Process variables for search-block-form.tpl.php.
The $variables array contains the following arguments:
function template_preprocess_search_block_form(&$variables) {
$variables['search'] = array();
$hidden = array();
// Provide variables named after form keys so themers can print each element independently.
foreach (element_children($variables['form']) as $key) {
$type = isset($variables['form'][$key]['#type']) ? $variables['form'][$key]['#type'] : '';
if ($type == 'hidden' || $type == 'token') {
$hidden[] = drupal_render($variables['form'][$key]);
}
else {
$variables['search'][$key] = drupal_render($variables['form'][$key]);
}
}
// Hidden form elements have no value to themers. No need for separation.
$variables['search']['hidden'] = implode($hidden);
// Collect all form elements to make it easier to print the whole form.
$variables['search_form'] = implode($variables['search']);
}