views_element_validate_tags($element, FormStateInterface $form_state)
Validation callback for query tags.
File
core/modules/views/views.module, line 798 Primarily Drupal hooks and global API functions to manipulate views.
Code
function views_element_validate_tags($element, FormStateInterface $form_state) {
$values = array_map('trim', explode(',', $element['#value']));
foreach ($values as $value) {
if (preg_match("/[^a-z_]/", $value)) {
$form_state->setError($element, t('The q