MDL-32188 quiz/question: behaviours can add to the review summary.
[moodle.git] / question / type / questionbase.php
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d1b7e03d 1<?php
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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//
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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
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17/**
18 * This file defines the class {@link question_definition} and its subclasses.
19 *
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20 * The type hierarchy is quite complex. Here is a summary:
21 * - question_definition
22 * - question_information_item
23 * - question_with_responses implements question_manually_gradable
24 * - question_graded_automatically implements question_automatically_gradable
25 * - question_graded_automatically_with_countback implements question_automatically_gradable_with_countback
26 * - question_graded_by_strategy
27 *
28 * Other classes:
29 * - question_classified_response
30 * - question_answer
31 * - question_hint
32 * - question_hint_with_parts
33 * - question_first_matching_answer_grading_strategy implements question_grading_strategy
34 *
35 * Other interfaces:
36 * - question_response_answer_comparer
37 *
b04a4319 38 * @package moodlecore
d1b7e03d 39 * @subpackage questiontypes
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40 * @copyright 2009 The Open University
41 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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42 */
43
44
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45defined('MOODLE_INTERNAL') || die();
46
47
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48/**
49 * The definition of a question of a particular type.
50 *
51 * This class is a close match to the question table in the database.
52 * Definitions of question of a particular type normally subclass one of the
53 * more specific classes {@link question_with_responses},
54 * {@link question_graded_automatically} or {@link question_information_item}.
55 *
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56 * @copyright 2009 The Open University
57 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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58 */
59abstract class question_definition {
60 /** @var integer id of the question in the datase, or null if this question
61 * is not in the database. */
62 public $id;
63
64 /** @var integer question category id. */
65 public $category;
66
e35ba43c 67 /** @var integer question context id. */
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68 public $contextid;
69
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70 /** @var integer parent question id. */
71 public $parent = 0;
72
73 /** @var question_type the question type this question is. */
74 public $qtype;
75
76 /** @var string question name. */
77 public $name;
78
79 /** @var string question text. */
80 public $questiontext;
81
82 /** @var integer question test format. */
83 public $questiontextformat;
84
85 /** @var string question general feedback. */
86 public $generalfeedback;
87
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88 /** @var integer question test format. */
89 public $generalfeedbackformat;
90
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91 /** @var number what this quetsion is marked out of, by default. */
92 public $defaultmark = 1;
93
94 /** @var integer How many question numbers this question consumes. */
95 public $length = 1;
96
97 /** @var number penalty factor of this question. */
98 public $penalty = 0;
99
100 /** @var string unique identifier of this question. */
101 public $stamp;
102
103 /** @var string unique identifier of this version of this question. */
104 public $version;
105
106 /** @var boolean whethre this question has been deleted/hidden in the question bank. */
107 public $hidden = 0;
108
109 /** @var integer timestamp when this question was created. */
110 public $timecreated;
111
112 /** @var integer timestamp when this question was modified. */
113 public $timemodified;
114
115 /** @var integer userid of the use who created this question. */
116 public $createdby;
117
118 /** @var integer userid of the use who modified this question. */
119 public $modifiedby;
120
121 /** @var array of question_hints. */
122 public $hints = array();
123
124 /**
125 * Constructor. Normally to get a question, you call
126 * {@link question_bank::load_question()}, but questions can be created
127 * directly, for example in unit test code.
128 * @return unknown_type
129 */
130 public function __construct() {
131 }
132
133 /**
134 * @return the name of the question type (for example multichoice) that this
135 * question is.
136 */
137 public function get_type_name() {
138 return $this->qtype->name();
139 }
140
141 /**
142 * Creat the appropriate behaviour for an attempt at this quetsion,
143 * given the desired (archetypal) behaviour.
144 *
145 * This default implementation will suit most normal graded questions.
146 *
147 * If your question is of a patricular type, then it may need to do something
148 * different. For example, if your question can only be graded manually, then
149 * it should probably return a manualgraded behaviour, irrespective of
150 * what is asked for.
