<?php
// This file is part of Stack - http://stack.maths.ed.ac.uk/
//
// Stack 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.
//
// Stack 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 Stack. If not, see <http://www.gnu.org/licenses/>.
defined('MOODLE_INTERNAL') || die();
require_once(__DIR__ . '/stack/mathsoutput/mathsoutput.class.php');
/**
* Base class for all the types of exception we throw.
*/
class stack_exception extends moodle_exception {
public function __construct($error) {
parent::__construct('exceptionmessage', 'qtype_stack', '', $error);
}
}
/**
* You need to call this method on the string you get from
* $castext->get_display_castext() before you echo it. This ensures that equations
* are displayed properly.
* @param string $castext the result of calling $castext->get_display_castext().
* @return string HTML ready to output.
*/
function stack_ouput_castext($castext) {
return format_text(stack_maths::process_display_castext($castext),
FORMAT_HTML, array('noclean' => true));
}
/**
* Equivalent to get_string($key, 'qtype_stack', $a), but this method ensure that
* any equations in the string are displayed properly.
* @param string $key the string name.
* @param mixed $a (optional) any values to interpolate into the string.
* @return string the language string
*/
function stack_string($key, $a = null) {
return stack_maths::process_lang_string(get_string($key, 'qtype_stack', $a));
}
/**
* Equivalent to get_string($key, 'qtype_stack', $a), but this method ensure that
* any equations in the string are displayed properly and that this message is formatted as an error.
* @param string $key the string name.
* @param mixed $a (optional) any values to interpolate into the string.
* @return string the language string
*/
function stack_string_error($key, $a = null) {
$key = stack_maths::process_lang_string(get_string($key, 'qtype_stack', $a));
return '<i class="icon fa fa-exclamation-circle text-danger fa-fw " title="' . $key . '" aria-label="' .
$key . '"></i>' . $key;
}
/**
* Private helper used by the next function.
*
* @return array search => replace strings.
*/
function get_stack_maxima_latex_replacements() {
// This is an array language code => replacements array.
static $replacements = [];
$lang = current_language();
if (!isset($replacements[$lang])) {
$replacements[$lang] = [
'QMCHAR' => '?',
'!LEFTSQ!' => '\left[',
'!LEFTR!' => '\left(',
'!RIGHTSQ!' => '\right]',
'!RIGHTR!' => '\right)',
'!ANDOR!' => stack_string('equiv_ANDOR'),
'!SAMEROOTS!' => stack_string('equiv_SAMEROOTS'),
'!MISSINGVAR!' => stack_string('equiv_MISSINGVAR'),
'!ASSUMEPOSVARS!' => stack_string('equiv_ASSUMEPOSVARS'),
'!ASSUMEPOSREALVARS!' => stack_string('equiv_ASSUMEPOSREALVARS'),
'!LET!' => stack_string('equiv_LET'),
'!AND!' => stack_string('equiv_AND'),
'!OR!' => stack_string('equiv_OR'),
'!NOT!' => stack_string('equiv_NOT'),
'!NAND!' => stack_string('equiv_NAND'),
'!NOR!' => stack_string('equiv_NOR'),
'!XOR!' => stack_string('equiv_XOR'),
'!XNOR!' => stack_string('equiv_XNOR'),
'!IMPLIES!' => stack_string('equiv_IMPLIES'),
'!BOOLTRUE!' => stack_string('true'),
'!BOOLFALSE!' => stack_string('false'),
];
}
return $replacements[$lang];
}
/**
* This function tidies up LaTeX from Maxima.
* @param string $rawfeedback
* @return string
*/
function stack_maxima_latex_tidy($latex) {
$replacements = get_stack_maxima_latex_replacements();
$latex = str_replace(array_keys($replacements), array_values($replacements), $latex);
// Also previously some spaces have been eliminated and line changes dropped.
// Apparently returning verbatim LaTeX was not a thing.
$latex = str_replace("\n ", '', $latex);
$latex = str_replace("\n", '', $latex);
// Just don't want to use regexp.
$latex = str_replace(' ', ' ', $latex);
$latex = str_replace(' ', ' ', $latex);
$latex = str_replace(' ', ' ', $latex);
return $latex;
}
/**
* This function takes a feedback string from Maxima and unpacks and translates it.
* @param string $rawfeedback
* @return string
*/
function stack_maxima_translate($rawfeedback) {
if (strpos($rawfeedback, 'stack_trans') === false) {
return trim(stack_maxima_latex_tidy($rawfeedback));
} else {
$rawfeedback = str_replace('[[', '', $rawfeedback);
$rawfeedback = str_replace(']]', '', $rawfeedback);
$rawfeedback = str_replace("\n", '', $rawfeedback);
$rawfeedback = str_replace('\n', '', $rawfeedback);
$rawfeedback = str_replace('!quot!', '"', $rawfeedback);
$translated = array();
preg_match_all('/stack_trans\(.*?\);/', $rawfeedback, $matches);
$feedback = $matches[0];
foreach ($feedback as $fb) {
$fb = substr($fb, 12, -2);
if (strstr($fb, "' , \"") === false) {
// We only have a feedback tag, with no optional arguments.
