[Summary view]

Differences Between: [Versions 310 and 402] [Versions 311 and 402] [Versions 39 and 402] [Versions 400 and 402] [Versions 401 and 402]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Question type class for the multi-answer question type.
  19   *
  20   * @package    qtype
  21   * @subpackage multianswer
  22   * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  require_once($CFG->dirroot . '/question/type/questiontypebase.php');
  30  require_once($CFG->dirroot . '/question/type/multichoice/question.php');
  31  require_once($CFG->dirroot . '/question/type/numerical/questiontype.php');
  32  
  33  /**
  34   * The multi-answer question type class.
  35   *
  36   * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  37   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  38   */
  39  class qtype_multianswer extends question_type {
  40  
  41      /**
  42       * Generate a subquestion replacement question class.
  43       *
  44       * Due to a bug, subquestions can be lost (see MDL-54724). This class exists to take
  45       * the place of those lost questions so that the system can keep working and inform
  46       * the user of the corrupted data.
  47       *
  48       * @return question_automatically_gradable The replacement question class.
  49       */
  50      public static function deleted_subquestion_replacement(): question_automatically_gradable {
  51          return new class implements question_automatically_gradable {
  52              public $qtype;
  53  
  54              public function __construct() {
  55                  $this->qtype = new class() {
  56                      public function name() {
  57                          return 'subquestion_replacement';
  58                      }
  59                  };
  60              }
  61  
  62              public function is_gradable_response(array $response) {
  63                  return false;
  64              }
  65  
  66              public function is_complete_response(array $response) {
  67                  return false;
  68              }
  69  
  70              public function is_same_response(array $prevresponse, array $newresponse) {
  71                  return false;
  72              }
  73  
  74              public function summarise_response(array $response) {
  75                  return '';
  76              }
  77  
  78              public function un_summarise_response(string $summary) {
  79                  return [];
  80              }
  81  
  82              public function classify_response(array $response) {
  83                  return [];
  84              }
  85  
  86              public function get_validation_error(array $response) {
  87                  return '';
  88              }
  89  
  90              public function grade_response(array $response) {
  91                  return [];
  92              }
  93  
  94              public function get_hint($hintnumber, question_attempt $qa) {
  95                  return;
  96              }
  97  
  98              public function get_right_answer_summary() {
  99                  return null;
 100              }
 101          };
 102      }
 103  
 104      public function can_analyse_responses() {
 105          return false;
 106      }
 107  
 108      public function get_question_options($question) {
 109          global $DB;
 110  
 111          parent::get_question_options($question);
 112          // Get relevant data indexed by positionkey from the multianswers table.
 113          $sequence = $DB->get_field('question_multianswer', 'sequence',
 114                  array('question' => $question->id), MUST_EXIST);
 115  
 116          if (empty($sequence)) {
 117              $question->options->questions = [];
 118              return true;
 119          }
 120  
 121          $wrappedquestions = $DB->get_records_list('question', 'id',
 122                  explode(',', $sequence), 'id ASC');
 123  
 124          // We want an array with question ids as index and the positions as values.
 125          $sequence = array_flip(explode(',', $sequence));
 126          array_walk($sequence, function(&$val) {
 127              $val++;
 128          });
 129  
 130          // Due to a bug, questions can be lost (see MDL-54724). So we first fill the question
 131          // options with this dummy "replacement" type. These are overridden in the loop below
 132          // leaving behind only those questions which no longer exist. The renderer then looks
 133          // for this deleted type to display information to the user about the corrupted question
 134          // data.
 135          foreach ($sequence as $seq) {
 136              $question->options->questions[$seq] = (object)[
 137                  'qtype' => 'subquestion_replacement',
 138                  'defaultmark' => 1,
 139                  'options' => (object)[
 140                      'answers' => []
 141                  ]
 142              ];
 143          }
 144  
 145          foreach ($wrappedquestions as $wrapped) {
 146              question_bank::get_qtype($wrapped->qtype)->get_question_options($wrapped);
 147              // For wrapped questions the maxgrade is always equal to the defaultmark,
 148              // there is no entry in the question_instances table for them.