151 *
152 * If your question wants to do somthing especially complicated is some situations,
153 * then you may wish to return a particular behaviour related to the
154 * one asked for. For example, you migth want to return a
155 * qbehaviour_interactive_adapted_for_myqtype.
156 *
157 * @param question_attempt $qa the attempt we are creating an behaviour for.
158 * @param string $preferredbehaviour the requested type of behaviour.
159 * @return question_behaviour the new behaviour object.
160 */
161 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
162 return question_engine::make_archetypal_behaviour($preferredbehaviour, $qa);
163 }
164
165 /**
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166 * Start a new attempt at this question, storing any information that will
167 * be needed later in the step.
d1b7e03d 168 *
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169 * This is where the question can do any initialisation required on a
170 * per-attempt basis. For example, this is where the multiple choice
171 * question type randomly shuffles the choices (if that option is set).
d1b7e03d 172 *
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173 * Any information about how the question has been set up for this attempt
174 * should be stored in the $step, by calling $step->set_qt_var(...).
175 *
176 * @param question_attempt_step The first step of the {@link question_attempt}
177 * being started. Can be used to store state.
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178 * @param int $varant which variant of this question to start. Will be between
179 * 1 and {@link get_num_variants()} inclusive.
ef31a283 180 */
1da821bb 181 public function start_attempt(question_attempt_step $step, $variant) {
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182 }
183
184 /**
185 * When an in-progress {@link question_attempt} is re-loaded from the
186 * database, this method is called so that the question can re-initialise
187 * its internal state as needed by this attempt.
188 *
189 * For example, the multiple choice question type needs to set the order
190 * of the choices to the order that was set up when start_attempt was called
191 * originally. All the information required to do this should be in the
192 * $step object, which is the first step of the question_attempt being loaded.
193 *
194 * @param question_attempt_step The first step of the {@link question_attempt}
195 * being loaded.
d1b7e03d 196 */
ef31a283 197 public function apply_attempt_state(question_attempt_step $step) {
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198 }
199
200 /**
201 * Generate a brief, plain-text, summary of this question. This is used by
202 * various reports. This should show the particular variant of the question
203 * as presented to students. For example, the calculated quetsion type would
204 * fill in the particular numbers that were presented to the student.
205 * This method will return null if such a summary is not possible, or
206 * inappropriate.
207 * @return string|null a plain text summary of this question.
208 */
ec3d4ef5 209 public function get_question_summary() {
22cebed5 210 return $this->html_to_text($this->questiontext, $this->questiontextformat);
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211 }
212
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213 /**
214 * @return int the number of vaiants that this question has.
215 */
216 public function get_num_variants() {
217 return 1;
218 }
219
220 /**
221 * @return string that can be used to seed the pseudo-random selection of a
222 * variant.
223 */
224 public function get_variants_selection_seed() {
225 return $this->stamp;
226 }
227
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228 /**
229 * Some questions can return a negative mark if the student gets it wrong.
230 *
231 * This method returns the lowest mark the question can return, on the
232 * fraction scale. that is, where the maximum possible mark is 1.0.
233 *
234 * @return number minimum fraction this question will ever return.
235 */
236 public function get_min_fraction() {
237 return 0;
238 }
239
240 /**
241 * Given a response, rest the parts that are wrong.
242 * @param array $response a response
243 * @return array a cleaned up response with the wrong bits reset.
244 */
245 public function clear_wrong_from_response(array $response) {
246 return array();
247 }
248
249 /**
250 * Return the number of subparts of this response that are right.
251 * @param array $response a response
252 * @return array with two elements, the number of correct subparts, and
253 * the total number of subparts.
254 */
255 public function get_num_parts_right(array $response) {
256 return array(null, null);
257 }
258
259 /**
b36d2d06 260 * @param moodle_page the page we are outputting to.
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261 * @return qtype_renderer the renderer to use for outputting this question.
