protected function definition_inner($mform)
 {
     // Load the configuration.
     $this->stackconfig = stack_utils::get_config();
     // Prepare input types.
     $this->typechoices = stack_input_factory::get_available_type_choices();
     // Prepare answer test types.
     $answertests = stack_ans_test_controller::get_available_ans_tests();
     // Algebraic Equivalence should be the default test, and first on the list.
     // This does not come first in the alphabet of all languages.
     $default = 'AlgEquiv';
     $defaultstr = stack_string($answertests[$default]);
     unset($answertests[$default]);
     $this->answertestchoices = array();
     foreach ($answertests as $test => $string) {
         $this->answertestchoices[$test] = stack_string($string);
     }
     stack_utils::sort_array($this->answertestchoices);
     $this->answertestchoices = array_merge(array($default => $defaultstr), $this->answertestchoices);
     // Prepare score mode choices.
     $this->scoremodechoices = array('=' => '=', '+' => '+', '-' => '-');
     $inputnames = $this->get_input_names_from_question_text();
     $prtnames = $this->get_prt_names_from_question();
     // Note that for the editor elements, we are using
     // $mform->getElement('prtincorrect')->setValue(...);
     // instead of setDefault, because setDefault does not work for editors.
     $mform->addHelpButton('questiontext', 'questiontext', 'qtype_stack');
     $mform->addRule('questiontext', stack_string('questiontextnonempty'), 'required', '', 'client');
     $qvars = $mform->createElement('textarea', 'questionvariables', stack_string('questionvariables'), array('rows' => 5, 'cols' => 80));
     $mform->insertElementBefore($qvars, 'questiontext');
     $mform->addHelpButton('questionvariables', 'questionvariables', 'qtype_stack');
     $seed = $mform->createElement('text', 'variantsselectionseed', stack_string('variantsselectionseed'), array('size' => 50));
     $mform->insertElementBefore($seed, 'questiontext');
     $mform->setType('variantsselectionseed', PARAM_RAW);
     $mform->addHelpButton('variantsselectionseed', 'variantsselectionseed', 'qtype_stack');
     $sf = $mform->createElement('editor', 'specificfeedback', get_string('specificfeedback', 'question'), array('rows' => 10), $this->editoroptions);
     $mform->insertElementBefore($sf, 'generalfeedback');
     $mform->getElement('specificfeedback')->setValue(array('text' => self::DEFAULT_SPECIFIC_FEEDBACK));
     $mform->addHelpButton('specificfeedback', 'specificfeedback', 'qtype_stack');
     $mform->addHelpButton('generalfeedback', 'generalfeedback', 'qtype_stack');
     $mform->addElement('textarea', 'questionnote', stack_string('questionnote'), array('rows' => 2, 'cols' => 80));
     $mform->addHelpButton('questionnote', 'questionnote', 'qtype_stack');
     $mform->addElement('submit', 'verify', stack_string('verifyquestionandupdate'));
     $mform->registerNoSubmitButton('verify');
     // Inputs.
     foreach ($inputnames as $inputname => $counts) {
         $this->definition_input($inputname, $mform, $counts);
     }
     // PRTs.
     foreach ($prtnames as $prtname => $count) {
         $this->definition_prt($prtname, $mform, $count);
     }
     // Options.
     $mform->addElement('header', 'optionsheader', stack_string('options'));
     $mform->addElement('selectyesno', 'questionsimplify', stack_string('questionsimplify'));
     $mform->setDefault('questionsimplify', $this->stackconfig->questionsimplify);
     $mform->addHelpButton('questionsimplify', 'autosimplify', 'qtype_stack');
     $mform->addElement('selectyesno', 'assumepositive', stack_string('assumepositive'));
     $mform->setDefault('assumepositive', $this->stackconfig->assumepositive);
     $mform->addHelpButton('assumepositive', 'assumepositive', 'qtype_stack');
     $mform->addElement('editor', 'prtcorrect', stack_string('prtcorrectfeedback'), array('rows' => 1), $this->editoroptions);
     $mform->getElement('prtcorrect')->setValue(array('text' => $this->stackconfig->prtcorrect));
     $mform->addElement('editor', 'prtpartiallycorrect', stack_string('prtpartiallycorrectfeedback'), array('rows' => 1), $this->editoroptions);
     $mform->getElement('prtpartiallycorrect')->setValue(array('text' => $this->stackconfig->prtpartiallycorrect));
     $mform->addElement('editor', 'prtincorrect', stack_string('prtincorrectfeedback'), array('rows' => 1), $this->editoroptions);
     $mform->getElement('prtincorrect')->setValue(array('text' => $this->stackconfig->prtincorrect));
     $mform->addElement('select', 'multiplicationsign', stack_string('multiplicationsign'), stack_options::get_multiplication_sign_options());
     $mform->setDefault('multiplicationsign', $this->stackconfig->multiplicationsign);
     $mform->addHelpButton('multiplicationsign', 'multiplicationsign', 'qtype_stack');
     $mform->addElement('selectyesno', 'sqrtsign', stack_string('sqrtsign'));
     $mform->setDefault('sqrtsign', $this->stackconfig->sqrtsign);
     $mform->addHelpButton('sqrtsign', 'sqrtsign', 'qtype_stack');
     $mform->addElement('select', 'complexno', stack_string('complexno'), stack_options::get_complex_no_options());
     $mform->setDefault('complexno', $this->stackconfig->complexno);
     $mform->addHelpButton('complexno', 'complexno', 'qtype_stack');
     $mform->addElement('select', 'inversetrig', stack_string('inversetrig'), stack_options::get_inverse_trig_options());
     $mform->setDefault('inversetrig', $this->stackconfig->inversetrig);
     $mform->addHelpButton('inversetrig', 'inversetrig', 'qtype_stack');
     $mform->addElement('select', 'matrixparens', stack_string('matrixparens'), stack_options::get_matrix_parens_options());
     $mform->setDefault('matrixparens', $this->stackconfig->matrixparens);
     $mform->addHelpButton('matrixparens', 'matrixparens', 'qtype_stack');
     // Hints.
     $this->add_interactive_settings();
     // Replace standard penalty input at the bottom with the one we want.
     $mform->removeElement('multitriesheader');
     $mform->removeElement('penalty');
     $pen = $mform->createElement('text', 'penalty', stack_string('penalty'), array('size' => 5));
     $mform->insertElementBefore($pen, 'generalfeedback');
     $mform->setType('penalty', PARAM_FLOAT);
     $mform->addHelpButton('penalty', 'penalty', 'qtype_stack');
     $mform->setDefault('penalty', 0.1);
     $mform->addRule('penalty', null, 'required', null, 'client');
 }