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Developer Documentation
- Bug fixes for general core bugs in 4.0.x will end 8 May 2023 (12 months).
- Bug fixes for security issues in 4.0.x will end 13 November 2023 (18 months).
- PHP version: minimum PHP 7.3.0 Note: the minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is also supported.
/filter/algebra/ -> filter.php (source)
Differences Between: [Versions 310 and 400] [Versions 39 and 400]
1 <?php 2 3 // This file is part of Moodle - http://moodle.org/ 4 // 5 // Moodle is free software: you can redistribute it and/or modify 6 // it under the terms of the GNU General Public License as published by 7 // the Free Software Foundation, either version 3 of the License, or 8 // (at your option) any later version. 9 // 10 // Moodle is distributed in the hope that it will be useful, 11 // but WITHOUT ANY WARRANTY; without even the implied warranty of 12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 // GNU General Public License for more details. 14 // 15 // You should have received a copy of the GNU General Public License 16 // along with Moodle. If not, see <http://www.gnu.org/licenses/>. 17 18 /** 19 * Moodle - Filter for converting simple calculator-type algebraic 20 * expressions to cached gif images 21 * 22 * @package filter 23 * @subpackage algebra 24 * @copyright 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu 25 * Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca 26 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 27 */ 28 29 defined('MOODLE_INTERNAL') || die(); 30 31 //------------------------------------------------------------------------- 32 // NOTE: This Moodle text filter converts algebraic expressions delimited 33 // by either @@...@@ or by <algebra...>...</algebra> tags 34 // first converts it to TeX using WeBWorK algebra parser Perl library 35 // AlgParser.pm, part of the WeBWorK distribution obtained from 36 // http://webhost.math.rochester.edu/downloadwebwork/ 37 // then converts the TeX to gif images using 38 // mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by 39 // John Forkosh john@forkosh.com. The mimetex.cgi ELF binary compiled for Linux i386 40 // as well as AlgParser.pm are included with this distribution. 41 // Note that there may be patent restrictions on the production of gif images 42 // in Canada and some parts of Western Europe and Japan until July 2004. 43 //------------------------------------------------------------------------- 44 // You will then need to edit your moodle/config.php to invoke mathml_filter.php 45 //------------------------------------------------------------------------- 46 47 function filter_algebra_image($imagefile, $tex= "", $height="", $width="", $align="middle") { 48 // Given the path to a picture file in a course, or a URL, 49 // this function includes the picture in the page. 50 global $CFG, $OUTPUT; 51 52 $output = ""; 53 $style = 'style="border:0px; vertical-align:'.$align.';'; 54 $title = ''; 55 if ($tex) { 56 $tex = html_entity_decode($tex, ENT_QUOTES, 'UTF-8'); 57 $title = 'title="'.s($tex).'"'; 58 } 59 if ($height) { 60 $style .= " height:{$height}px;"; 61 } 62 if ($width) { 63 $style .= " width:{$width}px;"; 64 } 65 $style .= '"'; 66 $anchorcontents = ''; 67 if ($imagefile) { 68 $anchorcontents .= "<img $title alt=\"".s($tex)."\" src=\""; 69 if ($CFG->slasharguments) { // Use this method if possible for better caching 70 $anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php/$imagefile"; 71 } else { 72 $anchorcontents .= "$CFG->wwwroot/filter/algebra/pix.php?file=$imagefile"; 73 } 74 $anchorcontents .= "\" $style />"; 75 76 if (!file_exists("$CFG->dataroot/filter/algebra/$imagefile") && has_capability('moodle/site:config', context_system::instance())) { 77 $link = '/filter/algebra/algebradebug.php'; 78 $action = null; 79 } else { 80 $link = new moodle_url('/filter/tex/displaytex.php', array('texexp'=>$tex)); 81 $action = new popup_action('click', $link, 'popup', array('width'=>320,'height'=>240)); //TODO: the popups do not work when text caching is enabled!! 82 } 83 $output .= $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX')); 84 85 } else { 86 $output .= "Error: must pass URL or course"; 87 } 88 return $output; 89 } 90 91 class filter_algebra extends moodle_text_filter { 92 public function filter($text, array $options = array()){ 93 global $CFG, $DB; 94 95 /// Do a quick check using stripos to avoid unnecessary wor 96 if (!preg_match('/<algebra/i',$text) && !strstr($text,'@@')) { 97 return $text; 98 } 99 100 //restrict filtering to forum 130 (Maths Tools on moodle.org) 101 # $scriptname = $_SERVER['SCRIPT_NAME']; 102 # if (!strstr($scriptname,'/forum/')) { 103 # return $text; 104 # } 105 # if (strstr($scriptname,'post.php')) { 106 # $parent = forum_get_post_full($_GET['reply']); 107 # $discussion = $DB->get_record("forum_discussions",array("id"=>$parent->discussion)); 108 # } else if (strstr($scriptname,'discuss.php')) { 109 # $discussion = $DB->get_record("forum_discussions",array("id"=>$_GET['d'])); 110 # } else { 111 # return $text; 112 # } 113 # if ($discussion->forum != 130) { 114 # return $text; 115 # } 116 117 preg_match_all('/@(@@+)([^@])/',$text,$matches); 118 for ($i=0;$i<count($matches[0]);$i++) { 119 $replacement = str_replace('@','@',$matches[1][$i]).