$this->t('Execute PHP Code'), '#description' => $this->t('Execute some PHP code'), ); $form['execute']['code'] = array( '#type' => 'textarea', '#title' => t('PHP code to execute'), '#description' => t('Enter some code. Do not use <?php ?> tags.'), '#default_value' => (isset($_SESSION['devel_execute_code']) ? $_SESSION['devel_execute_code'] : ''), '#rows' => 20, ); $form['execute']['op'] = array('#type' => 'submit', '#value' => t('Execute')); $form['#redirect'] = FALSE; if (isset($_SESSION['devel_execute_code'])) { unset($_SESSION['devel_execute_code']); } return $form; } /** * {@inheritdoc} */ public function submitForm(array &$form, FormStateInterface $form_state) { ob_start(); $code = $form_state->getValue('code'); print eval($code); $_SESSION['devel_execute_code'] = $code; dpm(ob_get_clean()); } }