filter/algebra/algebradebug.php

   1 <?php
   2       // This function fetches math. images from the data directory
   3       // If not, it obtains the corresponding TeX expression from the cache_tex db table
   4       // and uses mimeTeX to create the image file
   5
   6     require_once("../../config.php");
   7
   8     if (!filter_is_enabled('algebra')) {
   9         print_error('filternotenabled');
  10     }
  11
  12     require_once($CFG->libdir.'/filelib.php');
  13     require_once($CFG->dirroot.'/filter/tex/lib.php');
  14
  15     $action = optional_param('action', '', PARAM_ALPHANUM);
  16     $algebra = optional_param('algebra', '', PARAM_RAW);
  17
  18     require_login();
  19     require_capability('moodle/site:config', context_system::instance());
  20     if ($action || $algebra) {
  21         require_sesskey();
  22     }
  23
  24     if ($algebra && $action) {
  25       $md5 = md5($algebra);
  26       if ($action == 'ShowDB' || $action == 'DeleteDB') {
  27         $texcache = $DB->get_record("cache_filters", array("filter"=>"algebra", "md5key"=>$md5));
  28       }
  29       if ($action == 'ShowDB') {
  30         if ($texcache) {
  31           $output = "DB cache_filters entry for $algebra\n";
  32           $output .= "id = $texcache->id\n";
  33           $output .= "filter = $texcache->filter\n";
  34           $output .= "version = $texcache->version\n";
  35           $output .= "md5key = $texcache->md5key\n";
  36           $output .= "rawtext = $texcache->rawtext\n";
  37           $output .= "timemodified = $texcache->timemodified\n";
  38         } else {
  39           $output = "DB cache_filters entry for $algebra not found\n";
  40         }
  41       }
  42       if ($action == 'DeleteDB') {
  43         if ($texcache) {
  44           $output = "Deleting DB cache_filters entry for $algebra\n";
  45           $result =  $DB->delete_records("cache_filters", array("id"=>$texcache->id));
  46           if ($result) {
  47             $result = 1;
  48           } else {
  49             $result = 0;
  50           }
  51           $output .= "Number of records deleted = $result\n";
  52         } else {
  53           $output = "Could not delete DB cache_filters entry for $algebra\nbecause it could not be found.\n";
  54         }
  55       }
  56       if ($action == 'TeXStage1') {
  57         $output = algebra2tex($algebra);
  58       }
  59       if ($action == 'TexStage2') {
  60         $output = algebra2tex($algebra);
  61         $output = refineTeX($output);
  62       }
  63       if ($action == 'ShowImage'|| $action == 'SlashArguments') {
  64         $output = algebra2tex($algebra);
  65         $output = refineTeX($output);
  66         if ($action == 'ShowImage') {
  67           tex2image($output, $md5);
  68         } else {
  69           slasharguments($output, $md5);
  70         }
  71       } else {
  72         outputText($output);
  73       }
  74       exit;
  75     }
  76
  77 function algebra2tex($algebra) {
  78   global $CFG;
  79   $algebra = str_replace('&lt;','<',$algebra);
  80   $algebra = str_replace('&gt;','>',$algebra);
  81   $algebra = str_replace('<>','#',$algebra);
  82   $algebra = str_replace('<=','%',$algebra);
  83   $algebra = str_replace('>=','!',$algebra);
  84   $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
  85   $algebra = str_replace('delta','zdelta',$algebra);
  86   $algebra = str_replace('beta','bita',$algebra);
  87   $algebra = str_replace('theta','thita',$algebra);
  88   $algebra = str_replace('zeta','zita',$algebra);
  89   $algebra = str_replace('eta','xeta',$algebra);
  90   $algebra = str_replace('epsilon','zepslon',$algebra);
  91   $algebra = str_replace('upsilon','zupslon',$algebra);
  92   $algebra = preg_replace('!\r\n?!',' ',$algebra);
  93   $algebra = escapeshellarg($algebra);
  94
  95   if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
  96     $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl x/2";
  97     $test = `$cmd`;
  98     if ($test != '\frac{x}{2}') {
  99       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 100       $ecmd = $cmd . " 2>&1";
 101       echo `$ecmd` . "<br/>\n";
 102       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 103       $commandpath = "$CFG->dirroot\\filter\\algebra\\algebra2tex.pl";
 104       if (file_exists($commandpath)) {
 105         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 106       }
 107       die;
 108     }
 109     $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
 110   } else {
 111     $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl x/2";
 112     $test = `$cmd`;
 113     if ($test != '\frac{x}{2}') {
 114       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 115       $ecmd = $cmd . " 2>&1";
 116       echo `$ecmd` . "<br/>\n";
 117       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 118       $commandpath = "$CFG->dirroot/filter/algebra/algebra2tex.pl";
 119       if (file_exists($commandpath)) {
 120         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 121       }
 122       die;
 123     }
 124     $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
 125   }
 126   $texexp = `$cmd`;
 127   return $texexp;
 128 }
 129
 130 function refineTeX($texexp) {
 131   $texexp = str_replace('zeroplace','',$texexp);
 132   $texexp = str_replace('#','\not= ',$texexp);
 133   $texexp = str_replace('%','\leq ',$texexp);