262 */
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263 public function get_renderer(moodle_page $page) {
264 return $page->get_renderer($this->qtype->plugin_name());
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265 }
266
267 /**
268 * What data may be included in the form submission when a student submits
269 * this question in its current state?
270 *
271 * This information is used in calls to optional_param. The parameter name
272 * has {@link question_attempt::get_field_prefix()} automatically prepended.
273 *
274 * @return array|string variable name => PARAM_... constant, or, as a special case
275 * that should only be used in unavoidable, the constant question_attempt::USE_RAW_DATA
276 * meaning take all the raw submitted data belonging to this question.
277 */
278 public abstract function get_expected_data();
279
280 /**
281 * What data would need to be submitted to get this question correct.
282 * If there is more than one correct answer, this method should just
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283 * return one possibility. If it is not possible to compute a correct
284 * response, this method should return null.
d1b7e03d 285 *
da22c012 286 * @return array|null parameter name => value.
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287 */
288 public abstract function get_correct_response();
289
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290
291 /**
292 * Passed an array of data representing a student response this function transforms the array to a response array as would be
293 * returned from the html form for this question instance.
294 *
295 * In most cases the array will just be returned as is. Some question types will need to transform the keys of the array in
296 * as the meaning of the keys in the html form is deliberately obfuscated so that someone looking at the html does not get an
297 * advantage.
298 *
299 * @param array $simulatedresponse an array of data representing a student response
300 * @return array a response array as would be returned from the html form (but without prefixes)
301 */
302 public function prepare_simulated_post_data($simulatedresponse) {
303 return $simulatedresponse;
304 }
305
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306 /**
307 * Apply {@link format_text()} to some content with appropriate settings for
308 * this question.
309 *
310 * @param string $text some content that needs to be output.
22cebed5 311 * @param int $format the FORMAT_... constant.
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312 * @param question_attempt $qa the question attempt.
313 * @param string $component used for rewriting file area URLs.
314 * @param string $filearea used for rewriting file area URLs.
f7970e3c 315 * @param bool $clean Whether the HTML needs to be cleaned. Generally,
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316 * parts of the question do not need to be cleaned, and student input does.
317 * @return string the text formatted for output by format_text.
318 */
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319 public function format_text($text, $format, $qa, $component, $filearea, $itemid,
320 $clean = false) {
0ff4bd08 321 $formatoptions = new stdClass();
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322 $formatoptions->noclean = !$clean;
323 $formatoptions->para = false;
7a719748 324 $text = $qa->rewrite_pluginfile_urls($text, $component, $filearea, $itemid);
22cebed5 325 return format_text($text, $format, $formatoptions);
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326 }
327
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328 /**
329 * Convert some part of the question text to plain text. This might be used,
330 * for example, by get_response_summary().
331 * @param string $text The HTML to reduce to plain text.
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332 * @param int $format the FORMAT_... constant.
333 * @return string the equivalent plain text.
ec3d4ef5 334 */
22cebed5 335 public function html_to_text($text, $format) {
e2b388c1 336 return question_utils::to_plain_text($text, $format);
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337 }
338
d1b7e03d 339 /** @return the result of applying {@link format_text()} to the question text. */
2b7da645 340 public function format_questiontext($qa) {
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341 return $this->format_text($this->questiontext, $this->questiontextformat,
342 $qa, 'question', 'questiontext', $this->id);
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343 }
344
345 /** @return the result of applying {@link format_text()} to the general feedback. */
2b7da645 346 public function format_generalfeedback($qa) {
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347 return $this->format_text($this->generalfeedback, $this->generalfeedbackformat,
348 $qa, 'question', 'generalfeedback', $this->id);
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349 }
350
351 /**
352 * Checks whether the users is allow to be served a particular file.
93cadb1e 353 * @param question_attempt $qa the question attempt being displayed.
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354 * @param question_display_options $options the options that control display of the question.
355 * @param string $component the name of the component we are serving files for.
356 * @param string $filearea the name of the file area.
