Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.843
diff -u -F^f -r1.843 common.inc
--- includes/common.inc	8 Jan 2009 19:09:49 -0000	1.843
+++ includes/common.inc	10 Jan 2009 02:38:15 -0000
@@ -3200,14 +3200,30 @@ function drupal_render(&$elements) {
   if (!isset($elements) || (isset($elements['#access']) && !$elements['#access'])) {
     return NULL;
   }
+  
+  // Never render elements twice.
+  // To force rerendering an element, unset #rendered_content.
+  if (isset($elements['#rendered_content'])) {
+    return $elements['#rendered_content'];
+  }
 
   // If the default values for this element haven't been loaded yet, populate
   // them.
-  if (!isset($elements['#defaults_loaded']) || !$elements['#defaults_loaded']) {
-    if ((!empty($elements['#type'])) && ($info = _element_info($elements['#type']))) {
-      $elements += $info;
-    }
+  if (empty($elements['#defaults_loaded']) && isset($elements['#type'])) {
+    $elements += _element_info($elements['#type']);
+  }
+  $elements += array('#title' => NULL, '#description' => NULL);
+  
+  // BACKWARD COMPATIBILITY:
+  // I did not yet convert the actual elements and form_alters to the new structure.
+  // TODO: Remove this, of course.
+  if (!isset($elements['#theme_children']) && isset($elements['#theme'])) {
+    $elements['#theme_children'] = $elements['#theme'];
   }
+  if (empty($elements['#theme_wrapper'])) {
+    $elements['#theme_wrapper'][] = !empty($elements['#type']) ? $elements['#type'] : 'markup';
+  }
+  // END BACKWARD COMPATIBILITY.
 
   // Make any final changes to the element before it is rendered. This means
   // that the $element or the children can be altered or corrected before the
@@ -3220,70 +3236,65 @@ function drupal_render(&$elements) {
     }
   }
 
-  $content = '';
   // Either the elements did not go through form_builder or one of the children
   // has a #weight.
   if (!isset($elements['#sorted'])) {
     uasort($elements, "element_sort");
   }
-  $elements += array('#title' => NULL, '#description' => NULL);
-  if (!isset($elements['#children'])) {
-    $children = element_children($elements);
-    // Render all the children that use a theme function.
-    if (isset($elements['#theme']) && empty($elements['#theme_used'])) {
-      $elements['#theme_used'] = TRUE;
-
-      $previous = array();
-      foreach (array('#type', '#prefix', '#suffix') as $key) {
-        $previous[$key] = isset($elements[$key]) ? $elements[$key] : NULL;
-      }
-      // If we rendered a single element, then we will skip the renderer.
-      if (empty($children)) {
-        $elements['#printed'] = TRUE;
-      }
-      else {
-        $elements['#markup'] = '';
-      }
-
-      unset($elements['#type'], $elements['#prefix'], $elements['#suffix']);
-      $content = theme($elements['#theme'], $elements);
-
-      foreach (array('#type', '#prefix', '#suffix') as $key) {
-        $elements[$key] = isset($previous[$key]) ? $previous[$key] : NULL;
-      }
-    }
-    // Render each of the children using drupal_render and concatenate them.
-    if (!isset($content) || $content === '') {
-      foreach ($children as $key) {
-        $content .= drupal_render($elements[$key]);
-      }
-    }
+  // Render all the element's children into a string.
+  // If #theme_children is set, this theme function will be called which is then
+  // responsible to render all children. If #theme_children is not set, the element's
+  // children will  be concatenated into a string by drupal_render_children.
+  if (isset($elements['#theme_children'])) {
+    $elements['#children'] = theme($elements['#theme_children'], $elements);
   }
-  if (isset($content) && $content !== '') {
-    $elements['#children'] = $content;
+  else {
+    $elements['#children'] = drupal_render_children(&$elements);
   }
-
-  // Until now, we rendered the children, here we render the element itself
-  if (!isset($elements['#printed'])) {
-    $content = theme(!empty($elements['#type']) ? $elements['#type'] : 'markup', $elements);
-    $elements['#printed'] = TRUE;
-  }
-
-  if (isset($content) && $content !== '') {
-    // Filter the outputted content and make any last changes before the
-    // content is sent to the browser. The changes are made on $content
-    // which allows the output'ed text to be filtered.
-    if (isset($elements['#post_render'])) {
-      foreach ($elements['#post_render'] as $function) {
-        if (drupal_function_exists($function)) {
-          $content = $function($content, $elements);
-        }
+  
+  // Let all theme functions in #theme_wrapper add markup around the rendered
+  // children.
+  foreach ($elements['#theme_wrapper'] as $theme_wrapper) {
+    // TODO: Would propably be nicer to just pass in $element['#children'] as a $content
+    // or $children argument, but that would require a change to all form element theme
+    // functions so I left it as it was for now.
+    $elements['#children'] = theme($theme_wrapper, $elements);
+  }
+  
+  $content = $elements['#children'];
+  
+  // Filter the outputted content and make any last changes before the
+  // content is sent to the browser. The changes are made on $content
+  // which allows the output'ed text to be filtered.
+  if (isset($elements['#post_render'])) {
+    foreach ($elements['#post_render'] as $function) {
+      if (drupal_function_exists($function)) {
+        $content = $function($content, $elements);
       }
     }
-    $prefix = isset($elements['#prefix']) ? $elements['#prefix'] : '';
-    $suffix = isset($elements['#suffix']) ? $elements['#suffix'] : '';
-    return $prefix . $content . $suffix;
   }
+  
+  $prefix = isset($elements['#prefix']) ? $elements['#prefix'] : '';
+  $suffix = isset($elements['#suffix']) ? $elements['#suffix'] : '';
+  
+  $elements['#rendered_content'] = $prefix . $content . $suffix;
+  return $elements['#rendered_content'];  
+}
+
+
+/**
+ * Render children of an element and concatenate them.
+ *
+ * This renders all children of an element using drupal_render() and then
+ * joins them together into a single string.
+ */
+function drupal_render_children($element) {
+  $output = '';
+  $children = element_children($element);
+  foreach ($children as $key) {
+    $output .= drupal_render($element[$key]);
+  }
+  return $output;
 }
 
 /**
Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.310
diff -u -F^f -r1.310 form.inc
--- includes/form.inc	30 Dec 2008 16:43:14 -0000	1.310
+++ includes/form.inc	10 Jan 2009 02:38:16 -0000
@@ -1347,15 +1347,21 @@ function _form_set_value(&$form_values, 
 
 /**
  * Retrieve the default properties for the defined element type.
+ * @todo
+ *    Remove leading underscore and move to common.inc? It's required by
+ *    drupal_render.
  */
 function _element_info($type, $refresh = NULL) {
   static $cache;
 
   $basic_defaults = array(
     '#description' => NULL,
+    '#title' => NULL,
     '#attributes' => array(),
     '#required' => FALSE,
+    '#theme_wrapper' => array(),
   );
+  
   if (!isset($cache) || $refresh) {
     $cache = array();
     foreach (module_implements('elements') as $module) {
@@ -2139,7 +2145,6 @@ function theme_textfield($element) {
   if (isset($element['#field_suffix'])) {
     $output .= ' <span class="field-suffix">' . $element['#field_suffix'] . '</span>';
   }
-
   return theme('form_element', $element, $output) . $extra;
 }