First try at making algebra combinable

1 files changed, 272 insertions, 0 deletions

diff --git a/combinable/combinable.php b/combinable/combinable.php
new file mode 100644
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--- /dev/null
+++ b/combinable/combinable.php
@@ -0,0 +1,272 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Defines the hooks necessary to make the algebra question type combinable
+ *
+ * @package   qtype_algebra
+ * @copyright  2019 Jean-Michel Vedrine
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->dirroot . '/question/type/algebra/parser.php');
+
+define('SYMB_QUESTION_NUMANS_START', 2);
+define('SYMB_QUESTION_NUMANS_ADD', 1);
+
+class qtype_combined_combinable_type_algebra extends qtype_combined_combinable_type_base {
+
+    protected $identifier = 'algebra';
+
+    protected function extra_question_properties() {
+        return array('answerprefix' => '', 'allowedfuncs' => array('all' => 1));
+    }
+
+    protected function extra_answer_properties() {
+        return array('fraction' => '1', 'feedback' => array('text' => '', 'format' => FORMAT_PLAIN));
+    }
+
+    public function subq_form_fragment_question_option_fields() {
+        return array('compareby' => null,
+                     'nchecks' => null,
+                     'disallow' => null,
+                     'allowedfuncs' => null);
+    }
+}
+
+
+class qtype_combined_combinable_algebra extends qtype_combined_combinable_text_entry {
+
+    /**
+     * @param moodleform      $combinedform
+     * @param MoodleQuickForm $mform
+     * @param                 $repeatenabled
+     * @return mixed
+     */
+    public function add_form_fragment(moodleform $combinedform, MoodleQuickForm $mform, $repeatenabled) {
+        global $CFG;
+        $mform->addElement('select', $this->form_field_name('compareby'), get_string('compareby', 'qtype_algebra'),
+                   array( "sage"  => get_string('comparesage', 'qtype_algebra'),
+                          "eval"  => get_string('compareeval', 'qtype_algebra'),
+                          "equiv" => get_string('compareequiv', 'qtype_algebra')
+                         ));
+        $mform->setDefault($this->form_field_name('compareby'), $CFG->qtype_algebra_method);
+        $chkarray = array(  '1',   '2',   '3',   '5',   '7',
+                          '10',  '20',  '30',  '50',  '70',
+                         '100', '200', '300', '500', '700', '1000');
+        $mform->addElement('select', $this->form_field_name('nchecks'), get_string('nchecks', 'qtype_algebra'),
+                            array_combine($chkarray, $chkarray));
+        $mform->setDefault($this->form_field_name('nchecks'), '10');
+        $mform->addElement('text', $this->form_field_name('tolerance'), get_string('tolerance', 'qtype_algebra'));
+        $mform->setType($this->form_field_name('tolerance'), PARAM_NUMBER);
+        $mform->setDefault($this->form_field_name('tolerance'), '0.001');
+        // Add an entry for a disallowed expression.