357 * @param array $args the remaining bits of the file path.
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358 * @param bool $forcedownload whether the user must be forced to download the file.
359 * @return bool true if the user can access this file.
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360 */
361 public function check_file_access($qa, $options, $component, $filearea, $args, $forcedownload) {
362 if ($component == 'question' && $filearea == 'questiontext') {
363 // Question text always visible.
364 return true;
365
366 } else if ($component == 'question' && $filearea == 'generalfeedback') {
367 return $options->generalfeedback;
368
369 } else {
370 // Unrecognised component or filearea.
371 return false;
372 }
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373 }
374}
375
376
377/**
378 * This class represents a 'question' that actually does not allow the student
379 * to respond, like the description 'question' type.
380 *
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381 * @copyright 2009 The Open University
382 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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383 */
384class question_information_item extends question_definition {
385 public function __construct() {
386 parent::__construct();
387 $this->defaultmark = 0;
388 $this->penalty = 0;
389 $this->length = 0;
390 }
391
392 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
f3460297 393 return question_engine::make_behaviour('informationitem', $qa, $preferredbehaviour);
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394 }
395
396 public function get_expected_data() {
397 return array();
398 }
399
400 public function get_correct_response() {
401 return array();
402 }
403
404 public function get_question_summary() {
405 return null;
406 }
407}
408
409
410/**
411 * Interface that a {@link question_definition} must implement to be usable by
412 * the manual graded behaviour.
413 *
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414 * @copyright 2009 The Open University
415 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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416 */
417interface question_manually_gradable {
418 /**
419 * Used by many of the behaviours, to work out whether the student's
420 * response to the question is complete. That is, whether the question attempt
421 * should move to the COMPLETE or INCOMPLETE state.
422 *
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423 * @param array $response responses, as returned by
424 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 425 * @return bool whether this response is a complete answer to this question.
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426 */
427 public function is_complete_response(array $response);
428
429 /**
430 * Use by many of the behaviours to determine whether the student's
431 * response has changed. This is normally used to determine that a new set
432 * of responses can safely be discarded.
433 *
434 * @param array $prevresponse the responses previously recorded for this question,
435 * as returned by {@link question_attempt_step::get_qt_data()}
436 * @param array $newresponse the new responses, in the same format.
f7970e3c 437 * @return bool whether the two sets of responses are the same - that is
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438 * whether the new set of responses can safely be discarded.
439 */
440 public function is_same_response(array $prevresponse, array $newresponse);
441
442 /**
443 * Produce a plain text summary of a response.
444 * @param $response a response, as might be passed to {@link grade_response()}.
445 * @return string a plain text summary of that response, that could be used in reports.
446 */
447 public function summarise_response(array $response);
448
449 /**
450 * Categorise the student's response according to the categories defined by
451 * get_possible_responses.
452 * @param $response a response, as might be passed to {@link grade_response()}.
453 * @return array subpartid => {@link question_classified_response} objects.
454 * returns an empty array if no analysis is possible.
455 */
456 public function classify_response(array $response);
457}
458
459
460/**
461 * This class is used in the return value from
462 * {@link question_manually_gradable::classify_response()}.
463 *
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464 * @copyright 2010 The Open University
465 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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466 */
467class question_classified_response {
468 /**
469 * @var string the classification of this response the student gave to this
470 * part of the question. Must match one of the responseclasses returned by
471 * {@link question_type::get_possible_responses()}.
472 */
473 public $responseclassid;
474 /** @var string the actual response the student gave to this part. */
475 public $response;
476 /** @var number the fraction this part of the response earned. */
477 public $fraction;
478 /**
479 * Constructor, just an easy way to set the fields.
480 * @param string $responseclassid see the field descriptions above.
481 * @param string $response see the field descriptions above.
482 * @param number $fraction see the field descriptions above.
