filter/algebra/algebradebug.php

   1 <?PHP // $Id$
   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     $nomoodlecookie = true;     // Because it interferes with caching
   7
   8     require_once("../../config.php");
   9
  10     if (empty($CFG->textfilters)) {
  11         error ('Filter not enabled!');
  12     } else {
  13         $filters = explode(',', $CFG->textfilters);
  14         if (array_search('filter/algebra', $filters) === FALSE) {
  15             error ('Filter not enabled!');
  16         }
  17     }
  18
  19     require_once($CFG->libdir.'/filelib.php');
  20     require_once($CFG->dirroot.'/filter/tex/lib.php');
  21
  22     $query = urldecode($_SERVER['QUERY_STRING']);
  23     error_reporting(E_ALL);
  24
  25     if ($query) {
  26       $output = $query;
  27       $splitpos = strpos($query,'&')-8;
  28       $algebra = substr($query,8,$splitpos);
  29       $md5 = md5($algebra);
  30       if (strpos($query,'ShowDB') || strpos($query,'DeleteDB')) {
  31         $texcache = get_record("cache_filters","filter","algebra", "md5key", $md5);
  32       }
  33       if (strpos($query,'ShowDB')) {
  34         if ($texcache) {
  35           $output = "DB cache_filters entry for $algebra\n";
  36           $output .= "id = $texcache->id\n";
  37           $output .= "filter = $texcache->filter\n";
  38           $output .= "version = $texcache->version\n";
  39           $output .= "md5key = $texcache->md5key\n";
  40           $output .= "rawtext = $texcache->rawtext\n";
  41           $output .= "timemodified = $texcache->timemodified\n";
  42         } else {
  43           $output = "DB cache_filters entry for $algebra not found\n";
  44         }
  45       }
  46       if (strpos($query,'DeleteDB')) {
  47         if ($texcache) {
  48           $output = "Deleting DB cache_filters entry for $algebra\n";
  49           $result =  delete_records("cache_filters","id",$texcache->id);
  50           if ($result) {
  51             $result = 1;
  52           } else {
  53             $result = 0;
  54           }
  55           $output .= "Number of records deleted = $result\n";
  56         } else {
  57           $output = "Could not delete DB cache_filters entry for $algebra\nbecause it could not be found.\n";
  58         }
  59       }
  60       if (strpos($query,'TeXStage1')) {
  61         $output = algebra2tex($algebra);
  62       }
  63       if (strpos($query,'TeXStage2')) {
  64         $output = algebra2tex($algebra);
  65         $output = refineTeX($output);
  66       }
  67       if (strpos($query,'ShowImage')||strpos($query,'SlashArguments')) {
  68         $output = algebra2tex($algebra);
  69         $output = refineTeX($output);
  70         if (strpos($query,'ShowImage')) {
  71           tex2image($output, $md5);
  72         } else {
  73           slasharguments($output, $md5);
  74         }
  75       } else {
  76         outputText($output);
  77       }
  78       exit;
  79     }
  80
  81 function algebra2tex($algebra) {
  82   global $CFG;
  83   $algebra = str_replace('&lt;','<',$algebra);
  84   $algebra = str_replace('&gt;','>',$algebra);
  85   $algebra = str_replace('<>','#',$algebra);
  86   $algebra = str_replace('<=','%',$algebra);
  87   $algebra = str_replace('>=','!',$algebra);
  88   $algebra = preg_replace('/([=><%!#] *)-/',"\$1 zeroplace -",$algebra);
  89   $algebra = str_replace('delta','zdelta',$algebra);
  90   $algebra = str_replace('beta','bita',$algebra);
  91   $algebra = str_replace('theta','thita',$algebra);
  92   $algebra = str_replace('zeta','zita',$algebra);
  93   $algebra = str_replace('eta','xeta',$algebra);
  94   $algebra = str_replace('epsilon','zepslon',$algebra);
  95   $algebra = str_replace('upsilon','zupslon',$algebra);
  96   $algebra = preg_replace('!\r\n?!',' ',$algebra);
  97   $algebra = escapeshellarg($algebra);
  98
  99   if ( (PHP_OS == "WINNT") || (PHP_OS == "WIN32") || (PHP_OS == "Windows") ) {
 100     $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl x/2";
 101     $test = `$cmd`;
 102     if ($test != '\frac{x}{2}') {
 103       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 104       $ecmd = $cmd . " 2>&1";
 105       echo `$ecmd` . "<br/>\n";
 106       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 107       $commandpath = "$CFG->dirroot\\filter\\algebra\\algebra2tex.pl";
 108       if (file_exists($commandpath)) {
 109         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 110       }