 134   $texexp = str_replace('!','\geq ',$texexp);
 135   $texexp = str_replace('\left{','{',$texexp);
 136   $texexp = str_replace('\right}','}',$texexp);
 137   $texexp = str_replace('\fun',' ',$texexp);
 138   $texexp = str_replace('infty','\infty',$texexp);
 139   $texexp = str_replace('alpha','\alpha',$texexp);
 140   $texexp = str_replace('gamma','\gamma',$texexp);
 141   $texexp = str_replace('iota','\iota',$texexp);
 142   $texexp = str_replace('kappa','\kappa',$texexp);
 143   $texexp = str_replace('lambda','\lambda',$texexp);
 144   $texexp = str_replace('mu','\mu',$texexp);
 145   $texexp = str_replace('nu','\nu',$texexp);
 146   $texexp = str_replace('xi','\xi',$texexp);
 147   $texexp = str_replace('rho','\rho',$texexp);
 148   $texexp = str_replace('sigma','\sigma',$texexp);
 149   $texexp = str_replace('tau','\tau',$texexp);
 150   $texexp = str_replace('phi','\phi',$texexp);
 151   $texexp = str_replace('chi','\chi',$texexp);
 152   $texexp = str_replace('psi','\psi',$texexp);
 153   $texexp = str_replace('omega','\omega',$texexp);
 154   $texexp = str_replace('zdelta','\delta',$texexp);
 155   $texexp = str_replace('bita','\beta',$texexp);
 156   $texexp = str_replace('thita','\theta',$texexp);
 157   $texexp = str_replace('zita','\zeta',$texexp);
 158   $texexp = str_replace('xeta','\eta',$texexp);
 159   $texexp = str_replace('zepslon','\epsilon',$texexp);
 160   $texexp = str_replace('zupslon','\upsilon',$texexp);
 161   $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
 162   $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
 163   $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
 164   $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
 165   $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
 166   $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
 167   $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
 168   $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
 169   $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
 170   $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
 171   $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
 172   $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
 173   $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
 174   $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
 175   $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
 176   $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
 177   $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
 178   $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
 179   $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
 180   $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
 181   return $texexp;
 182 }
 183
 184 function outputText($texexp) {
 185   header("Content-type: text/html; charset=utf-8");
 186   echo "<html><body><pre>\n";
 187   if ($texexp) {
 188     $texexp = str_replace('<','&lt;',$texexp);
 189     $texexp = str_replace('>','&gt;',$texexp);
 190     $texexp = str_replace('"','&quot;',$texexp);
 191     echo "$texexp\n\n";
 192   } else {
 193     echo "No text output available\n\n";
 194   }
 195   echo "</pre></body></html>\n";
 196 }
 197
 198 function tex2image($texexp, $md5, $return=false) {
 199     global $CFG;
 200
 201     if (!$texexp) {
 202         echo 'No tex expresion specified';
 203         return;
 204     }
 205
 206     $texexp = '\Large ' . $texexp;
 207     $image  = $md5 . ".gif";
 208     $filetype = 'image/gif';
 209     if (!file_exists("$CFG->dataroot/filter/algebra")) {
 210         make_upload_directory("filter/algebra");
 211     }
 212     $pathname = "$CFG->dataroot/filter/algebra/$image";
 213     if (file_exists($pathname)) {
 214         unlink($pathname);
 215     }
 216     $commandpath = filter_tex_get_executable(true);
 217     $cmd = filter_tex_get_cmd($pathname, $texexp);
 218     system($cmd, $status);
 219
 220     if ($return) {
 221         return $image;
 222     }
 223     if (file_exists($pathname)) {
 224         send_file($pathname, $image);
 225
 226     } else {
 227         $ecmd = "$cmd 2>&1";
 228         echo `$ecmd` . "<br />\n";
 229         echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 230         if ($status == 4) {
 231             echo "Status corresponds to illegal instruction<br />\n";
 232         } else if ($status == 11) {
 233             echo "Status corresponds to bus error<br />\n";
 234         } else if ($status == 22) {
 235             echo "Status corresponds to abnormal termination<br />\n";
 236         }
 237         if (file_exists($commandpath)) {
 238             echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 239             echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 240             if (function_exists("md5_file")) {
 241                 echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 242             } else {
 243                 $handle = fopen($commandpath,"rb");
 244                 $contents = fread($handle,16384);
 245                 fclose($handle);
 246                 echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 247             }
 248         } else {
 249             echo "mimetex executable $commandpath not found!<br />";
 250         }
 251         echo "Image not found!";
 252     }
 253 }
 254
 255 function slasharguments($texexp, $md5) {
 256   global $CFG;
 257   $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 258   $image = tex2image($texexp,$md5,true);