483 */
484 public function __construct($responseclassid, $response, $fraction) {
485 $this->responseclassid = $responseclassid;
486 $this->response = $response;
487 $this->fraction = $fraction;
488 }
489
490 public static function no_response() {
e5b0920e 491 return new question_classified_response(null, get_string('noresponse', 'question'), null);
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492 }
493}
494
495
496/**
497 * Interface that a {@link question_definition} must implement to be usable by
498 * the various automatic grading behaviours.
499 *
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500 * @copyright 2009 The Open University
501 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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502 */
503interface question_automatically_gradable extends question_manually_gradable {
504 /**
505 * Use by many of the behaviours to determine whether the student
506 * has provided enough of an answer for the question to be graded automatically,
507 * or whether it must be considered aborted.
508 *
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509 * @param array $response responses, as returned by
510 * {@link question_attempt_step::get_qt_data()}.
f7970e3c 511 * @return bool whether this response can be graded.
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512 */
513 public function is_gradable_response(array $response);
514
515 /**
516 * In situations where is_gradable_response() returns false, this method
517 * should generate a description of what the problem is.
518 * @return string the message.
519 */
520 public function get_validation_error(array $response);
521
522 /**
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523 * Grade a response to the question, returning a fraction between
524 * get_min_fraction() and 1.0, and the corresponding {@link question_state}
525 * right, partial or wrong.
526 * @param array $response responses, as returned by
527 * {@link question_attempt_step::get_qt_data()}.
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528 * @return array (number, integer) the fraction, and the state.
529 */
530 public function grade_response(array $response);
531
532 /**
533 * Get one of the question hints. The question_attempt is passed in case
534 * the question type wants to do something complex. For example, the
535 * multiple choice with multiple responses question type will turn off most
536 * of the hint options if the student has selected too many opitions.
f7970e3c 537 * @param int $hintnumber Which hint to display. Indexed starting from 0
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538 * @param question_attempt $qa The question_attempt.
539 */
540 public function get_hint($hintnumber, question_attempt $qa);
541
542 /**
543 * Generate a brief, plain-text, summary of the correct answer to this question.
544 * This is used by various reports, and can also be useful when testing.
545 * This method will return null if such a summary is not possible, or
546 * inappropriate.
547 * @return string|null a plain text summary of the right answer to this question.
548 */
549 public function get_right_answer_summary();
550}
551
552
553/**
554 * Interface that a {@link question_definition} must implement to be usable by
555 * the interactivecountback behaviour.
556 *
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557 * @copyright 2010 The Open University
558 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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559 */
560interface question_automatically_gradable_with_countback extends question_automatically_gradable {
561 /**
562 * Work out a final grade for this attempt, taking into account all the
563 * tries the student made.
564 * @param array $responses the response for each try. Each element of this
565 * array is a response array, as would be passed to {@link grade_response()}.
566 * There may be between 1 and $totaltries responses.
f7970e3c 567 * @param int $totaltries The maximum number of tries allowed.
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568 * @return numeric the fraction that should be awarded for this
569 * sequence of response.
570 */
571 public function compute_final_grade($responses, $totaltries);
572}
573
574
575/**
576 * This class represents a real question. That is, one that is not a
577 * {@link question_information_item}.
578 *
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579 * @copyright 2009 The Open University
580 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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581 */
582abstract class question_with_responses extends question_definition
583 implements question_manually_gradable {
c7df5006 584 public function classify_response(array $response) {
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585 return array();
586 }
587}
588
589
590/**
591 * This class represents a question that can be graded automatically.
592 *
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593 * @copyright 2009 The Open University
594 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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595 */
596abstract class question_graded_automatically extends question_with_responses
597 implements question_automatically_gradable {
598 /** @var Some question types have the option to show the number of sub-parts correct. */
599 public $shownumcorrect = false;
600
601 public function is_gradable_response(array $response) {
602 return $this->is_complete_response($response);
603 }
604
605 public function get_right_answer_summary() {
606 $correctresponse = $this->get_correct_response();
607 if (empty($correctresponse)) {
608 return null;
609 }
610 return $this->summarise_response($correctresponse);
611 }
612
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613 /**
614 * Check a request for access to a file belonging to a combined feedback field.