 111       die;
 112     }
 113     $cmd  = "cd $CFG->dirroot\\filter\\algebra & algebra2tex.pl $algebra";
 114   } else {
 115     $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl x/2";
 116     $test = `$cmd`;
 117     if ($test != '\frac{x}{2}') {
 118       echo "There is a problem with either Perl or the script algebra2tex.pl<br/>";
 119       $ecmd = $cmd . " 2>&1";
 120       echo `$ecmd` . "<br/>\n";
 121       echo "The shell command<br/>$cmd<br/>returned status = $status<br/>\n";
 122       $commandpath = "$CFG->dirroot/filter/algebra/algebra2tex.pl";
 123       if (file_exists($commandpath)) {
 124         echo "The file permissions of algebra2tex.pl are: " . decoct(fileperms($commandpath)) . "<br/>";
 125       }
 126       die;
 127     }
 128     $cmd  = "cd $CFG->dirroot/filter/algebra; ./algebra2tex.pl $algebra";
 129   }
 130   $texexp = `$cmd`;
 131   return $texexp;
 132 }
 133
 134 function refineTeX($texexp) {
 135   $texexp = str_replace('zeroplace','',$texexp);
 136   $texexp = str_replace('#','\not= ',$texexp);
 137   $texexp = str_replace('%','\leq ',$texexp);
 138   $texexp = str_replace('!','\geq ',$texexp);
 139   $texexp = str_replace('\left{','{',$texexp);
 140   $texexp = str_replace('\right}','}',$texexp);
 141   $texexp = str_replace('\fun',' ',$texexp);
 142   $texexp = str_replace('infty','\infty',$texexp);
 143   $texexp = str_replace('alpha','\alpha',$texexp);
 144   $texexp = str_replace('gamma','\gamma',$texexp);
 145   $texexp = str_replace('iota','\iota',$texexp);
 146   $texexp = str_replace('kappa','\kappa',$texexp);
 147   $texexp = str_replace('lambda','\lambda',$texexp);
 148   $texexp = str_replace('mu','\mu',$texexp);
 149   $texexp = str_replace('nu','\nu',$texexp);
 150   $texexp = str_replace('xi','\xi',$texexp);
 151   $texexp = str_replace('rho','\rho',$texexp);
 152   $texexp = str_replace('sigma','\sigma',$texexp);
 153   $texexp = str_replace('tau','\tau',$texexp);
 154   $texexp = str_replace('phi','\phi',$texexp);
 155   $texexp = str_replace('chi','\chi',$texexp);
 156   $texexp = str_replace('psi','\psi',$texexp);
 157   $texexp = str_replace('omega','\omega',$texexp);
 158   $texexp = str_replace('zdelta','\delta',$texexp);
 159   $texexp = str_replace('bita','\beta',$texexp);
 160   $texexp = str_replace('thita','\theta',$texexp);
 161   $texexp = str_replace('zita','\zeta',$texexp);
 162   $texexp = str_replace('xeta','\eta',$texexp);
 163   $texexp = str_replace('zepslon','\epsilon',$texexp);
 164   $texexp = str_replace('zupslon','\upsilon',$texexp);
 165   $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$texexp);
 166   $texexp = str_replace('\mbox{acos}','\mbox{cos}^{-1}',$texexp);
 167   $texexp = str_replace('\mbox{asin}','\mbox{sin}^{-1}',$texexp);
 168   $texexp = str_replace('\mbox{atan}','\mbox{tan}^{-1}',$texexp);
 169   $texexp = str_replace('\mbox{asec}','\mbox{sec}^{-1}',$texexp);
 170   $texexp = str_replace('\mbox{acsc}','\mbox{csc}^{-1}',$texexp);
 171   $texexp = str_replace('\mbox{acot}','\mbox{cot}^{-1}',$texexp);
 172   $texexp = str_replace('\mbox{acosh}','\mbox{cosh}^{-1}',$texexp);
 173   $texexp = str_replace('\mbox{asinh}','\mbox{sinh}^{-1}',$texexp);
 174   $texexp = str_replace('\mbox{atanh}','\mbox{tanh}^{-1}',$texexp);
 175   $texexp = str_replace('\mbox{asech}','\mbox{sech}^{-1}',$texexp);
 176   $texexp = str_replace('\mbox{acsch}','\mbox{csch}^{-1}',$texexp);
 177   $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
 178   $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
 179   $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$1|",$texexp);
 180   $texexp = preg_replace('/\\\log\\\left\((.+?),(.+?)\\\right\)/s','\log_{'. "\$2}\\left(\$1\\right)",$texexp);
 181   $texexp = preg_replace('/(\\\cos|\\\sin|\\\tan|\\\sec|\\\csc|\\\cot)([h]*)\\\left\((.+?),(.+?)\\\right\)/s',"\$1\$2^{". "\$4}\\left(\$3\\right)",$texexp);
 182   $texexp = preg_replace('/\\\int\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\int_'. "{\$2}^{\$3}\$1 ",$texexp);
 183   $texexp = preg_replace('/\\\int\\\left\((.+?d[a-z])\\\right\)/s','\int '. "\$1 ",$texexp);
 184   $texexp = preg_replace('/\\\lim\\\left\((.+?),(.+?),(.+?)\\\right\)/s','\lim_'. "{\$2\\to \$3}\$1 ",$texexp);
 185   return $texexp;
 186 }
 187
 188 function outputText($texexp) {
 189   header("Content-type: text/html");
 190   echo "<html><body><pre>\n";
 191   if ($texexp) {
 192     $texexp = str_replace('<','&lt;',$texexp);