 149              $wrapped->category = $question->categoryobject->id;
 150              $question->options->questions[$sequence[$wrapped->id]] = $wrapped;
 151          }
 152          $question->hints = $DB->get_records('question_hints',
 153                  array('questionid' => $question->id), 'id ASC');
 154  
 155          return true;
 156      }
 157  
 158      public function save_question_options($question) {
 159          global $DB;
 160          $result = new stdClass();
 161  
 162          // This function needs to be able to handle the case where the existing set of wrapped
 163          // questions does not match the new set of wrapped questions so that some need to be
 164          // created, some modified and some deleted.
 165          // Unfortunately the code currently simply overwrites existing ones in sequence. This
 166          // will make re-marking after a re-ordering of wrapped questions impossible and
 167          // will also create difficulties if questiontype specific tables reference the id.
 168  
 169          // First we get all the existing wrapped questions.
 170          $oldwrappedquestions = [];
 171          if (isset($question->oldparent)) {
 172              if ($oldwrappedids = $DB->get_field('question_multianswer', 'sequence',
 173                  ['question' => $question->oldparent])) {
 174                  $oldwrappedidsarray = explode(',', $oldwrappedids);
 175                  $unorderedquestions = $DB->get_records_list('question', 'id', $oldwrappedidsarray);
 176  
 177                  // Keep the order as given in the sequence field.
 178                  foreach ($oldwrappedidsarray as $questionid) {
 179                      if (isset($unorderedquestions[$questionid])) {
 180                          $oldwrappedquestions[] = $unorderedquestions[$questionid];
 181                      }
 182                  }
 183              }
 184          }
 185  
 186          $sequence = array();
 187          foreach ($question->options->questions as $wrapped) {
 188              if (!empty($wrapped)) {
 189                  // If we still have some old wrapped question ids, reuse the next of them.
 190                  $wrapped->id = 0;
 191                  if (is_array($oldwrappedquestions) &&
 192                          $oldwrappedquestion = array_shift($oldwrappedquestions)) {
 193                      $wrapped->oldid = $oldwrappedquestion->id;
 194                      if ($oldwrappedquestion->qtype != $wrapped->qtype) {
 195                          switch ($oldwrappedquestion->qtype) {
 196                              case 'multichoice':
 197                                  $DB->delete_records('qtype_multichoice_options',
 198                                          array('questionid' => $oldwrappedquestion->id));
 199                                  break;
 200                              case 'shortanswer':
 201                                  $DB->delete_records('qtype_shortanswer_options',
 202                                          array('questionid' => $oldwrappedquestion->id));
 203                                  break;
 204                              case 'numerical':
 205                                  $DB->delete_records('question_numerical',
 206                                          array('question' => $oldwrappedquestion->id));
 207                                  break;
 208                              default:
 209                                  throw new moodle_exception('qtypenotrecognized',
 210                                          'qtype_multianswer', '', $oldwrappedquestion->qtype);
 211                          }
 212                      }
 213                  }
 214              }
 215              $wrapped->name = $question->name;
 216              $wrapped->parent = $question->id;
 217              $previousid = $wrapped->id;
 218              // Save_question strips this extra bit off the category again.
 219              $wrapped->category = $question->category . ',1';
 220              $wrapped = question_bank::get_qtype($wrapped->qtype)->save_question(
 221                      $wrapped, clone($wrapped));
 222              $sequence[] = $wrapped->id;
 223              if ($previousid != 0 && $previousid != $wrapped->id) {
 224                  // For some reasons a new question has been created
 225                  // so delete the old one.
 226                  question_delete_question($previousid);
 227              }
 228          }
 229  
 230          // Delete redundant wrapped questions.
