Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.823
diff -u -p -r1.823 common.inc
--- includes/common.inc	10 Nov 2008 05:22:59 -0000	1.823
+++ includes/common.inc	11 Nov 2008 16:04:18 -0000
@@ -2715,6 +2715,7 @@ function _drupal_bootstrap_full() {
   require_once DRUPAL_ROOT . '/includes/form.inc';
   require_once DRUPAL_ROOT . '/includes/mail.inc';
   require_once DRUPAL_ROOT . '/includes/actions.inc';
+  require_once DRUPAL_ROOT . '/includes/rdf.inc';
   // Set the Drupal custom error handler.
   set_error_handler('_drupal_error_handler');
   set_exception_handler('_drupal_exception_handler');
Index: includes/rdf.inc
===================================================================
RCS file: includes/rdf.inc
diff -N includes/rdf.inc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ includes/rdf.inc	11 Nov 2008 16:04:18 -0000
@@ -0,0 +1,57 @@
+<?php
+// $Id$
+
+/**
+ * @file
+ * Functions to handle RDF related features.
+ */
+
+/**
+ * Default GRDDL transformation profile for allowing RDF to be extracted from
+ * RDFa documents.
+ */
+define('GRDDL_PROFILE', 'http://ns.inria.fr/grddl/rdfa/');
+
+/**
+ * Execute hook_rdf_namespace() which is run during the page rendering in
+ * template_preprocess_page().
+ *
+ * Compact URIs (CURIEs) are useful when referring to RDF vocabulary terms.
+ * Modules can register specific RDF namespaces which will be included in the
+ * header of the XHTML output. Only one namespace can be assigned per prefix.
+ *
+ * Example of hook_rdf_namespace() implementation
+ * @code
+ *   function user_rdf_namespace() {
+ *     return array(
+ *       'sioc' => 'http://rdfs.org/sioc/ns#',
+ *       'foaf' => 'http://xmlns.com/foaf/0.1/',
+ *     );
+ *   }
+ * @endcode
+ *
+ * @return
+ *   An array containing all the RDF namespaces defined by the modules.
+ */
+function rdf_get_namespaces() {
+  $namespaces = array();
+
+  foreach (module_list() as $module) {
+    if ($module_namespaces = module_invoke($module, 'rdf_namespace')) {
+      // Loop through each namespace defined by the module and register the
+      // namespace if it has not been registered yet.
+      foreach ($module_namespaces as $prefix => $uri) {
+        if (!isset($namespaces[$prefix])) {
+          $namespaces[$prefix] = $uri;
+        }
+        // Prevent modules from overriding already defined prefixes.
+        elseif ($namespaces[$prefix] != $uri) {
+          drupal_set_message(t('The RDF namespace prefix %prefix cannot be defined twice with different URIs.', array('%prefix' => $prefix)), 'error');
+        }
+      }
+    }
+  }
+
+  return $namespaces;
+}
+
Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.450
diff -u -p -r1.450 theme.inc
--- includes/theme.inc	10 Nov 2008 15:40:03 -0000	1.450
+++ includes/theme.inc	11 Nov 2008 16:04:18 -0000
@@ -1885,6 +1885,14 @@ function template_preprocess_page(&$vari
   // Closure should be filled last.
   $variables['closure']           = theme('closure');
 
+  // Construct RDFa elements to annotate the page.
+  $xml_rdf_namespaces = array();
+  foreach (rdf_get_namespaces() as $prefix => $uri) {
+    $xml_rdf_namespaces[] = 'xmlns:' . $prefix . '="' . $uri . '"';
+  }
+  $variables['rdf_namespaces']    = implode(' ', $xml_rdf_namespaces);
+  $variables['grddl_profile']     = GRDDL_PROFILE;
+
   if ($node = menu_get_object()) {
     $variables['node'] = $node;
   }
Index: modules/system/system.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.module,v
retrieving revision 1.635
diff -u -p -r1.635 system.module
--- modules/system/system.module	31 Oct 2008 02:18:22 -0000	1.635
+++ modules/system/system.module	11 Nov 2008 16:04:19 -0000
@@ -197,6 +197,26 @@ function system_perm() {
 }
 
 /**
+ * Implementation of hook_rdf_namespace().
+ */
+function system_rdf_namespace() {
+  return array(
+    'admin'    => 'http://webns.net/mvcb/',
+    'content'  => 'http://purl.org/rss/1.0/modules/content/',
+    'dc'       => 'http://purl.org/dc/elements/1.1/',
+    'dcterms'  => 'http://purl.org/dc/terms/',
+    'foaf'     => 'http://xmlns.com/foaf/0.1/',
+    'owl'      => 'http://www.w3.org/2002/07/owl#',
+    'rdf'      => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
+    'rdfs'     => 'http://www.w3.org/2000/01/rdf-schema#',
+    'rss'      => 'http://purl.org/rss/1.0/',
+    'sioc'     => 'http://rdfs.org/sioc/ns#',
+    'xsi'      => 'http://www.w3.org/2001/XMLSchema-instance#',
+    'xsd'      => 'http://www.w3.org/2001/XMLSchema#',
+  );
+}
+
+/**
  * Implementation of hook_elements().
  */
 function system_elements() {
Index: themes/garland/page.tpl.php
===================================================================
RCS file: /cvs/drupal/drupal/themes/garland/page.tpl.php,v
retrieving revision 1.21
diff -u -p -r1.21 page.tpl.php
--- themes/garland/page.tpl.php	14 Sep 2008 02:03:35 -0000	1.21
+++ themes/garland/page.tpl.php	11 Nov 2008 16:04:19 -0000
@@ -1,9 +1,9 @@
 <?php
 // $Id: page.tpl.php,v 1.21 2008/09/14 02:03:35 webchick Exp $
-?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
-  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="<?php print $language->language ?>" lang="<?php print $language->language ?>" dir="<?php print $language->dir ?>">
-  <head>
+?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN"
+  "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="<?php print $language->language ?>" lang="<?php print $language->language ?>" dir="<?php print $language->dir ?>" <?php print $rdf_namespaces ?>>
+  <head profile="<?php print $grddl_profile ?>">
     <title><?php print $head_title ?></title>
     <?php print $head ?>
     <?php print $styles ?>