615 * @param question_attempt $qa the question attempt being displayed.
616 * @param question_display_options $options the options that control display of the question.
617 * @param string $filearea the name of the file area.
f7970e3c 618 * @return bool whether access to the file should be allowed.
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619 */
620 protected function check_combined_feedback_file_access($qa, $options, $filearea) {
621 $state = $qa->get_state();
622
623 if (!$state->is_finished()) {
624 $response = $qa->get_last_qt_data();
625 if (!$this->is_gradable_response($response)) {
626 return false;
627 }
628 list($notused, $state) = $this->grade_response($response);
629 }
630
631 return $options->feedback && $state->get_feedback_class() . 'feedback' == $filearea;
632 }
633
634 /**
635 * Check a request for access to a file belonging to a hint.
636 * @param question_attempt $qa the question attempt being displayed.
637 * @param question_display_options $options the options that control display of the question.
638 * @param array $args the remaining bits of the file path.
f7970e3c 639 * @return bool whether access to the file should be allowed.
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640 */
641 protected function check_hint_file_access($qa, $options, $args) {
642 if (!$options->feedback) {
643 return false;
644 }
645 $hint = $qa->get_applicable_hint();
3d9645ae 646 $hintid = reset($args); // Itemid is hint id.
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647 return $hintid == $hint->id;
648 }
649
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650 public function get_hint($hintnumber, question_attempt $qa) {
651 if (!isset($this->hints[$hintnumber])) {
652 return null;
653 }
654 return $this->hints[$hintnumber];
655 }
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656
657 public function format_hint(question_hint $hint, question_attempt $qa) {
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658 return $this->format_text($hint->hint, $hint->hintformat, $qa,
659 'question', 'hint', $hint->id);
7a719748 660 }
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661}
662
663
664/**
665 * This class represents a question that can be graded automatically with
666 * countback grading in interactive mode.
667 *
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668 * @copyright 2010 The Open University
669 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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670 */
671abstract class question_graded_automatically_with_countback
672 extends question_graded_automatically
673 implements question_automatically_gradable_with_countback {
674
675 public function make_behaviour(question_attempt $qa, $preferredbehaviour) {
676 if ($preferredbehaviour == 'interactive') {
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677 return question_engine::make_behaviour('interactivecountback',
678 $qa, $preferredbehaviour);
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679 }
680 return question_engine::make_archetypal_behaviour($preferredbehaviour, $qa);
681 }
682}
683
684
685/**
686 * This class represents a question that can be graded automatically by using
687 * a {@link question_grading_strategy}.
688 *
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689 * @copyright 2009 The Open University
690 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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691 */
692abstract class question_graded_by_strategy extends question_graded_automatically {
693 /** @var question_grading_strategy the strategy to use for grading. */
694 protected $gradingstrategy;
695
696 /** @param question_grading_strategy $strategy the strategy to use for grading. */
697 public function __construct(question_grading_strategy $strategy) {
698 parent::__construct();
699 $this->gradingstrategy = $strategy;
700 }
701
702 public function get_correct_response() {
703 $answer = $this->get_correct_answer();
704 if (!$answer) {
705 return array();
706 }
707
708 return array('answer' => $answer->answer);
709 }
710
711 /**
712 * Get an answer that contains the feedback and fraction that should be
713 * awarded for this resonse.
714 * @param array $response a response.
715 * @return question_answer the matching answer.
716 */
717 public function get_matching_answer(array $response) {
718 return $this->gradingstrategy->grade($response);
719 }
720
721 /**
722 * @return question_answer an answer that contains the a response that would
723 * get full marks.