 259   echo "<p>If the following image displays correctly, set your ";
 260   echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 261   echo "setting for slasharguments to file.php/1/pic.jpg: ";
 262   echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 263   echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 264   echo "It should display correctly as ";
 265   echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 266   echo "<p>If neither equation image displays correctly, please seek ";
 267   echo "further help at moodle.org at the ";
 268   echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 269   echo "Mathematics Tools Forum</a></p>";
 270 }
 271
 272 ?>
 273
 274 <html>
 275 <head><title>Algebra Filter Debugger</title></head>
 276 <body>
 277     <p>Please enter an algebraic expression <b>without</b> any surrounding @@ into
 278        the text box below. (Click <a href="#help">here for help.</a>)
 279           <form action="algebradebug.php" method="get"
 280            target="inlineframe">
 281             <center>
 282              <label for="algebra" class="accesshide"><?php print_string('algebraicexpression', 'filter_algebra'); ?></label>
 283              <input type="text" id="algebra" name="algebra" size="50"
 284                     value="sin(z)/(x^2+y^2)" />
 285             </center>
 286            <ol>
 287            <li>First click on this button <button type="submit" name="action" value="ShowDB">Show DB Entry</button>
 288                to see the cache_filters database entry for this expression.</li>
 289            <li>If the database entry looks corrupt, click on this button to delete it:
 290                <button type="submit" name="action" value="DeleteDB">Delete DB Entry</button></li>
 291            <li>Now click on this button <button type="submit" name="action" value="TeXStage1">First Stage Tex Translation</button>.
 292                A preliminary translation into TeX will appear in the box below.</li>
 293            <li>Next click on this button <button type="submit" name="action" value="TexStage2">Second Stage Tex Translation</button>.
 294                A more refined translation into TeX will appear in the box below.</li>
 295            <li>Then click on this button <button type="submit" name="action" value="ShowImage">Show Image</button>
 296                to show a graphic image of the algebraic expression.</li>
 297            <li>Finally check your slash arguments setting
 298                <button type="submit" name="action" value="SlashArguments">Check Slash Arguments</button></li>
 299            </ol>
 300            <input type="hidden" name="sesskey" value="<?php echo sesskey(); ?>" />
 301           </form> <br /> <br />
 302        <center>
 303           <iframe name="inlineframe" align="middle" width="80%" height="200">
 304           &lt;p&gt;Something is wrong...&lt;/p&gt;
 305           </iframe>
 306        </center> <br />
 307 <hr />
 308 <a name="help">
 309 <h2>Debugging Help</h2>
 310 </a>
 311 <p>First here is a brief overview on how the algebra filter works. It
 312 takes an algebra expression and first translates it into TeX.  It first
 313 looks for the TeX translation in the Moodle database in the table cache_filters
 314 in the field rawtext. If not found, it passes the algebraic expression to the
 315 Perl script algebra2tex.pl, which also uses the Perl library AlgParser.pm.
 316 It then saves the TeX translation in the database for subsequent uses and
 317 passes the TeX to the mimetex executable to be converted to a gif image.
 318 Here are a few common things that can go wrong and some suggestions on how
 319 you might try to fix them.</p>
 320 <ol>
 321 <li>Something had gone wrong on a previous occasion when the filter tried to
 322 translate this expression. Then the database entry for that expression contains
 323 a bad TeX translation in the rawtext field (usually blank). You can fix this
 324 by clicking on &quot;Delete DB Entry&quot;</li>
 325 <li>The First Stage TeX Translation gives a &quot;No text output available&quot;
 326 message. If your server is running Windows, this may be due to the fact that
 327 you haven't installed Perl or didn't install it correctly. If your server is
 328 running some version of Unix (e.g. Linux), then this may be due to your Perl
 329 binary being installed in a nonstandard location. To fix this edit the first
 330 line of the algebra2tex.pl script. Another possible problem which may affect
 331 both Unix and Windows servers is that the web server doesn't have execute permission
 332 on the algebra2tex.pl script. In that case change permissions accordingly</li>
 333 <li>The Second Stage TeX Translation produces malformed TeX. This indicates
 334 a bug in the algebra filter. Post the original algebraic expression and the
 335 bad TeX translation in the <a href="http://moodle.org/mod/forum/view.php?id=752">
 336 Mathematics Tools</a> forum in the Using Moodle course on moodle.org.</li>
 337 <li>The TeX to gif image conversion process does not work. If your server is
 338 running Unix, a likely cause is that the mimetex binary you are using is
 339 incompatible with your operating system. You can try compiling it from the
 340 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 341 http://www.forkosh.com/mimetex.zip</a>. Lastly check the execute permissions
 342 on your mimetex binary, as outlined in item 2 above.</li>
 343 </ol>
 344 </body>
 345 </html>