 193     $texexp = str_replace('>','&gt;',$texexp);
 194     $texexp = str_replace('"','&quot;',$texexp);
 195     echo "$texexp\n\n";
 196   } else {
 197     echo "No text output available\n\n";
 198   }
 199   echo "</pre></body></html>\n";
 200 }
 201
 202 function tex2image($texexp, $md5, $return=false) {
 203     global $CFG;
 204
 205     if (!$texexp) {
 206         echo 'No tex expresion specified';
 207         return;
 208     }
 209
 210     $texexp = '\Large ' . $texexp;
 211     $image  = $md5 . ".gif";
 212     $filetype = 'image/gif';
 213     if (!file_exists("$CFG->dataroot/filter/algebra")) {
 214         make_upload_directory("filter/algebra");
 215     }
 216     $pathname = "$CFG->dataroot/filter/algebra/$image";
 217     if (file_exists($pathname)) {
 218         unlink($pathname);
 219     }
 220     $commandpath = tex_filter_get_executable(true);
 221     $cmd = tex_filter_get_cmd($pathname, $texexp);
 222     system($cmd, $status);
 223
 224     if ($return) {
 225         return $image;
 226     }
 227     if (file_exists($pathname)) {
 228         send_file($pathname, $image);
 229
 230     } else {
 231         $ecmd = "$cmd 2>&1";
 232         echo `$ecmd` . "<br />\n";
 233         echo "The shell command<br />$cmd<br />returned status = $status<br />\n";
 234         if ($status == 4) {
 235             echo "Status corresponds to illegal instruction<br />\n";
 236         } else if ($status == 11) {
 237             echo "Status corresponds to bus error<br />\n";
 238         } else if ($status == 22) {
 239             echo "Status corresponds to abnormal termination<br />\n";
 240         }
 241         if (file_exists($commandpath)) {
 242             echo "File size of mimetex executable  $commandpath is " . filesize($commandpath) . "<br />";
 243             echo "The file permissions are: " . decoct(fileperms($commandpath)) . "<br />";
 244             if (function_exists("md5_file")) {
 245                 echo "The md5 checksum of the file is " . md5_file($commandpath) . "<br />";
 246             } else {
 247                 $handle = fopen($commandpath,"rb");
 248                 $contents = fread($handle,16384);
 249                 fclose($handle);
 250                 echo "The md5 checksum of the first 16384 bytes is " . md5($contents) . "<br />";
 251             }
 252         } else {
 253             echo "mimetex executable $commandpath not found!<br />";
 254         }
 255         echo "Image not found!";
 256     }
 257 }
 258
 259 function slasharguments($texexp, $md5) {
 260   global $CFG;
 261   $admin = $CFG->wwwroot.'/'.$CFG->admin.'/settings.php?section=http';
 262   $image = tex2image($texexp,$md5,true);
 263   echo "<p>If the following image displays correctly, set your ";
 264   echo "<a href=\"$admin\" target=\"_blank\">Administration->Server->HTTP</a> ";
 265   echo "setting for slasharguments to file.php/1/pic.jpg: ";
 266   echo "<img src=\"pix.php/$image\" align=\"absmiddle\"></p>\n";
 267   echo "<p>Otherwise set it to file.php?file=/1/pic.jpg ";
 268   echo "It should display correctly as ";
 269   echo "<img src=\"pix.php?file=$image\" align=\"absmiddle\"></p>\n";
 270   echo "<p>If neither equation image displays correctly, please seek ";
 271   echo "further help at moodle.org at the ";
 272   echo "<a href=\"http://moodle.org/mod/forum/view.php?id=752&loginguest=true\" target=\"_blank\">";
 273   echo "Mathematics Tools Forum</a></p>";
 274 }
 275
 276 ?>
 277
 278 <html>
 279 <head><title>Algebra Filter Debugger</title></head>
 280 <body>
 281     <p>Please enter an algebraic expression <b>without</b> any surrounding @@ into
 282        the text box below. (Click <a href="#help">here for help.</a>)
 283           <form action="algebradebug.php" method="get"
 284            target="inlineframe">
 285             <center>
 286              <input type="text" name="algebra" size="50"
 287                     value="sin(z)/(x^2+y^2)" />
 288             </center>
 289            <ol>
 290            <li>First click on this button <input type="submit" name="ShowDB" value="Show DB Entry" />
 291                to see the cache_filters database entry for this expression.</li>
 292            <li>If the database entry looks corrupt, click on this button to delete it:
 293                <input type="submit" name="DeleteDB" value="Delete DB Entry" /></li>
 294            <li>Now click on this button <input type="submit" name="TeXStage1" value="First Stage Tex Translation" />.
