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<?PHP
/////////////////////////////////////////////////////////////////////////////
// //
// NOTICE OF COPYRIGHT //
// //
// Moodle - Filter for converting simple calculator-type algebraic //
// expressions to cached gif images //
// //
// Copyright (C) 2004 Zbigniew Fiedorowicz fiedorow@math.ohio-state.edu //
// Originally based on code provided by Bruno Vernier bruno@vsbeducation.ca//
// This program 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 2 of the License, or //
// (at your option) any later version. //
// //
// This program 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: //
// //
// http://www.gnu.org/copyleft/gpl.html //
// //
/////////////////////////////////////////////////////////////////////////////
//-------------------------------------------------------------------------
// NOTE: This Moodle text filter converts algebraic expressions delimited
// by either @@...@@ or by <algebra...>...</algebra> tags
// first converts it to TeX using WeBWorK algebra parser Perl library
// AlgParser.pm, part of the WeBWorK distribution obtained from
// http://webhost.math.rochester.edu/downloadwebwork/
// then converts the TeX to gif images using
// mimetex.cgi obtained from http://www.forkosh.com/mimetex.html authored by
// John Forkosh john@forkosh.com. The mimetex.cgi ELF binary compiled for Linux i386
// as well as AlgParser.pm are included with this distribution.
// Note that there may be patent restrictions on the production of gif images
// in Canada and some parts of Western Europe and Japan until July 2004.
//-------------------------------------------------------------------------
// You will then need to edit your moodle/config.php to invoke mathml_filter.php
//-------------------------------------------------------------------------
/// Edit these lines to correspond to your installation
// File path to the directory where mathml_filter.php resides
$CFG->algebrafilterdir = "filter/algebra";
$CFG->texfilterdir = "filter/tex";
/// These lines are important - the variable must match the name
/// of the actual function below
$textfilter_function='algebra_filter';
if (function_exists($textfilter_function)) {
return;
}
function string_file_picture_algebra($imagefile, $tex= "", $height="", $width="") {
// Given the path to a picture file in a course, or a URL,
// this function includes the picture in the page.
global $CFG;
$output = "";
if ($tex) {
$tex = str_replace('&','&amp;',$tex);
$tex = str_replace('<','&lt;',$tex);
$tex = str_replace('>','&gt;',$tex);
$tex = str_replace('"','&quot;',$tex);
$tex = str_replace("\'",'&#39;',$tex);
$title = "title=\"$tex\"";
}
if ($height) {
$height = "height=\"$height\"";
}
if ($width) {
$width = "width=\"$width\"";
}
if ($imagefile) {
if (!file_exists("$CFG->dataroot/$CFG->algebrafilterdir/$imagefile") && isadmin()) {
$output .= "<a href=\"$CFG->wwwroot/$CFG->algebrafilterdir/algebradebug.php\">";
} else {
$output .= "<a target=\"popup\" title=\"TeX\" href=";
$output .= "\"$CFG->wwwroot/$CFG->texfilterdir/displaytex.php?";
$output .= urlencode($tex) . "\" onClick=\"return openpopup('/$CFG->texfilterdir/displaytex.php?";
$output .= urlencode($tex) . "', 'popup', 'menubar=0,location=0,scrollbars,";
$output .= "resizable,width=300,height=240', 0);\">";
}
$output .= "<img border=\"0\" $title $height $width src=\"";
if ($CFG->slasharguments) { // Use this method if possible for better caching
$output .= "$CFG->wwwroot/$CFG->algebrafilterdir/pix.php/$imagefile";
} else {
$output .= "$CFG->wwwroot/$CFG->algebrafilterdir/pix.php?file=$imagefile";
}
$output .= "\" />";
$output .= "</a>";
} else {
$output .= "Error: must pass URL or course";
}
return $output;
}
function algebra_filter ($courseid, $text) {
global $CFG;
/// Do a quick check using stripos to avoid unnecessary wor
if (!preg_match('/<algebra/i',$text) && !strstr($text,'@@')) {
return $text;
}
# //restrict filtering to forum 130 (Maths Tools on moodle.org)
# $scriptname = $_SERVER['SCRIPT_NAME'];
# if (!strstr($scriptname,'/forum/')) {
# return $text;
# }
# if (strstr($scriptname,'post.php')) {
# $parent = forum_get_post_full($_GET['reply']);
# $discussion = get_record("forum_discussions","id",$parent->discussion);
# } else if (strstr($scriptname,'discuss.php')) {
# $discussion = get_record("forum_discussions","id",$_GET['d'] );
# } else {
# return $text;
# }
# if ($discussion->forum != 130) {
# return $text;
# }
$text .= ' ';
preg_match_all('/@(@@+)([^@])/',$text,$matches);
for ($i=0;$i<count($matches[0]);$i++) {
$replacement = str_replace('@','&#x00040;',$matches[1][$i]).$matches[2][$i];
$text = str_replace($matches[0][$i],$replacement,$text);
}
if (isadmin()) { error_reporting (E_ALL); }; //for debugging
