Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.415.2.7
diff -u -p -r1.415.2.7 theme.inc
--- includes/theme.inc	25 Jun 2008 07:56:31 -0000	1.415.2.7
+++ includes/theme.inc	1 Jul 2008 20:57:21 -0000
@@ -596,7 +596,27 @@ function theme() {
   }
   if (isset($info['function'])) {
     // The theme call is a function.
-    $output = call_user_func_array($info['function'], $args);
+
+    if (!empty($info['arguments'])) {
+      $count = 0;
+      foreach ($info['arguments'] as $name => $default) {
+        $variables[$name] = isset($args[$count]) ? $args[$count] : $default;
+        $count++;
+      }
+    }
+
+    if (isset($info['preprocess functions']) && is_array($info['preprocess functions'])) {
+      // This construct ensures that we can keep a reference through
+      // call_user_func_array.
+      $preprocess_args = array(&$variables, $hook);
+      foreach ($info['preprocess functions'] as $preprocess_function) {
+        if (function_exists($preprocess_function)) {
+          call_user_func_array($preprocess_function, $preprocess_args);
+        }
+      }
+    }
+
+    $output = call_user_func_array($info['function'], $variables);
   }
   else {
     // The theme call is a template.