 231          if (is_array($oldwrappedquestions) && count($oldwrappedquestions)) {
 232              foreach ($oldwrappedquestions as $oldwrappedquestion) {
 233                  question_delete_question($oldwrappedquestion->id);
 234              }
 235          }
 236  
 237          if (!empty($sequence)) {
 238              $multianswer = new stdClass();
 239              $multianswer->question = $question->id;
 240              $multianswer->sequence = implode(',', $sequence);
 241              if ($oldid = $DB->get_field('question_multianswer', 'id',
 242                      array('question' => $question->id))) {
 243                  $multianswer->id = $oldid;
 244                  $DB->update_record('question_multianswer', $multianswer);
 245              } else {
 246                  $DB->insert_record('question_multianswer', $multianswer);
 247              }
 248          }
 249  
 250          $this->save_hints($question, true);
 251      }
 252  
 253      public function save_question($authorizedquestion, $form) {
 254          $question = qtype_multianswer_extract_question($form->questiontext);
 255          if (isset($authorizedquestion->id)) {
 256              $question->id = $authorizedquestion->id;
 257          }
 258  
 259          $question->category = $form->category;
 260          $form->defaultmark = $question->defaultmark;
 261          $form->questiontext = $question->questiontext;
 262          $form->questiontextformat = 0;
 263          $form->options = clone($question->options);
 264          unset($question->options);
 265          return parent::save_question($question, $form);
 266      }
 267  
 268      protected function make_hint($hint) {
 269          return question_hint_with_parts::load_from_record($hint);
 270      }
 271  
 272      public function delete_question($questionid, $contextid) {
 273          global $DB;
 274          $DB->delete_records('question_multianswer', array('question' => $questionid));
 275  
 276          parent::delete_question($questionid, $contextid);
 277      }
 278  
 279      protected function initialise_question_instance(question_definition $question, $questiondata) {
 280          parent::initialise_question_instance($question, $questiondata);
 281  
 282          $bits = preg_split('/\{#(\d+)\}/', $question->questiontext,
 283                  -1, PREG_SPLIT_DELIM_CAPTURE);
 284          $question->textfragments[0] = array_shift($bits);
 285          $i = 1;
 286          while (!empty($bits)) {
 287              $question->places[$i] = array_shift($bits);
 288              $question->textfragments[$i] = array_shift($bits);
 289              $i += 1;
 290          }
 291          foreach ($questiondata->options->questions as $key => $subqdata) {
 292              if ($subqdata->qtype == 'subquestion_replacement') {
 293                  continue;
 294              }
 295  
 296              $subqdata->contextid = $questiondata->contextid;
 297              if ($subqdata->qtype == 'multichoice') {
 298                  $answerregs = array();
 299                  if ($subqdata->options->shuffleanswers == 1 &&  isset($questiondata->options->shuffleanswers)
 300                      && $questiondata->options->shuffleanswers == 0 ) {
 301                      $subqdata->options->shuffleanswers = 0;
 302                  }
 303              }
 304              $question->subquestions[$key] = question_bank::make_question($subqdata);
 305              $question->subquestions[$key]->defaultmark = $subqdata->defaultmark;
 306              if (isset($subqdata->options->layout)) {
 307                  $question->subquestions[$key]->layout = $subqdata->options->layout;
 308              }
 309          }
 310      }
 311  
 312      public function get_random_guess_score($questiondata) {
 313          $fractionsum = 0;
 314          $fractionmax = 0;
 315          foreach ($questiondata->options->questions as $key => $subqdata) {
 316              if ($subqdata->qtype == 'subquestion_replacement') {
 317                  continue;
 318              }
 319              $fractionmax += $subqdata->defaultmark;
 320              $fractionsum += question_bank::get_qtype(
 321                      $subqdata->qtype)->get_random_guess_score($subqdata);
 322          }
 323          if ($fractionmax > question_utils::MARK_TOLERANCE) {
 324              return $fractionsum / $fractionmax;
 325          } else {
 326              return null;
 327          }
 328      }
 329  
 330      public function move_files($questionid, $oldcontextid, $newcontextid) {
 331          parent::move_files($questionid, $oldcontextid, $newcontextid);
 332          $this->move_files_in_hints($questionid, $oldcontextid, $newcontextid);
 333      }
 334  
 335      protected function delete_files($questionid, $contextid) {
 336          parent::delete_files($questionid, $contextid);
 337          $this->delete_files_in_hints($questionid, $contextid);
 338      }
 339  }
 340  
 341  
 342  // ANSWER_ALTERNATIVE regexes.
 343  define('ANSWER_ALTERNATIVE_FRACTION_REGEX',
 344         '=|%(-?[0-9]+(?:[.,][0-9]*)?)%');
 345  // For the syntax '(?<!' see http://www.perl.com/doc/manual/html/pod/perlre.html#item_C.
 346  define('ANSWER_ALTERNATIVE_ANSWER_REGEX',
 347          '.+?(?<!\\\\|&|&amp;)(?=[~#}]|$)');
 348  define('ANSWER_ALTERNATIVE_FEEDBACK_REGEX',
 349          '.*?(?<!\\\\)(?=[~}]|$)');
 350  define('ANSWER_ALTERNATIVE_REGEX',
 351         '(' . ANSWER_ALTERNATIVE_FRACTION_REGEX .')?' .
