "http://bar.com/tb.cgi?tb_id=rssplustrackback",
-        :about => "http://foo.com/trackback/tb.cgi?tb_id=20020923",
+        :abouts => [
+          "http://foo.com/trackback/tb.cgi?tb_id=20020923",
+          "http://bar.com/trackback/tb.cgi?tb_id=20041114",
+        ],
       }
     end
 
     def test_rss10
-      rss = RSS::Maker.make("1.0", ["trackback"]) do |maker|
+      rss = RSS::Maker.make("1.0") do |maker|
         setup_dummy_channel(maker)
 
         setup_dummy_item(maker)
         item = maker.items.last
-        @elements.each do |name, value|
-          item.__send__("#{accessor_name(name)}=", value)
+        item.trackback_ping = @elements[:ping]
+        @elements[:abouts].each do |about|
+          new_about = item.trackback_abouts.new_about
+          new_about.value = about
         end
       end
       assert_trackback(@elements, rss.items.last)
diff --git a/test/rss/test_parser.rb b/test/rss/test_parser.rb
index de4894997f..019030bcce 100644
--- a/test/rss/test_parser.rb
+++ b/test/rss/test_parser.rb
@@ -116,7 +116,7 @@ EOR
 
     def test_channel
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "channel", "about")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "channel", "rdf:about")
 <channel />
 EOR
 
@@ -145,7 +145,7 @@ EOR
 </channel>
 EOR
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "image", "resource")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "image", "rdf:resource")
 <channel rdf:about="http://example.com/">
   <title>hoge</title>
   <link>http://example.com/</link>
@@ -194,7 +194,7 @@ EOR
 </channel>
 EOR
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "textinput", "resource")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "textinput", "rdf:resource")
 <channel rdf:about="http://example.com/">
   <title>hoge</title>
   <link>http://example.com/</link>
@@ -257,7 +257,7 @@ EOR
 
     def test_image
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "image", "about")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "image", "rdf:about")
 #{make_channel}
 <image>
 </image>
@@ -314,7 +314,7 @@ EOR
 
     def test_item
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "item", "about")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "item", "rdf:about")
 #{make_channel}
 #{make_image}
 <item>
@@ -371,7 +371,7 @@ EOR
 