+        $mform->addElement('text', $this->form_field_name('disallow'), get_string('disallow', 'qtype_algebra'), array('size' => 55));
+        $mform->setType($this->form_field_name('disallow'), PARAM_RAW);
+        $varels = array();
+        $varels[] = $mform->createElement('text', $this->form_field_name('variable[0]'), get_string('variablename', 'qtype_algebra'), array('size' => 10));
+        $mform->setType($this->form_field_name('variable'), PARAM_RAW);
+        $varels[] = $mform->createElement('text', $this->form_field_name('varmin[0]'), get_string('varmin', 'qtype_algebra'), array('size' => 10));
+        $mform->setType($this->form_field_name('varmin'), PARAM_RAW);
+        $varels[] = $mform->createElement('text', $this->form_field_name('varmax[0]'), get_string('varmax', 'qtype_algebra'), array('size' => 10));
+        $mform->setType($this->form_field_name('varmax'), PARAM_RAW);
+        $mform->addGroup($varels, $this->form_field_name('variables'),
+                                                                        get_string('variable', 'qtype_algebra'), '', false);
+        $mform->setDefault($this->form_field_name('applydictionarycheck'), 1);
+        $answerel = array($mform->createElement('text',
+                                                $this->form_field_name('answer'),
+                                                get_string('answerx', 'qtype_algebra'),
+                                                array('size' => 57, 'class' => 'tweakcss')));
+
+        if ($this->questionrec !== null) {
+            $countanswers = count($this->questionrec->options->answers);
+        } else {
+            $countanswers = 0;
+        }
+
+        if ($repeatenabled) {
+            $defaultstartnumbers = SYMB_QUESTION_NUMANS_START;
+            $repeatsatstart = max($defaultstartnumbers, $countanswers + SYMB_QUESTION_NUMANS_ADD);
+        } else {
+            $repeatsatstart = $countanswers;
+        }
+
+        $combinedform->repeat_elements($answerel,
+                                        $repeatsatstart,
+                                        array(),
+                                        $this->form_field_name('noofchoices'),
+                                        $this->form_field_name('morechoices'),
+                                        SYMB_QUESTION_NUMANS_ADD,
+                                        get_string('addmoreanswerblanks', 'qtype_algebra'),
+                                        true);
+        $mform->setType($this->form_field_name('answer'), PARAM_RAW_TRIMMED);
+    }
+
+    public function data_to_form($context, $fileoptions) {
+        $answers = array('answer' => array());
+        if ($this->questionrec !== null) {
+            foreach ($this->questionrec->options->answers as $answer) {
+                $answers['answer'][] = $answer->answer;
+            }
+            $variable = array_pop($this->questionrec->options->variables);
+            $variables['variable'][] = $variable->name;
+            $variables['varmin'][] = $variable->min;
+            $variables['varmax'][] = $variable->max;
+        }
+        $data = parent::data_to_form($context, $fileoptions) + $answers + $variables;
+
+
+        return $data;
+    }
+
+
+    public function validate() {
+        $errors = array();
+        // Regular expression string to match a number.
+        $renumber = '/([+-]*(([0-9]+\.[0-9]*)|([0-9]+)|(\.[0-9]+))|'.
+            '(([0-9]+\.[0-9]*)|([0-9]+)|(\.[0-9]+))E([-+]?\d+))/A';
+
+        // Perform sanity checks on the variables.
+        $vars = $this->formdata->variable;;
+        // Create an array of defined variables.
+        $varlist = array();
+        foreach ($vars as $key => $var) {
+            $trimvar = trim($var);
+            $trimmin = trim($this->formdata->varmin[$key]);
+            $trimmax = trim($this->formdata->varmax[$key]);
+            // Check that there is a non empty variable name otherwise skip.
+            if ($trimvar == '') {
+                continue;
+            }
+            // Check that this variable does not have the same name as a function.
+            if (in_array($trimvar, qtype_algebra_parser::$functions) or in_array($trimvar, qtype_algebra_parser::$specials)) {
+                $errors[$this->form_field_name("variables")] = get_string('illegalvarname', 'qtype_algebra', $trimvar);
+            }
+            // Check that this variable has not been defined before.
+            if (in_array($trimvar, $varlist)) {
+                $errors[$this->form_field_name("variables")] = get_string('duplicatevar', 'qtype_algebra', $trimvar);
+            } else {
+                // Add the variable to the list of defined variables.
+                $varlist[] = $trimvar;
+            }
+            // If the comparison algorithm selected is evaluate then ensure that each variable
+            // has a valid minimum and maximum defined. For the other types of comparison we can
+            // ignore the range.
+            if ($this->formdata->compareby == 'eval') {
+                // Check that a minimum has been defined.
+                if ($trimmin == '') {
+                    $errors[$this->form_field_name("variables")] = get_string('novarmin', 'qtype_algebra');
+                } else if (!preg_match($renumber, $trimmin)) {
+                    // If there is one check that it's a number.
+                    $errors[$this->form_field_name("variables")] = get_string('notanumber', 'qtype_algebra');
+                }
+                if ($trimmax == '') {
+                    $errors[$this->form_field_name("variables")] = get_string('novarmax', 'qtype_algebra');
+                } else if (!preg_match($renumber, $trimmax)) {
+                    // If there is one check that it is a number.