 352         '(' . ANSWER_ALTERNATIVE_ANSWER_REGEX . ')' .
 353         '(#(' . ANSWER_ALTERNATIVE_FEEDBACK_REGEX .'))?');
 354  
 355  // Parenthesis positions for ANSWER_ALTERNATIVE_REGEX.
 356  define('ANSWER_ALTERNATIVE_REGEX_PERCENTILE_FRACTION', 2);
 357  define('ANSWER_ALTERNATIVE_REGEX_FRACTION', 1);
 358  define('ANSWER_ALTERNATIVE_REGEX_ANSWER', 3);
 359  define('ANSWER_ALTERNATIVE_REGEX_FEEDBACK', 5);
 360  
 361  // NUMBER_FORMATED_ALTERNATIVE_ANSWER_REGEX is used
 362  // for identifying numerical answers in ANSWER_ALTERNATIVE_REGEX_ANSWER.
 363  define('NUMBER_REGEX',
 364          '-?(([0-9]+[.,]?[0-9]*|[.,][0-9]+)([eE][-+]?[0-9]+)?)');
 365  define('NUMERICAL_ALTERNATIVE_REGEX',
 366          '^(' . NUMBER_REGEX . ')(:' . NUMBER_REGEX . ')?$');
 367  
 368  // Parenthesis positions for NUMERICAL_FORMATED_ALTERNATIVE_ANSWER_REGEX.
 369  define('NUMERICAL_CORRECT_ANSWER', 1);
 370  define('NUMERICAL_ABS_ERROR_MARGIN', 6);
 371  
 372  // Remaining ANSWER regexes.
 373  define('ANSWER_TYPE_DEF_REGEX',
 374          '(NUMERICAL|NM)|(MULTICHOICE|MC)|(MULTICHOICE_V|MCV)|(MULTICHOICE_H|MCH)|' .
 375          '(SHORTANSWER|SA|MW)|(SHORTANSWER_C|SAC|MWC)|' .
 376          '(MULTICHOICE_S|MCS)|(MULTICHOICE_VS|MCVS)|(MULTICHOICE_HS|MCHS)|'.
 377          '(MULTIRESPONSE|MR)|(MULTIRESPONSE_H|MRH)|(MULTIRESPONSE_S|MRS)|(MULTIRESPONSE_HS|MRHS)');
 378  define('ANSWER_START_REGEX',
 379         '\{([0-9]*):(' . ANSWER_TYPE_DEF_REGEX . '):');
 380  
 381  define('ANSWER_REGEX',
 382          ANSWER_START_REGEX
 383          . '(' . ANSWER_ALTERNATIVE_REGEX
 384          . '(~'
 385          . ANSWER_ALTERNATIVE_REGEX
 386          . ')*)\}');
 387  
 388  // Parenthesis positions for singulars in ANSWER_REGEX.
 389  define('ANSWER_REGEX_NORM', 1);
 390  define('ANSWER_REGEX_ANSWER_TYPE_NUMERICAL', 3);
 391  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE', 4);
 392  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_REGULAR', 5);
 393  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_HORIZONTAL', 6);
 394  define('ANSWER_REGEX_ANSWER_TYPE_SHORTANSWER', 7);
 395  define('ANSWER_REGEX_ANSWER_TYPE_SHORTANSWER_C', 8);
 396  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_SHUFFLED', 9);
 397  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_REGULAR_SHUFFLED', 10);
 398  define('ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_HORIZONTAL_SHUFFLED', 11);
 399  define('ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE', 12);
 400  define('ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_HORIZONTAL', 13);
 401  define('ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_SHUFFLED', 14);
 402  define('ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_HORIZONTAL_SHUFFLED', 15);
 403  define('ANSWER_REGEX_ALTERNATIVES', 16);
 404  
 405  /**
 406   * Initialise subquestion fields that are constant across all MULTICHOICE
 407   * types.