     def test_textinput
 
-      assert_parse(make_RDF(<<-EOR), :missing_attribute, "textinput", "about")
+      assert_parse(make_RDF(<<-EOR), :missing_attribute, "textinput", "rdf:about")
 #{make_channel}
 #{make_image}
 #{make_item}
diff --git a/test/rss/test_to_s.rb b/test/rss/test_to_s.rb
new file mode 100644
index 0000000000..e2263ca17c
--- /dev/null
+++ b/test/rss/test_to_s.rb
@@ -0,0 +1,440 @@
+require "rexml/document"
+
+require "rss-testcase"
+
+require "rss/maker"
+require "rss/1.0"
+require "rss/2.0"
+require "rss/content"
+require "rss/dublincore"
+require "rss/syndication"
+require "rss/trackback"
+
+module RSS
+  class TestToS < TestCase
+    
+    def setup
+      @image_url = "http://example.com/foo.png"
+      @textinput_link = "http://example.com/search.cgi"
+      @item_links = [
+        "http://example.com/1",
+        "http://example.com/2",
+      ]
+      
+      setup_xml_declaration_info
+      setup_xml_stylesheet_infos
+      setup_channel_info
+      setup_item_infos
+      setup_image_info
+      setup_textinput_info
+
+      setup_dublin_core_info
+      setup_syndication_info
+      setup_content_info
+      setup_trackback_info
+    end
+
+    def test_to_s_10
+      rss = RSS::Maker.make("1.0") do |maker|
+        setup_full(maker)
+      end
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel10(@channel_info, rss.channel)
+      assert_items10(@item_infos, rss.items)
+      rss.items.each do |item|
+        assert_trackback(@trackback_info, item)
+      end
+      assert_image10(@image_info, rss.image)
+      assert_textinput10(@textinput_info, rss.textinput)
+
+      rss = RSS::Parser.parse(rss.to_s)
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel10(@channel_info, rss.channel)
+      assert_items10(@item_infos, rss.items)
+      assert_image10(@image_info, rss.image)
+      assert_textinput10(@textinput_info, rss.textinput)
+    end
+    
+    def test_to_s_09
+      rss = RSS::Maker.make("0.9") do |maker|
+        setup_full(maker)
+      end
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel09(@channel_info, rss.channel)
+      assert_items09(@item_infos, rss.items)
+      assert_image09(@image_info, rss.image)
+      assert_textinput09(@textinput_info, rss.textinput)
+
+      rss = RSS::Parser.parse(rss.to_s)
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel09(@channel_info, rss.channel)
+      assert_items09(@item_infos, rss.items)
+      assert_image09(@image_info, rss.image)
+      assert_textinput09(@textinput_info, rss.textinput)
+    end
+    
+    def test_to_s_20
+      rss = RSS::Maker.make("2.0") do |maker|
+        setup_full(maker)
+      end
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel20(@channel_info, rss.channel)
+      assert_items20(@item_infos, rss.items)
+      assert_image20(@image_info, rss.image)
+      assert_textinput20(@textinput_info, rss.textinput)
+
+      rss = RSS::Parser.parse(rss.to_s)
+
+      assert_xml_declaration(@version, @encoding, @standalone, rss)
+      assert_xml_stylesheets(@xs_infos, rss.xml_stylesheets)
+      assert_channel20(@channel_info, rss.channel)
+      assert_items20(@item_infos, rss.items)
+      assert_image20(@image_info, rss.image)
+      assert_textinput20(@textinput_info, rss.textinput)
+    end
+    
+    private
+    def setup_xml_declaration_info
+      @version = "1.0"
+      @encoding = "UTF-8"
+      @standalone = false
+    end
+
+    def setup_xml_stylesheet_infos
+      @xs_infos = [
+        {
+          "href" => "XXX.xsl",
+          "type" => "text/xsl",
+          "title" => "XXX",
+          "media" => "print",
+          "alternate" => "no",
+        },
+        {
+          "href" => "YYY.css",
+          "type" => "text/css",
+          "title" => "YYY",
+          "media" => "all",
+          "alternate" => "no",
+        },
+      ]
+    end
+
+    def setup_channel_info
+      @channel_info = {
+        "about" => "http://example.com/index.rdf",
+        "title" => "Sample RSS",
+        "link" => "http://example.com/",
+        "description" => "Sample\n\n\n\n\nSite",
+        "language" => "en",
+        "copyright" => "FDL",
+        "managingEditor" => "foo@example.com",
+        "webMaster" => "webmaster@example.com",
+        "rating" => '(PICS-1.1 "http://www.rsac.org/ratingsv01.html" l gen true comment "RSACi North America Server" for "http://www.rsac.org" on "1996.04.16T08:15-0500" r (n 0 s 0 v 0 l 0))',
+        "docs" => "http://backend.userland.com/rss091",
+        "skipDays" => [
+          "Monday",
+          "Friday",
+        ],
+        "skipHours" => [
+          12,
+          23,
+        ],
+        "date" => Time.now,
+        "lastBuildDate" => Time.now - 3600,
+        "generator" => "RSS Maker",
+        "ttl" => 60,
+        "cloud" => {
+          "domain" => "rpc.sys.com",
+          "port" => "80",
+          "path" => "/RPC2",
+          "registerProcedure" => "myCloud.rssPleaseNotify",
+          "protocol" => "xml-rpc",
+        },
+        "category" => {
+          "domain" => "http://example.com/misc/",