724 */
725 public function get_correct_answer() {
726 return $this->gradingstrategy->get_correct_answer();
727 }
728
729 public function grade_response(array $response) {
730 $answer = $this->get_matching_answer($response);
731 if ($answer) {
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732 return array($answer->fraction,
733 question_state::graded_state_for_fraction($answer->fraction));
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734 } else {
735 return array(0, question_state::$gradedwrong);
736 }
737 }
738
739 public function classify_response(array $response) {
740 if (empty($response['answer'])) {
741 return array($this->id => question_classified_response::no_response());
742 }
743
744 $ans = $this->get_matching_answer($response);
745 if (!$ans) {
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746 return array($this->id => new question_classified_response(
747 0, $response['answer'], 0));
d1b7e03d 748 }
24400682 749
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750 return array($this->id => new question_classified_response(
751 $ans->id, $response['answer'], $ans->fraction));
752 }
753}
754
755
756/**
757 * Class to represent a question answer, loaded from the question_answers table
758 * in the database.
759 *
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760 * @copyright 2009 The Open University
761 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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762 */
763class question_answer {
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764 /** @var integer the answer id. */
765 public $id;
766
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767 /** @var string the answer. */
768 public $answer;
769
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770 /** @var integer one of the FORMAT_... constans. */
771 public $answerformat = FORMAT_PLAIN;
772
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773 /** @var number the fraction this answer is worth. */
774 public $fraction;
775
776 /** @var string the feedback for this answer. */
777 public $feedback;
778
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779 /** @var integer one of the FORMAT_... constans. */
780 public $feedbackformat;
781
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782 /**
783 * Constructor.
22cebed5 784 * @param int $id the answer.
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785 * @param string $answer the answer.
786 * @param number $fraction the fraction this answer is worth.
787 * @param string $feedback the feedback for this answer.
22cebed5 788 * @param int $feedbackformat the format of the feedback.
d1b7e03d 789 */
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790 public function __construct($id, $answer, $fraction, $feedback, $feedbackformat) {
791 $this->id = $id;
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792 $this->answer = $answer;
793 $this->fraction = $fraction;
794 $this->feedback = $feedback;
5f7cfba7 795 $this->feedbackformat = $feedbackformat;
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796 }
797}
798
799
800/**
801 * Class to represent a hint associated with a question.
802 * Used by iteractive mode, etc. A question has an array of these.
803 *
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804 * @copyright 2010 The Open University
805 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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806 */
807class question_hint {
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808 /** @var integer The hint id. */
809 public $id;
810 /** @var string The feedback hint to be shown. */
d1b7e03d 811 public $hint;
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812 /** @var integer The corresponding text FORMAT_... type. */
813 public $hintformat;
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814
815 /**
816 * Constructor.
f7970e3c 817 * @param int the hint id from the database.
d1b7e03d 818 * @param string $hint The hint text
f7970e3c 819 * @param int the corresponding text FORMAT_... type.
d1b7e03d 820 */
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821 public function __construct($id, $hint, $hintformat) {
822 $this->id = $id;
d1b7e03d 823 $this->hint = $hint;
7a719748 824 $this->hintformat = $hintformat;
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825 }
826
827 /**
828 * Create a basic hint from a row loaded from the question_hints table in the database.
829 * @param object $row with $row->hint set.
830 * @return question_hint
831 */
832 public static function load_from_record($row) {
7a719748 833 return new question_hint($row->id, $row->hint, $row->hintformat);
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834 }
835
836 /**
837 * Adjust this display options according to the hint settings.
838 * @param question_display_options $options
839 */
840 public function adjust_display_options(question_display_options $options) {
841 // Do nothing.
842 }
843}
844
845
846/**
847 * An extension of {@link question_hint} for questions like match and multiple
848 * choice with multile answers, where there are options for whether to show the
849 * number of parts right at each stage, and to reset the wrong parts.
850 *
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851 * @copyright 2010 The Open University
852 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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853 */
854class question_hint_with_parts extends question_hint {
855 /** @var boolean option to show the number of sub-parts of the question that were right. */
856 public $shownumcorrect;
857
858 /** @var boolean option to clear the parts of the question that were wrong on retry. */
859 public $clearwrong;
860
861 /**
862 * Constructor.
f7970e3c 863 * @param int the hint id from the database.
d1b7e03d 864 * @param string $hint The hint text
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865 * @param int the corresponding text FORMAT_... type.