 408   *
 409   * @param objet $wrapped  The subquestion to initialise
 410   *
 411   */
 412  function qtype_multianswer_initialise_multichoice_subquestion($wrapped) {
 413      $wrapped->qtype = 'multichoice';
 414      $wrapped->single = 1;
 415      $wrapped->answernumbering = 0;
 416      $wrapped->correctfeedback['text'] = '';
 417      $wrapped->correctfeedback['format'] = FORMAT_HTML;
 418      $wrapped->correctfeedback['itemid'] = '';
 419      $wrapped->partiallycorrectfeedback['text'] = '';
 420      $wrapped->partiallycorrectfeedback['format'] = FORMAT_HTML;
 421      $wrapped->partiallycorrectfeedback['itemid'] = '';
 422      $wrapped->incorrectfeedback['text'] = '';
 423      $wrapped->incorrectfeedback['format'] = FORMAT_HTML;
 424      $wrapped->incorrectfeedback['itemid'] = '';
 425  }
 426  
 427  function qtype_multianswer_extract_question($text) {
 428      // Variable $text is an array [text][format][itemid].
 429      $question = new stdClass();
 430      $question->qtype = 'multianswer';
 431      $question->questiontext = $text;
 432      $question->generalfeedback['text'] = '';
 433      $question->generalfeedback['format'] = FORMAT_HTML;
 434      $question->generalfeedback['itemid'] = '';
 435  
 436      $question->options = new stdClass();
 437      $question->options->questions = array();
 438      $question->defaultmark = 0; // Will be increased for each answer norm.
 439  
 440      for ($positionkey = 1;
 441              preg_match('/'.ANSWER_REGEX.'/s', $question->questiontext['text'], $answerregs);
 442              ++$positionkey) {
 443          $wrapped = new stdClass();
 444          $wrapped->generalfeedback['text'] = '';
 445          $wrapped->generalfeedback['format'] = FORMAT_HTML;
 446          $wrapped->generalfeedback['itemid'] = '';
 447          if (isset($answerregs[ANSWER_REGEX_NORM]) && $answerregs[ANSWER_REGEX_NORM] !== '') {
 448              $wrapped->defaultmark = $answerregs[ANSWER_REGEX_NORM];
 449          } else {
 450              $wrapped->defaultmark = '1';
 451          }
 452          if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_NUMERICAL])) {
 453              $wrapped->qtype = 'numerical';
 454              $wrapped->multiplier = array();
 455              $wrapped->units      = array();
 456              $wrapped->instructions['text'] = '';
 457              $wrapped->instructions['format'] = FORMAT_HTML;
 458              $wrapped->instructions['itemid'] = '';
 459          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_SHORTANSWER])) {
 460              $wrapped->qtype = 'shortanswer';
 461              $wrapped->usecase = 0;
 462          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_SHORTANSWER_C])) {
 463              $wrapped->qtype = 'shortanswer';
 464              $wrapped->usecase = 1;
 465          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE])) {
 466              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 467              $wrapped->shuffleanswers = 0;
 468              $wrapped->layout = qtype_multichoice_base::LAYOUT_DROPDOWN;
 469          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_SHUFFLED])) {
 470              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 471              $wrapped->shuffleanswers = 1;
 472              $wrapped->layout = qtype_multichoice_base::LAYOUT_DROPDOWN;
 473          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_REGULAR])) {
 474              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 475              $wrapped->shuffleanswers = 0;
 476              $wrapped->layout = qtype_multichoice_base::LAYOUT_VERTICAL;
 477          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_REGULAR_SHUFFLED])) {
 478              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 479              $wrapped->shuffleanswers = 1;
 480              $wrapped->layout = qtype_multichoice_base::LAYOUT_VERTICAL;
 481          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_HORIZONTAL])) {
 482              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 483              $wrapped->shuffleanswers = 0;
 484              $wrapped->layout = qtype_multichoice_base::LAYOUT_HORIZONTAL;
 485          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTICHOICE_HORIZONTAL_SHUFFLED])) {
 486              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 487              $wrapped->shuffleanswers = 1;
 488              $wrapped->layout = qtype_multichoice_base::LAYOUT_HORIZONTAL;
 489          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE])) {
 490              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 491              $wrapped->single = 0;
 492              $wrapped->shuffleanswers = 0;
 493              $wrapped->layout = qtype_multichoice_base::LAYOUT_VERTICAL;
 494          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_HORIZONTAL])) {
 495              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 496              $wrapped->single = 0;
 497              $wrapped->shuffleanswers = 0;
 498              $wrapped->layout = qtype_multichoice_base::LAYOUT_HORIZONTAL;
 499          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_SHUFFLED])) {
 500              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 501              $wrapped->single = 0;
 502              $wrapped->shuffleanswers = 1;
 503              $wrapped->layout = qtype_multichoice_base::LAYOUT_VERTICAL;
 504          } else if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_MULTIRESPONSE_HORIZONTAL_SHUFFLED])) {
 505              qtype_multianswer_initialise_multichoice_subquestion($wrapped);
 506              $wrapped->single = 0;
 507              $wrapped->shuffleanswers = 1;
 508              $wrapped->layout = qtype_multichoice_base::LAYOUT_HORIZONTAL;
 509          } else {
 510              throw new \moodle_exception('unknownquestiontype', 'question', '', $answerregs[2]);
 511              return false;
 512          }
 513  
 514          // Each $wrapped simulates a $form that can be processed by the
 515          // respective save_question and save_question_options methods of the
 516          // wrapped questiontypes.