+          "content" => "misc",
+        },
+
+        "image" => {
+          "resource" => @image_url,
+        },
+
+        "textinput" => {
+          "resource" => @textinput_link,
+        },
+
+        "items" => @item_links.collect{|link| {"resource" => link}},
+      }
+    end
+
+    def setup_item_infos
+      @item_infos = [
+        {
+          "title" => "Sample item1",
+          "link" => @item_links[0],
+          "description" => "Sample description1",
+          "date" => Time.now - 3600,
+          "author" => "foo@example.com",
+          "comments" => "http://example.com/1/comments",
+          "guid" => {
+            "isPermaLink" => "ture",
+            "content" => "http://example.com/1",
+          },
+          "enclosure" => {
+            "url" => "http://example.com/1.mp3",
+            "length" => "100",
+            "type" => "audio/mpeg",
+          },
+          "source" => {
+            "url" => "http:/example.com/",
+            "content" => "Sample site",
+          },
+          "category" => {
+            "domain" => "http://example.com/misc/",
+            "content" => "misc",
+          },
+        },
+
+        {
+          "title" => "Sample item2",
+          "link" => @item_links[1],
+          "description" => "Sample description2",
+          "date" => Time.now - 7200,
+          "author" => "foo@example.com",
+          "comments" => "http://example.com/2/comments",
+          "guid" => {
+            "isPermaLink" => "false",
+            "content" => "http://example.com/2",
+          },
+          "enclosure" => {
+            "url" => "http://example.com/2.mp3",
+            "length" => "200",
+            "type" => "audio/mpeg",
+          },
+          "source" => {
+            "url" => "http:/example.com/",
+            "content" => "Sample site",
+          },
+          "category" => {
+            "domain" => "http://example.com/misc/",
+            "content" => "misc",
+          },
+        },
+      ]
+    end
+
+    def setup_image_info
+      @image_info = {
+        "title" => "Sample image",
+        "url" => @image_url,
+        "width" => "88",
+        "height" => "31",
+        "description" => "Sample",
+      }
+    end
+
+    def setup_textinput_info
+      @textinput_info = {
+        "title" => "Sample textinput",
+        "description" => "Search",
+        "name" => "key",
+        "link" => @textinput_link,
+      }
+    end
+
+    def setup_dublin_core_info
+      @dc_info = {
+        "title" => "DC title",
+        "description" => "DC desc",
+        "creator" => "DC creator",
+        "subject" => "DC subject",
+        "publisher" => "DC publisher",
+        "contributor" => "DC contributor",
+        "type" => "DC type",
+        "format" => "DC format",
+        "identifier" => "DC identifier",
+        "source" => "DC source",
+        "language" => "ja",
+        "relation" => "DC relation",
+        "coverage" => "DC coverage",
+        "rights" => "DC rights",
+        "date" => Time.now - 60,
+      }
+    end
+
+    def setup_syndication_info
+      @sy_info = {
+        "updatePeriod" => "hourly",
+        "updateFrequency" => 2,
+        "updateBase" => Time.now - 3600,
+      }
+    end
+    
+    def setup_content_info
+      @content_info = {
+        "encoded" => "<p>p</p>",
+      }
+    end
+    
+    def setup_trackback_info
+      @trackback_info = {
+        "ping" => "http://example.com/tb.cgi?tb_id=XXX",
+        "abouts" => [
+          "http://example.net/tb.cgi?tb_id=YYY",
+          "http://example.org/tb.cgi?tb_id=ZZZ",
+        ]
+      }
+    end
+
+
+    def setup_full(maker)
+      setup_xml_declaration(maker)
+      setup_xml_stylesheets(maker)
+      setup_channel(maker)
+      setup_image(maker)
+      setup_items(maker)
+      setup_textinput(maker)
+    end
+
+    def setup_xml_declaration(maker)
+      %w(version encoding standalone).each do |name|
+        maker.__send__("#{name}=", instance_eval("@#{name}"))
+      end
+    end
+
+    def setup_xml_stylesheets(maker)
+      @xs_infos.each do |info|
+        xs = maker.xml_stylesheets.new_xml_stylesheet
+        info.each do |name, value|
+          xs.__send__("#{name}=", value)
+        end
+      end
+    end
+
+    def setup_channel(maker)
+      channel = maker.channel
+      info = @channel_info
+      
+      %w(about title link description language copyright
+         managingEditor webMaster rating docs date
+         lastBuildDate generator ttl).each do |name|
+        channel.__send__("#{name}=", info[name])
+      end
+
+      skipDays = channel.skipDays
+      info["skipDays"].each do |day|
+        new_day = skipDays.new_day
+        new_day.content = day
+      end
+
+      skipHours = channel.skipHours
+      info["skipHours"].each do |hour|
+        new_hour = skipHours.new_hour
+        new_hour.content = hour
+      end
+      
+      cloud = channel.cloud
+      %w(domain port path registerProcedure protocol).each do |name|
+        cloud.__send__("#{name}=", info["cloud"][name])
+      end
+
