* 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.


git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@7319 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

14 files changed, 927 insertions, 509 deletions

diff --git a/lib/rss/0.9.rb b/lib/rss/0.9.rb
index c772e8087..20a229b92 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 563ed6642..9a61e456b 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 7fafb23ba..0a2d86860 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 c158c726c..66c3bc292 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 05578082b..6f26e20f4 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 894bcc0a2..ae22eb4fc 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 05fc46480..8ac5e7bbb 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 21222351f..91eb072ec 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 1ec59ab0b..ef78bf2f2 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 09b321337..e1da24418 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 375b7794f..73e352a73 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 b6afa24b9..a63bee8a6 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 e276305ec..5cbf65240 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|
@@ -31,24 +40,78 @@ 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
+        klass.__send__(:include, TrackBackUtils)
+
         %w(ping).each do |x|
-          klass.install_have_child_element("#{TRACKBACK_PREFIX}_#{x}")
+          var_name = "#{TRACKBACK_PREFIX}_#{x}"
+          klass_name = x.capitalize
+          klass.install_have_child_element(var_name)
+          klass.module_eval(<<-EOC, __FILE__, __LINE__)
+            undef #{var_name}
+            def #{var_name}
+              @#{var_name} and @#{var_name}.value
+            end
+
+            undef #{var_name}=
+            def #{var_name}=(value)
+              @#{var_name} = new_with_value_if_need(#{klass_name}, value)
+            end
+          EOC
         end
         
-        %w(about).each do |x|
-          klass.install_have_children_element("#{TRACKBACK_PREFIX}_#{x}")
+        [%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, __FILE__, __LINE__)
+            undef #{var_name}
+            def #{var_name}(*args)
+              if args.empty?
+                @#{var_name}.first and @#{var_name}.first.value
+              else
+                ret = @#{var_name}.send("[]", *args)
+                if ret.is_a?(Array)
+                  ret.collect {|x| x.value}
+                else
+                  ret.value
+                end
+              end
+            end
+
+            undef #{var_name}=
+            undef set_#{var_name}
+            def #{var_name}=(*args)
+              if args.size == 1
+                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_value_if_need(#{klass_name}, val)
+                  end
+                else
+                  new_val = new_with_value_if_need(#{klass_name}, new_val)
+                end
+                @#{var_name}.send("[]=", *(args[0..-2] + [new_val]))
+              end
+            end
+            alias set_#{var_name} #{var_name}=
+          EOC
         end
       end
     end
+  end
+
+  module TrackBackModel10
+    extend BaseModel
+    extend BaseTrackBackModel
 
     class Ping < Element
       include RSS10
@@ -71,26 +134,28 @@ module RSS
         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)
-        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
+        rv = tag(indent)
+        rv = @converter.convert(rv) if convert and @converter
+        rv
       end
 
       private
       def _attrs
         [
-          ["resource", true],
+          ["#{::RSS::RDF::PREFIX}:resource", true, "resource"],
         ]
       end
 
@@ -117,26 +182,28 @@ module RSS
         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)
-        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
+        rv = tag(indent)
+        rv = @converter.convert(rv) if convert and @converter
+        rv
       end
 
       private
       def _attrs
         [
-          ["resource", true],
+          ["#{::RSS::RDF::PREFIX}:resource", true, "resource"],
         ]
       end
 
@@ -144,91 +211,8 @@ module RSS
   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.install_have_child_element(var_name)
-          klass.module_eval(<<-EOC)
-            alias _#{var_name} #{var_name}
-            def #{var_name}
-              @#{var_name} and @#{var_name}.content
-            end
-
-            alias _#{var_name}= #{var_name}=
-            def #{var_name}=(content)
-              @#{var_name} = new_with_content_if_need(#{x.capitalize}, content)
-            end
-          EOC
-        end
-        
-        [%w(about s)].each do |x, postfix|
-          var_name = "#{TRACKBACK_PREFIX}_#{x}"
-          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}
-            def #{var_name}(*args)
-              if args.empty?
-                @#{var_name}.first and @#{var_name}.first.content
-              else
-                ret = @#{var_name}.send("[]", *args)
-                if ret.is_a?(Array)
-                  ret.collect {|x| x.content}
-                else
-                  ret.content
-                end
-              end
-            end
-
-            alias _#{var_name}= #{var_name}=
-            alias _set_#{var_name} set_#{var_name}
-            def #{var_name}=(*args)
-              if args.size == 1
-                item = new_with_content_if_need(#{x.capitalize}, 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)
-                  end
-                else
-                  new_val = new_with_content_if_need(#{x.capitalize}, new_val)
-                end
-                @#{var_name}.send("[]=", *(args[0..-2] + [new_val]))
-              end
-            end
-            alias set_#{var_name} #{var_name}=
-          EOC
-        end
-      end
-    end
-
-    private
-    def new_with_content(klass, content)
-      obj = klass.new
-      obj.content = content
-      obj
-    end
-
-    def new_with_content_if_need(klass, content)
-      if content.is_a?(klass)
-        content
-      else
-        new_with_content(klass, content)
-      end
-    end
-
+    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
+
+      alias_method(:value, :content)
+      alias_method(:value=, :content=)
+
+      def initialize(content=nil)
+        super()
+        @content = content
+      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
+      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 472ca9352..c5a11bad1 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)