 517          $wrapped->answer   = array();
 518          $wrapped->fraction = array();
 519          $wrapped->feedback = array();
 520          $wrapped->questiontext['text'] = $answerregs[0];
 521          $wrapped->questiontext['format'] = FORMAT_HTML;
 522          $wrapped->questiontext['itemid'] = '';
 523          $answerindex = 0;
 524  
 525          $hasspecificfraction = false;
 526          $remainingalts = $answerregs[ANSWER_REGEX_ALTERNATIVES];
 527          while (preg_match('/~?'.ANSWER_ALTERNATIVE_REGEX.'/s', $remainingalts, $altregs)) {
 528              if ('=' == $altregs[ANSWER_ALTERNATIVE_REGEX_FRACTION]) {
 529                  $wrapped->fraction["{$answerindex}"] = '1';
 530              } else if ($percentile = $altregs[ANSWER_ALTERNATIVE_REGEX_PERCENTILE_FRACTION]) {
 531                  // Accept either decimal place character.
 532                  $wrapped->fraction["{$answerindex}"] = .01 * str_replace(',', '.', $percentile);
 533                  $hasspecificfraction = true;
 534              } else {
 535                  $wrapped->fraction["{$answerindex}"] = '0';
 536              }
 537              if (isset($altregs[ANSWER_ALTERNATIVE_REGEX_FEEDBACK])) {
 538                  $feedback = html_entity_decode(
 539                          $altregs[ANSWER_ALTERNATIVE_REGEX_FEEDBACK], ENT_QUOTES, 'UTF-8');
 540                  $feedback = str_replace('\}', '}', $feedback);
 541                  $wrapped->feedback["{$answerindex}"]['text'] = str_replace('\#', '#', $feedback);
 542                  $wrapped->feedback["{$answerindex}"]['format'] = FORMAT_HTML;
 543                  $wrapped->feedback["{$answerindex}"]['itemid'] = '';
 544              } else {
 545                  $wrapped->feedback["{$answerindex}"]['text'] = '';
 546                  $wrapped->feedback["{$answerindex}"]['format'] = FORMAT_HTML;
 547                  $wrapped->feedback["{$answerindex}"]['itemid'] = '';
 548  
 549              }
 550              if (!empty($answerregs[ANSWER_REGEX_ANSWER_TYPE_NUMERICAL])
 551                      && preg_match('~'.NUMERICAL_ALTERNATIVE_REGEX.'~s',
 552                              $altregs[ANSWER_ALTERNATIVE_REGEX_ANSWER], $numregs)) {
 553                  $wrapped->answer[] = $numregs[NUMERICAL_CORRECT_ANSWER];
 554                  if (array_key_exists(NUMERICAL_ABS_ERROR_MARGIN, $numregs)) {
 555                      $wrapped->tolerance["{$answerindex}"] =
 556                      $numregs[NUMERICAL_ABS_ERROR_MARGIN];
 557                  } else {
 558                      $wrapped->tolerance["{$answerindex}"] = 0;
 559                  }
 560              } else { // Tolerance can stay undefined for non numerical questions.
 561                  // Undo quoting done by the HTML editor.