$matches[2][$i]; 120 $text = str_replace($matches[0][$i],$replacement,$text); 121 } 122 123 // <algebra> some algebraic input expression </algebra> 124 // or @@ some algebraic input expression @@ 125 126 preg_match_all('/<algebra>(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches); 127 for ($i=0; $i<count($matches[0]); $i++) { 128 $algebra = $matches[1][$i] . $matches[2][$i]; 129 130 // Look for some common false positives, and skip processing them. 131 if ($algebra == 'PLUGINFILE' || $algebra == 'DRAFTFILE') { 132 // Raw pluginfile URL. 133 continue; 134 } 135 if (preg_match('/^ -\d+(,\d+)? \+\d+(,\d+)? $/', $algebra)) { 136 // Part of a unified diff. 137 continue; 138 } 139 140 $algebra = str_replace('<nolink>','',$algebra); 141 $algebra = str_replace('</nolink>','',$algebra); 142 $algebra = str_replace('<span class="nolink">','',$algebra); 143 $algebra = str_replace('</span>','',$algebra); 144 $align = "middle"; 145 if (preg_match('/^align=bottom /',$algebra)) { 146 $align = "text-bottom"; 147 $algebra = preg_replace('/^align=bottom /','',$algebra); 148 } else if (preg_match('/^align=top /',$algebra)) { 149 $align = "text-top"; 150 $algebra = preg_replace('/^align=top /','',$algebra); 151 } 152 $md5 = md5($algebra); 153 $filename = $md5 . ".gif"; 154 if (! $texcache = $DB->get_record("cache_filters",array("filter"=>"algebra", "md5key"=>$md5))) { 155 $algebra = str_replace('<','<',$algebra); 156 $algebra = str_replace('>','>',$algebra); 157 $algebra = str_replace('<>','#',$algebra); 158 $algebra = str_replace('<=','%',$algebra); 159 $algebra = str_replace('>=','!',$algebra); 160 $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra); 161 $algebra = str_replace('delta','zdelta',$algebra); 162 $algebra = str_replace('beta','bita',$algebra); 163 $algebra = str_replace('theta','thita',$algebra); 164 $algebra = str_replace('zeta','zita',$algebra); 165 $algebra = str_replace('eta','xeta',$algebra); 166 $algebra = str_replace('epsilon','zepslon',$algebra); 167 $algebra = str_replace('upsilon','zupslon',$algebra); 168 $algebra = preg_replace('!\r\n?!',' ',$algebra); 169 $algebra = escapeshellarg($algebra); 170 if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows")) { 171 $cmd = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra"; 172 } else { 173 $cmd = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra"; 174 } 175 $texexp = `$cmd`; 176 if (preg_match('/parsehilight/',$texexp)) { 177 $text = str_replace( $matches[0][$i],"<b>Syntax error:</b> " . $texexp,$text); 178 } else if ($texexp) { 179 $texexp = str_replace('zeroplace','',$texexp); 180 $texexp = str_replace('#','\not= ',$texexp); 181 $texexp = str_replace('%','\leq ',$texexp); 182 $texexp = str_replace('!','\geq ',$texexp); 183 $texexp = str_replace('\left{','{',$texexp); 184 $texexp = str_replace('\right}','}',$texexp); 185 $texexp = str_replace('\fun',' ',$texexp); 186 $texexp = str_replace('infty','\infty',$texexp); 187 $texexp = str_replace('alpha','\alpha',$texexp); 188 $texexp = str_replace('gamma','\gamma',$texexp); 189 $texexp = str_replace('iota','\iota',$texexp); 190 $texexp = str_replace('kappa','\kappa',$texexp); 191 $texexp = str_replace('lambda','\lambda',$texexp); 192 $texexp = str_replace('mu','\mu',$texexp); 193 $texexp = str_replace('nu','\nu',$texexp); 194 $texexp = str_replace('xi','\xi',$texexp); 195 $texexp = str_replace('rho','\rho',$texexp); 196 $texexp = str_replace('sigma','\sigma',$texexp); 197 $texexp = str_replace('tau','\tau',$texexp); 198 $texexp = str_replace('phi','\phi',$texexp); 199 $texexp = str_replace('chi','\chi',$texexp); 200 $texexp = str_replace('psi','\psi',$texexp); 201 $texexp = str_replace('omega','\omega',$texexp); 202 $texexp = str_replace('zdelta','\delta',$texexp); 203 $texexp = str_replace('bita','\beta',$texexp); 204 $texexp = str_replace('thita','\theta',$texexp); 205 $texexp = str_replace('zita','\zeta',$texexp); 206 $texexp = str_replace('xeta','\eta',$texexp); 207 $texexp = str_replace('zepslon','\epsilon',$texexp); 208 $texexp = str_replace('zupslon','\upsilon',$texexp); 209 $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp); 210 $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp); 211 $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp); 212 $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp); 213 $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp); 214 $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp); 215 $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp); 216 $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp); 217 $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp); 218 $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp); 219 $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp); 220 $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp); 221 $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp); 222 //$texexp = preg_replace('/\\\frac{(.+?)}{\\\left\((.+?)\\\right\)}/s','\frac{'."\$1}{\$2}",$texexp); 223 $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp); 224 $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp); 225 $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp); 226 $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp); 227 $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp); 228 $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp); 229 $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp); 230 // Remove a forbidden keyword. 231 $texexp = str_replace('\mbox', '', $texexp); 232 $texcache = new stdClass(); 233 $texcache->filter = 'algebra'; 234 $texcache->version = 1; 235 $texcache->md5key = $md5; 236 $texcache->rawtext = $texexp; 237 $texcache->timemodified = time(); 238 $DB->insert_record("cache_filters", $texcache, false); 239 $text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texexp, '', '', $align), $text); 240 } else { 241 $text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> " . $matches[0][$i], $text); 242 } 243 } else { 244 $text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texcache->rawtext), $text); 245 } 246 } 247 return $text; 248 } 249 } 250 251
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