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802f408f35
There are two well-known cases where the algebra filter messes up input that is obviously not meant for the algebra filter: 1. Copy and paste of unified diffs. 2. @@PLUGINFILE@@ tokens in the HTML that are due to be replaced by the files API. This fix detects these two cases, and just stops the algebra filter from replacing them.
250 lines
13 KiB
PHP
250 lines
13 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* Moodle - Filter for converting simple calculator-type algebraic
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* expressions to cached gif images
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*
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* @package filter
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* @subpackage algebra
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* @copyright 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu
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* Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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defined('MOODLE_INTERNAL') || die();
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//-------------------------------------------------------------------------
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// NOTE: This Moodle text filter converts algebraic expressions delimited
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// by either @@...@@ or by <algebra...>...</algebra> tags
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// first converts it to TeX using WeBWorK algebra parser Perl library
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// AlgParser.pm, part of the WeBWorK distribution obtained from
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// http://webhost.math.rochester.edu/downloadwebwork/
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// then converts the TeX to gif images using
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// mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by
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// John Forkosh john@forkosh.com. The mimetex.cgi ELF binary compiled for Linux i386
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// as well as AlgParser.pm are included with this distribution.
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// Note that there may be patent restrictions on the production of gif images
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// in Canada and some parts of Western Europe and Japan until July 2004.
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//-------------------------------------------------------------------------
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// You will then need to edit your moodle/config.php to invoke mathml_filter.php
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//-------------------------------------------------------------------------
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function filter_algebra_image($imagefile, $tex= "", $height="", $width="", $align="middle") {
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// Given the path to a picture file in a course, or a URL,
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// this function includes the picture in the page.
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global $CFG, $OUTPUT;
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$output = "";
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$style = 'style="border:0px; vertical-align:'.$align.';';
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$title = '';
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if ($tex) {
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$tex = html_entity_decode($tex, ENT_QUOTES, 'UTF-8');
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$title = 'title="'.s($tex).'"';
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}
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if ($height) {
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$style .= " height:{$height}px;";
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}
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if ($width) {
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$style .= " width:{$width}px;";
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}
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$style .= '"';
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$anchorcontents = '';
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if ($imagefile) {
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$anchorcontents .= "<img $title alt=\"".s($tex)."\" src=\"";
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if ($CFG->slasharguments) { // Use this method if possible for better caching
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$anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php/$imagefile";
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} else {
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$anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php?file=$imagefile";
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}
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$anchorcontents .= "\" $style />";
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if (!file_exists("$CFG->dataroot/filter/algebra/$imagefile") && has_capability('moodle/site:config', context_system::instance())) {
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$link = '/filter/algebra/algebradebug.php';
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$action = null;
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} else {
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$link = new moodle_url('/filter/tex/displaytex.php', array('texexp'=>$tex));
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$action = new popup_action('click', $link, 'popup', array('width'=>320,'height'=>240)); //TODO: the popups do not work when text caching is enabled!!
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}
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$output .= $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX'));
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} else {
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$output .= "Error: must pass URL or course";
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}
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return $output;
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}
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class filter_algebra extends moodle_text_filter {
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public function filter($text, array $options = array()){
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global $CFG, $DB;
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/// Do a quick check using stripos to avoid unnecessary wor
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if (!preg_match('/<algebra/i',$text) && !strstr($text,'@@')) {
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return $text;
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}
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//restrict filtering to forum 130 (Maths Tools on moodle.org)
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# $scriptname = $_SERVER['SCRIPT_NAME'];
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# if (!strstr($scriptname,'/forum/')) {
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# return $text;
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# }
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# if (strstr($scriptname,'post.php')) {
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# $parent = forum_get_post_full($_GET['reply']);
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# $discussion = $DB->get_record("forum_discussions",array("id"=>$parent->discussion));
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# } else if (strstr($scriptname,'discuss.php')) {
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# $discussion = $DB->get_record("forum_discussions",array("id"=>$_GET['d']));
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# } else {
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# return $text;
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# }
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# if ($discussion->forum != 130) {
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# return $text;
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# }
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preg_match_all('/@(@@+)([^@])/',$text,$matches);
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for ($i=0;$i<count($matches[0]);$i++) {
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$replacement = str_replace('@','@',$matches[1][$i]).$matches[2][$i];
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$text = str_replace($matches[0][$i],$replacement,$text);
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}
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// <algebra> some algebraic input expression </algebra>
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// or @@ some algebraic input expression @@
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preg_match_all('/<algebra>(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches);
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for ($i=0; $i<count($matches[0]); $i++) {
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$algebra = $matches[1][$i] . $matches[2][$i];
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// Look for some common false positives, and skip processing them.
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if ($algebra == 'PLUGINFILE' || $algebra == 'DRAFTFILE') {
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// Raw pluginfile URL.
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continue;
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}
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if (preg_match('/^ -\d+(,\d+)? \+\d+(,\d+)? $/', $algebra)) {
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// Part of a unified diff.