+      category = channel.categories.new_category
+      %w(domain content).each do |name|
+        category.__send__("#{name}=", info["category"][name])
+      end
+    end
+    
+    def setup_image(maker)
+      image = maker.image
+      info = @image_info
+
+      %w(title url width height description).each do |name|
+        image.__send__("#{name}=", info[name])
+      end
+    end
+    
+    def setup_items(maker)
+      items = maker.items
+
+      @item_infos.each do |info|
+        item = items.new_item
+        %w(title link description date author comments).each do |name|
+          item.__send__("#{name}=", info[name])
+        end
+        
+        guid = item.guid
+        %w(isPermaLink content).each do |name|
+          guid.__send__("#{name}=", info["guid"][name])
+        end
+
+        enclosure = item.enclosure
+        %w(url length type).each do |name|
+          enclosure.__send__("#{name}=", info["enclosure"][name])
+        end
+
+        source = item.source
+        %w(url content).each do |name|
+          source.__send__("#{name}=", info["source"][name])
+        end
+
+        category = item.categories.new_category
+        %w(domain content).each do |name|
+          category.__send__("#{name}=", info["category"][name])
+        end
+
+        setup_trackback(item)
+      end
+    end
+
+    def setup_textinput(maker)
+      textinput = maker.textinput
+      info = @textinput_info
+
+      %w(title description name link).each do |name|
+        textinput.__send__("#{name}=", info[name])
+      end
+    end
+
+    def setup_content(target)
+      prefix = "content"
+      %w(encoded).each do |name|
+        target.__send__("#{prefix}_#{name}=", @content_info[name])
+      end
+    end
+    
+    def setup_dublin_core(target)
+      prefix = "dc"
+      %w(title description creator subject publisher
+        contributor type format identifier source language
+        relation coverage rights).each do |name|
+        target.__send__("#{prefix}_#{name}=", @dc_info[name])
+      end
+    end
+    
+    def setup_syndicate(target)
+      prefix = "sy"
+      %w(updatePeriod updateFrequency updateBase).each do |name|
+        target.__send__("#{prefix}_#{name}=", @sy_info[name])
+      end
+    end
+    
+    def setup_trackback(target)
+      target.trackback_ping = @trackback_info["ping"]
+      @trackback_info["abouts"].each do |about|
+        new_about = target.trackback_abouts.new_about
+        new_about.value = about
+      end
+    end
+    
+  end
+end
diff --git a/test/rss/test_trackback.rb b/test/rss/test_trackback.rb
index bfe39d005b..a3f023e887 100644
--- a/test/rss/test_trackback.rb
+++ b/test/rss/test_trackback.rb
@@ -88,19 +88,19 @@ EOR
       @elems.each do |name, value|
         @parents.each do |parent|
           accessor = "#{RSS::TRACKBACK_PREFIX}_#{name}"
-          target_accessor = "resource"
-          target = @rss.send(parent).send(accessor)
+          target = @rss.send(parent)
           target20 = @rss20.channel.send(parent, -1)
-          assert_equal(value, target.send(target_accessor))
+          assert_equal(value, target.send(accessor))
           assert_equal(value, target20.send(accessor))
-          target.send("#{target_accessor}=", new_value[name].to_s)
           if name == :about
             # abount is zero or more
+            target.send("#{accessor}=", 0, new_value[name].to_s)
             target20.send("#{accessor}=", 0, new_value[name].to_s)
           else
+            target.send("#{accessor}=", new_value[name].to_s)
             target20.send("#{accessor}=", new_value[name].to_s)
           end
-          assert_equal(new_value[name], target.send(target_accessor))
+          assert_equal(new_value[name], target.send(accessor))
           assert_equal(new_value[name], target20.send(accessor))
         end
       end
diff --git a/test/rss/test_xml-stylesheet.rb b/test/rss/test_xml-stylesheet.rb
index ab16d6e2ff..c88a858f56 100644
--- a/test/rss/test_xml-stylesheet.rb
+++ b/test/rss/test_xml-stylesheet.rb
@@ -14,7 +14,7 @@ module RSS
         {:media => "print", :title => "FOO"},
         {:charset => "UTF-8", :alternate => "yes"},
       ].each do |attrs|
-        assert_xml_stylesheet_attrs(XMLStyleSheet.new(*attrs), attrs)
+        assert_xml_stylesheet_attrs(attrs, XMLStyleSheet.new(*attrs))
       end
     end
     
@@ -36,7 +36,7 @@ module RSS
          :alternate => "yes"},
       ].each do |attrs|
         target, contents = parse_pi(XMLStyleSheet.new(*attrs).to_s)
-        assert_xml_stylesheet(target, XMLStyleSheet.new(*contents), attrs)
+        assert_xml_stylesheet(target, attrs, XMLStyleSheet.new(*contents))
       end
     end
     
@@ -88,7 +88,7 @@ module RSS
         assert_equal(have_href_xsss.size, rss.xml_stylesheets.size)
         rss.xml_stylesheets.each_with_index do |stylesheet, i|
           target, = parse_pi(stylesheet.to_s)
-          assert_xml_stylesheet(target, stylesheet, have_href_xsss[i])
+          assert_xml_stylesheet(target, have_href_xsss[i], stylesheet)
         end
       end
     end