+                    $errors[$this->form_field_name("variables")] = get_string('notanumber', 'qtype_algebra');
+                }
+                // Check that the minimum is less that the maximum!
+                if ((float)$trimmin > (float)$trimmax) {
+                    $errors[$this->form_field_name("variable")] = get_string('varmingtmax', 'qtype_algebra');
+                }
+            } // End check for eval type.
+        }     // End loop over variables.
+        // Check that at least one variable is defined.
+        if (count($varlist) == 0) {
+            $errors[$this->form_field_name('variables')] = get_string('notenoughvars', 'qtype_algebra');
+        }
+
+        // Now perform the sanity checks on the answers.
+        // Create a parser which we will use to check that the answers are understandable.
+        $p = new qtype_algebra_parser;
+        $answers = $this->formdata->answer;
+        $answercount = 0;
+        $maxgrade = false;
+        // Create an empty array to store the used variables.
+        $ansvars = array();
+        // Create an empty array to store the used functions.
+        $ansfuncs = array();
+        // Loop over all the answers in the form.
+        foreach ($answers as $key => $answer) {
+            // Try to parse the answer string using the parser. If this fails it will
+            // throw an exception which we catch to generate the associated error string
+            // for the expression.
+            try {
+                $expr = $p->parse($answer);
+                // Add any new variables to the list we are keeping. First we get the list
+                // of variables in this answer. Then we get the array of variables which are
+                // in this answer that are not in any previous answer (using array_diff).
+                // Finally we merge this difference array with the list of all variables so far.
+                $tmpvars = $expr->get_variables();
+                $ansvars = array_merge($ansvars, array_diff($tmpvars, $ansvars));
+                // Check that all the variables in this answer have been declared.
+                // Do this by looking for a non-empty array to be returned from the array_diff
+                // between the list of all declared variables and the variables in this answer.
+                if ($d = array_diff($tmpvars, $varlist)) {
+                    $errors[$this->form_field_name('answer['.$key.']')] = get_string('undefinedvar', 'qtype_algebra', "'".implode("', '", $d)."'");
+                }
+                // Do the same for functions which we did for variables.
+                $ansfuncs = array_merge($ansfuncs, array_diff($expr->get_functions(), $ansfuncs));
+                // Check that this is not an empty answer.
+                if (!is_a($expr, "qtype_algebra_parser_nullterm")) {
+                    // Increase the number of answers.
+                    $answercount++;
+                }
+            } catch (Exception $e) {
+                $errors[$this->form_field_name('answer['.$key.']')] = $e->getMessage();
+                // Return here because subsequent errors may be wrong due to not counting the answer
+                // which just failed to parse.
+                return $errors;
+            }
+        }
+        // Check that we have at least one answer.
+        if ($answercount == 0) {
+            $errors[$this->form_field_name('answer[0]')] = get_string('notenoughanswers', 'qtype_algebra');
+        }
+
+        // Check for variables which are defined but never used.
+        // Do this by looking for a non-empty array to be returned from array_diff.
+        if ($d = array_diff($varlist, $ansvars)) {
+            // Loop over all the variables in the form.
+            foreach ($vars as $key => $var) {
+                $trimvar = trim($var);
+                // If the variable is in the unused array then add the error message to that variable.
+                if (in_array($trimvar, $d)) {
+                    $errors[$this->form_field_name('variable['.$key.']')] = get_string('unusedvar', 'qtype_algebra');
+                }
+            }
+        }
+
+        // Check that the tolerance is greater than or equal to zero.
+        if ($this->formdata->tolerance < 0) {
+            $errors[$this->form_field_name('tolerance')] = get_string('toleranceltzero', 'qtype_algebra');
+        }
+
+
+        return $errors;
+    }
+
+    public function get_sup_sub_editor_option() {
+        return null;
+    }
+
+    public function has_submitted_data() {
+        return $this->submitted_data_array_not_empty('answer') || parent::has_submitted_data();
+    }
+}