866 * @param bool $shownumcorrect whether the number of right parts should be shown
867 * @param bool $clearwrong whether the wrong parts should be reset.
d1b7e03d 868 */
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869 public function __construct($id, $hint, $hintformat, $shownumcorrect, $clearwrong) {
870 parent::__construct($id, $hint, $hintformat);
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871 $this->shownumcorrect = $shownumcorrect;
872 $this->clearwrong = $clearwrong;
873 }
874
875 /**
876 * Create a basic hint from a row loaded from the question_hints table in the database.
877 * @param object $row with $row->hint, ->shownumcorrect and ->clearwrong set.
878 * @return question_hint_with_parts
879 */
880 public static function load_from_record($row) {
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881 return new question_hint_with_parts($row->id, $row->hint, $row->hintformat,
882 $row->shownumcorrect, $row->clearwrong);
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883 }
884
885 public function adjust_display_options(question_display_options $options) {
886 parent::adjust_display_options($options);
887 if ($this->clearwrong) {
888 $options->clearwrong = true;
889 }
890 $options->numpartscorrect = $this->shownumcorrect;
891 }
892}
893
894
895/**
896 * This question_grading_strategy interface. Used to share grading code between
897 * questions that that subclass {@link question_graded_by_strategy}.
898 *
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899 * @copyright 2009 The Open University
900 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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901 */
902interface question_grading_strategy {
903 /**
904 * Return a question answer that describes the outcome (fraction and feeback)
905 * for a particular respons.
906 * @param array $response the response.
907 * @return question_answer the answer describing the outcome.
908 */
909 public function grade(array $response);
910
911 /**
912 * @return question_answer an answer that contains the a response that would
913 * get full marks.
914 */
915 public function get_correct_answer();
916}
917
918
919/**
920 * This interface defines the methods that a {@link question_definition} must
921 * implement if it is to be graded by the
922 * {@link question_first_matching_answer_grading_strategy}.
923 *
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924 * @copyright 2009 The Open University
925 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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926 */
927interface question_response_answer_comparer {
928 /** @return array of {@link question_answers}. */
929 public function get_answers();
930
931 /**
932 * @param array $response the response.
933 * @param question_answer $answer an answer.
f7970e3c 934 * @return bool whether the response matches the answer.
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935 */
936 public function compare_response_with_answer(array $response, question_answer $answer);
937}
938
939
940/**
941 * This grading strategy is used by question types like shortanswer an numerical.
942 * It gets a list of possible answers from the question, and returns the first one
943 * that matches the given response. It returns the first answer with fraction 1.0
944 * when asked for the correct answer.
945 *
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946 * @copyright 2009 The Open University
947 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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948 */
949class question_first_matching_answer_grading_strategy implements question_grading_strategy {
950 /**
951 * @var question_response_answer_comparer (presumably also a
952 * {@link question_definition}) the question we are doing the grading for.
953 */
954 protected $question;
955
956 /**
957 * @param question_response_answer_comparer $question (presumably also a
958 * {@link question_definition}) the question we are doing the grading for.
959 */
960 public function __construct(question_response_answer_comparer $question) {
961 $this->question = $question;
962 }
963
964 public function grade(array $response) {
965 foreach ($this->question->get_answers() as $aid => $answer) {
966 if ($this->question->compare_response_with_answer($response, $answer)) {
967 $answer->id = $aid;
968 return $answer;
969 }
970 }
971 return null;
972 }
973
974 public function get_correct_answer() {
975 foreach ($this->question->get_answers() as $answer) {
976 $state = question_state::graded_state_for_fraction($answer->fraction);
977 if ($state == question_state::$gradedright) {
978 return $answer;
979 }
980 }
981 return null;
982 }
01c898ec 983}