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continue;
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}
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$algebra = str_replace('<nolink>','',$algebra);
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$algebra = str_replace('</nolink>','',$algebra);
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$algebra = str_replace('<span class="nolink">','',$algebra);
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$algebra = str_replace('</span>','',$algebra);
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$align = "middle";
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if (preg_match('/^align=bottom /',$algebra)) {
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$align = "text-bottom";
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$algebra = preg_replace('/^align=bottom /','',$algebra);
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} else if (preg_match('/^align=top /',$algebra)) {
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$align = "text-top";
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$algebra = preg_replace('/^align=top /','',$algebra);
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}
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$md5 = md5($algebra);
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$filename = $md5 . ".gif";
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if (! $texcache = $DB->get_record("cache_filters",array("filter"=>"algebra", "md5key"=>$md5))) {
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$algebra = str_replace('<','<',$algebra);
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$algebra = str_replace('>','>',$algebra);
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$algebra = str_replace('<>','#',$algebra);
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$algebra = str_replace('<=','%',$algebra);
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$algebra = str_replace('>=','!',$algebra);
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$algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
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$algebra = str_replace('delta','zdelta',$algebra);
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$algebra = str_replace('beta','bita',$algebra);
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$algebra = str_replace('theta','thita',$algebra);
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$algebra = str_replace('zeta','zita',$algebra);
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$algebra = str_replace('eta','xeta',$algebra);
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$algebra = str_replace('epsilon','zepslon',$algebra);
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$algebra = str_replace('upsilon','zupslon',$algebra);
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$algebra = preg_replace('!\r\n?!',' ',$algebra);
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$algebra = escapeshellarg($algebra);
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if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) {
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$cmd = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
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} else {
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$cmd = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
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}
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$texexp = `$cmd`;
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if (preg_match('/parsehilight/',$texexp)) {
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$text = str_replace( $matches[0][$i],"<b>Syntax error:</b> " . $texexp,$text);
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} else if ($texexp) {
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$texexp = str_replace('zeroplace','',$texexp);
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$texexp = str_replace('#','\not= ',$texexp);
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$texexp = str_replace('%','\leq ',$texexp);
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$texexp = str_replace('!','\geq ',$texexp);
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$texexp = str_replace('\left{','{',$texexp);
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$texexp = str_replace('\right}','}',$texexp);
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$texexp = str_replace('\fun',' ',$texexp);
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$texexp = str_replace('infty','\infty',$texexp);
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$texexp = str_replace('alpha','\alpha',$texexp);
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$texexp = str_replace('gamma','\gamma',$texexp);
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$texexp = str_replace('iota','\iota',$texexp);
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$texexp = str_replace('kappa','\kappa',$texexp);
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$texexp = str_replace('lambda','\lambda',$texexp);
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$texexp = str_replace('mu','\mu',$texexp);
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$texexp = str_replace('nu','\nu',$texexp);
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$texexp = str_replace('xi','\xi',$texexp);
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$texexp = str_replace('rho','\rho',$texexp);
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$texexp = str_replace('sigma','\sigma',$texexp);
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$texexp = str_replace('tau','\tau',$texexp);
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$texexp = str_replace('phi','\phi',$texexp);
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$texexp = str_replace('chi','\chi',$texexp);
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$texexp = str_replace('psi','\psi',$texexp);
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$texexp = str_replace('omega','\omega',$texexp);
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$texexp = str_replace('zdelta','\delta',$texexp);
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$texexp = str_replace('bita','\beta',$texexp);
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$texexp = str_replace('thita','\theta',$texexp);
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$texexp = str_replace('zita','\zeta',$texexp);
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$texexp = str_replace('xeta','\eta',$texexp);
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$texexp = str_replace('zepslon','\epsilon',$texexp);
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$texexp = str_replace('zupslon','\upsilon',$texexp);
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$texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
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$texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
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$texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
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$texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
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$texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
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$texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
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$texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
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$texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
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$texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
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$texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
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$texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
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$texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
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$texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
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//$texexp = preg_replace('/\\\frac{(.+?)}{\\\left\((.+?)\\\right\)}/s','\frac{'."\$1}{\$2}",$texexp);
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$texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
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$texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
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$texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
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$texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
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$texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
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$texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
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$texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
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$texexp = str_replace('\mbox', '', $texexp); // now blacklisted in tex, sorry
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$texcache = new stdClass();
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$texcache->filter = 'algebra';
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$texcache->version = 1;
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$texcache->md5key = $md5;
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$texcache->rawtext = $texexp;
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$texcache->timemodified = time();
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$DB->insert_record("cache_filters", $texcache, false);
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$text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texexp, '', '', $align), $text);
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} else {
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$text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> ",$text);
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}
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} else {
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$text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texcache->rawtext), $text);
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}
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}
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return $text;
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}
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}
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