 295                A preliminary translation into TeX will appear in the box below.</li>
 296            <li>Next click on this button <input type="submit" name="TeXStage2" value="Second Stage Tex Translation" />.
 297                A more refined translation into TeX will appear in the box below.</li>
 298            <li>Then click on this button <input type="submit" name="ShowImage" value="Show Image" />
 299                to show a graphic image of the algebraic expression.</li>
 300            <li>Finally check your slash arguments setting
 301                <input type="submit" name="SlashArguments" value="Check Slash Arguments" /></li>
 302            </ol>
 303           </form> <br /> <br />
 304        <center>
 305           <iframe name="inlineframe" align="middle" width="80%" height="200">
 306           &lt;p&gt;Something is wrong...&lt;/p&gt;
 307           </iframe>
 308        </center> <br />
 309 <hr />
 310 <a name="help">
 311 <h2>Debugging Help</h2>
 312 </a>
 313 <p>First here is a brief overview on how the algebra filter works. It
 314 takes an algebra expression and first translates it into TeX.  It first
 315 looks for the TeX translation in the Moodle database in the table cache_filters
 316 in the field rawtext. If not found, it passes the algebraic expression to the
 317 Perl script algebra2tex.pl, which also uses the Perl library AlgParser.pm.
 318 It then saves the TeX translation in the database for subsequent uses and
 319 passes the TeX to the mimetex executable to be converted to a gif image.
 320 Here are a few common things that can go wrong and some suggestions on how
 321 you might try to fix them.</p>
 322 <ol>
 323 <li>Something had gone wrong on a previous occasion when the filter tried to
 324 translate this expression. Then the database entry for that expression contains
 325 a bad TeX translation in the rawtext field (usually blank). You can fix this
 326 by clicking on &quot;Delete DB Entry&quot;</li>
 327 <li>The First Stage TeX Translation gives a &quot;No text output available&quot;
 328 message. If your server is running Windows, this may be due to the fact that
 329 you haven't installed Perl or didn't install it correctly. If your server is
 330 running some version of Unix (e.g. Linux), then this may be due to your Perl
 331 binary being installed in a nonstandard location. To fix this edit the first
 332 line of the algebra2tex.pl script. Another possible problem which may affect
 333 both Unix and Windows servers is that the web server doesn't have execute permission
 334 on the algebra2tex.pl script. In that case change permissions accordingly</li>
 335 <li>The Second Stage TeX Translation produces malformed TeX. This indicates
 336 a bug in the algebra filter. Post the original algebraic expression and the
 337 bad TeX translation in the <a href="http://moodle.org/mod/forum/view.php?id=752">
 338 Mathematics Tools</a> forum in the Using Moodle course on moodle.org.</li>
 339 <li>The TeX to gif image conversion process does not work. If your server is
 340 running Unix, a likely cause is that the mimetex binary you are using is
 341 incompatible with your operating system. You can try compiling it from the
 342 C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
 343 http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
 344 binary at <a href="http://moodle.org/download/mimetex/">
 345 http://moodle.org/download/mimetex/</a>. You may then also need to
 346 edit your moodle/filter/algebra/pix.php file to add
 347 <br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
 348 in the switch (PHP_OS) statement. Windows users may have a problem properly
 349 unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
 350 433152 bytes in size. If not, download fresh copy from
 351 <a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
 352 http://moodle.org/download/mimetex/windows/mimetex.exe</a>. Lastly check
 353 the execute permissions on your mimetex binary, as outlined in item 2 above.</li>
 354 </ol>
 355 </body>
 356 </html>