 562                  $answer = html_entity_decode(
 563                          $altregs[ANSWER_ALTERNATIVE_REGEX_ANSWER], ENT_QUOTES, 'UTF-8');
 564                  $answer = str_replace('\}', '}', $answer);
 565                  $wrapped->answer["{$answerindex}"] = str_replace('\#', '#', $answer);
 566                  if ($wrapped->qtype == 'multichoice') {
 567                      $wrapped->answer["{$answerindex}"] = array(
 568                              'text' => $wrapped->answer["{$answerindex}"],
 569                              'format' => FORMAT_HTML,
 570                              'itemid' => '');
 571                  }
 572              }
 573              $tmp = explode($altregs[0], $remainingalts, 2);
 574              $remainingalts = $tmp[1];
 575              $answerindex++;
 576          }
 577  
 578          // Fix the score for multichoice_multi questions (as positive scores should add up to 1, not have a maximum of 1).
 579          if (isset($wrapped->single) && $wrapped->single == 0) {
 580              $total = 0;
 581              foreach ($wrapped->fraction as $idx => $fraction) {
 582                  if ($fraction > 0) {
 583                      $total += $fraction;
 584                  }
 585              }
 586              if ($total) {
 587                  foreach ($wrapped->fraction as $idx => $fraction) {
 588                      if ($fraction > 0) {
 589                          $wrapped->fraction[$idx] = $fraction / $total;
 590                      } else if (!$hasspecificfraction) {
 591                          // If no specific fractions are given, set incorrect answers to each cancel out one correct answer.
 592                          $wrapped->fraction[$idx] = -(1.0 / $total);
 593                      }
 594                  }
 595              }
 596          }
 597  
 598          $question->defaultmark += $wrapped->defaultmark;
 599          $question->options->questions[$positionkey] = clone($wrapped);
 600          $question->questiontext['text'] = implode("{#$positionkey}",
 601                      explode($answerregs[0], $question->questiontext['text'], 2));
 602      }
 603      return $question;
 604  }
 605  
 606  /**
 607   * Validate a multianswer question.
 608   *
 609   * @param object $question  The multianswer question to validate as returned by qtype_multianswer_extract_question
 610   * @return array Array of error messages with questions field names as keys.
 611   */
 612  function qtype_multianswer_validate_question(stdClass $question) : array {
 613      $errors = array();
 614      if (!isset($question->options->questions)) {
 615          $errors['questiontext'] = get_string('questionsmissing', 'qtype_multianswer');
 616      } else {
 617          $subquestions = fullclone($question->options->questions);
 618          if (count($subquestions)) {
 619              $sub = 1;
 620              foreach ($subquestions as $subquestion) {
 621                  $prefix = 'sub_'.$sub.'_';
 622                  $answercount = 0;
 623                  $maxgrade = false;
 624                  $maxfraction = -1;
 625  
 626                  foreach ($subquestion->answer as $key => $answer) {
 627                      if (is_array($answer)) {
 628                          $answer = $answer['text'];
 629                      }
 630                      $trimmedanswer = trim($answer);
 631                      if ($trimmedanswer !== '') {
 632                          $answercount++;
 633                          if ($subquestion->qtype == 'numerical' &&
 634                                  !(qtype_numerical::is_valid_number($trimmedanswer) || $trimmedanswer == '*')) {
 635                              $errors[$prefix.'answer['.$key.']'] =
 636                                      get_string('answermustbenumberorstar', 'qtype_numerical');
 637                          }
 638                          if ($subquestion->fraction[$key] == 1) {
 639                              $maxgrade = true;
 640                          }
 641                          if ($subquestion->fraction[$key] > $maxfraction) {
 642                              $maxfraction = $subquestion->fraction[$key];
 643                          }
 644                          // For 'multiresponse' we are OK if there is at least one fraction > 0.
 645                          if ($subquestion->qtype == 'multichoice' && $subquestion->single == 0 &&
 646                              $subquestion->fraction[$key] > 0) {
 647                              $maxgrade = true;
 648                          }
 649                      }
 650                  }
 651                  if ($subquestion->qtype == 'multichoice' && $answercount < 2) {
 652                      $errors[$prefix.'answer[0]'] = get_string('notenoughanswers', 'qtype_multichoice', 2);
 653                  } else if ($answercount == 0) {
 654                      $errors[$prefix.'answer[0]'] = get_string('notenoughanswers', 'question', 1);
 655                  }
 656                  if ($maxgrade == false) {
 657                      $errors[$prefix.'fraction[0]'] = get_string('fractionsnomax', 'question');
 658                  }
 659                  $sub++;
 660              }
 661          } else {
 662              $errors['questiontext'] = get_string('questionsmissing', 'qtype_multianswer');
 663          }
 664      }
 665      return $errors;
 666  }