$translated[] = trim(stack_string(substr($fb, 1, -1)));
} else {
// We have a feedback tag and some optional arguments.
$tag = substr($fb, 1, strpos($fb, "' , \"") - 1);
$arg = substr($fb, strpos($fb, "' , \"") + 5, -2);
$args = explode('" , "', $arg);
$a = array();
for ($i = 0; $i < count($args); $i++) {
$a["m{$i}"] = $args[$i];
}
$translated[] = trim(stack_string($tag, $a));
}
}
return stack_maxima_latex_tidy(implode(' ', $translated));
}
}
function stack_maxima_format_casstring($str) {
// Santise the output, E.g. '>' -> '>'.
$str = stack_string_sanitise($str);
$str = str_replace('[[syntaxexamplehighlight]', '<span class="stacksyntaxexamplehighlight">', $str);
$str = str_replace('[syntaxexamplehighlight]]', '</span>', $str);
return html_writer::tag('span', $str, array('class' => 'stacksyntaxexample'));
}
function stack_string_sanitise($str) {
// Students may not input strings containing specific LaTeX
// i.e. no math-modes due to us being unable to decide if
// it is safe.
$str = str_replace('\\[', '\\​[', $str);
$str = str_replace('\\]', '\\​]', $str);
$str = str_replace('\\(', '\\​(', $str);
$str = str_replace('\\)', '\\​)', $str);
$str = str_replace('$$', '$​$', $str);
// Also any script tags need to be disabled.
$str = str_ireplace('<script', '<​script', $str);
$str = str_ireplace('</script>', '<​/script>', $str);
$str = str_ireplace('<iframe', '<​iframe', $str);
$str = str_ireplace('</iframe>', '<​/iframe>', $str);
$str = str_ireplace('<style', '<​style', $str);
$str = str_ireplace('</style>', '<​/style>', $str);
$str = str_ireplace('<div', '<​div', $str);
$str = str_ireplace('</div>', '<​/div>', $str);
$str = str_ireplace('/>', '/>', $str);
$str = str_ireplace('</', '</', $str);
$str = str_ireplace('<!--', '<!--', $str);
$str = str_ireplace('-->', '-->', $str);
$pat = array('/(on)([a-z]+[ ]*)(=)/', '/(href)([ ]*)(=)/', '/(src)([ ]*)(=)/');
$rep = array('on�$2�=', 'href�$2=', 'src�$2=');
$str = preg_replace($pat, $rep, $str);
return $str;
}
/**
* Used by the questiontest*.php scripts, and deploy.php, to do some initialisation
* that is needed on all of them.
* @return array page context, selected seed (or null), and URL parameters.
*/
function qtype_stack_setup_question_test_page($question) {
$seed = optional_param('seed', null, PARAM_INT);
$urlparams = array('questionid' => $question->id);
if (!is_null($seed) && $question->has_random_variants()) {
$urlparams['seed'] = $seed;
}
// Were we given a particular context to run the question in?
// This affects things like filter settings, or forced theme or language.
if ($cmid = optional_param('cmid', 0, PARAM_INT)) {
$cm = get_coursemodule_from_id(false, $cmid);
require_login($cm->course, false, $cm);
$context = context_module::instance($cmid);
$urlparams['cmid'] = $cmid;
} else if ($courseid = optional_param('courseid', 0, PARAM_INT)) {
require_login($courseid);
$context = context_course::instance($courseid);
$urlparams['courseid'] = $courseid;
} else {
$context = $question->get_context();
if ($context->contextlevel == CONTEXT_MODULE) {
$urlparams['cmid'] = $context->instanceid;
} else if ($context->contextlevel == CONTEXT_COURSE) {
$urlparams['courseid'] = $context->instanceid;
} else {
$urlparams['courseid'] = SITEID;
}
}
return array($context, $seed, $urlparams);
}
/* This class is needed to ignore requests for pluginfile rewrites in the bulk tester
* and possibly elsewhere, e.g. API.
*/
class stack_outofcontext_process {
public function __construct() {
}
/**
* Calls {@link question_rewrite_question_urls()} with appropriate parameters
* for content belonging to this question.
* @param string $text the content to output.
* @param string $component the component name (normally 'question' or 'qtype_...')
* @param string $filearea the name of the file area.
* @param int $itemid the item id.
* @return string the content with the URLs rewritten.
*/
public function rewrite_pluginfile_urls($text, $component, $filearea, $itemid) {
return $text;
}
}