// <algebra> some algebraic input expression </algebra>
// or @@ some algebraic input expression @@
preg_match_all('/<algebra>(.+?)<\/algebra>|@@(.+?)@@/is', $text, $matches);
for ($i=0; $i<count($matches[0]); $i++) {
$algebra = $matches[1][$i] . $matches[2][$i];
$algebra = str_replace('<nolink>','',$algebra);
$algebra = str_replace('</nolink>','',$algebra);
$md5 = md5($algebra);
$filename = $md5 . ".gif";
if (! $texcache = get_record("cache_filters","filter","algebra", "md5key", $md5)) {
$algebra = str_replace('&lt;','<',$algebra);
$algebra = str_replace('&gt;','>',$algebra);
$algebra = str_replace('<>','#',$algebra);
$algebra = str_replace('<=','%',$algebra);
$algebra = str_replace('>=','!',$algebra);
$algebra = str_replace('delta','zdelta',$algebra);
$algebra = str_replace('beta','bita',$algebra);
$algebra = str_replace('theta','thita',$algebra);
$algebra = str_replace('zeta','zita',$algebra);
$algebra = str_replace('eta','xeta',$algebra);
$algebra = str_replace('epsilon','zepslon',$algebra);
$algebra = str_replace('upsilon','zupslon',$algebra);
$algebra = preg_replace('!\r\n?!',' ',$algebra);
if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
$algebra = "\"". str_replace('"','\"',$algebra) . "\"";
$cmd = "cd $CFG->dirroot/$CFG->algebrafilterdir & algebra2tex.pl $algebra";
} else {
$algebra = escapeshellarg($algebra);
$cmd = "cd $CFG->dirroot/$CFG->algebrafilterdir; ./algebra2tex.pl $algebra";
}
$texexp = `$cmd`;
if (preg_match('/parsehilight/',$texexp)) {
$text = str_replace( $matches[0][$i],"<b>Syntax error:</b> " . $texexp,$text);
} else if ($texexp) {
$texexp = str_replace('#','\not= ',$texexp);
$texexp = str_replace('%','\leq ',$texexp);
$texexp = str_replace('!','\geq ',$texexp);
$texexp = str_replace('\left{','{',$texexp);
$texexp = str_replace('\right}','}',$texexp);
$texexp = str_replace('\fun',' ',$texexp);
$texexp = str_replace('infty','\infty',$texexp);
$texexp = str_replace('alpha','\alpha',$texexp);
$texexp = str_replace('gamma','\gamma',$texexp);
$texexp = str_replace('iota','\iota',$texexp);
$texexp = str_replace('kappa','\kappa',$texexp);
$texexp = str_replace('lambda','\lambda',$texexp);
$texexp = str_replace('mu','\mu',$texexp);
$texexp = str_replace('nu','\nu',$texexp);
$texexp = str_replace('xi','\xi',$texexp);
$texexp = str_replace('rho','\rho',$texexp);
$texexp = str_replace('sigma','\sigma',$texexp);
$texexp = str_replace('tau','\tau',$texexp);
$texexp = str_replace('phi','\phi',$texexp);
$texexp = str_replace('chi','\chi',$texexp);
$texexp = str_replace('psi','\psi',$texexp);
$texexp = str_replace('omega','\omega',$texexp);
$texexp = str_replace('zdelta','\delta',$texexp);
$texexp = str_replace('bita','\beta',$texexp);
$texexp = str_replace('thita','\theta',$texexp);
$texexp = str_replace('zita','\zeta',$texexp);
$texexp = str_replace('xeta','\eta',$texexp);
$texexp = str_replace('zepslon','\epsilon',$texexp);
$texexp = str_replace('zupslon','\upsilon',$texexp);
$texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
$texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
$texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
$texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
$texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
$texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
$texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
$texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
$texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
$texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
$texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
$texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
$texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
//$texexp = preg_replace('/\\\frac{(.+?)}{\\\left\((.+?)\\\right\)}/s','\frac{'."\$1}{\$2}",$texexp);
$texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
$texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
$texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
$texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
$texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
$texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
$texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
$texcache->filter = 'algebra';
$texcache->version = 1;
$texcache->md5key = $md5;
$texcache->rawtext = addslashes($texexp);
$texcache->timemodified = time();
insert_record("cache_filters",$texcache);
$text = str_replace( $matches[0][$i], string_file_picture_algebra($filename, $texexp), $text);
} else {
$text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> ",$text);
}
} else {
$text = str_replace( $matches[0][$i], string_file_picture_algebra($filename, $texcache->rawtext), $text);
}
}
return $text;
}
?>
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