From 9b361d24b3457e9295eab342c2c39e6579331727 Mon Sep 17 00:00:00 2001
From: fiedorow <fiedorow>
Date: Thu, 19 Feb 2004 18:03:41 +0000
Subject: [PATCH] Added debugger for algebra filter

---
 filter/algebra/algebradebug.php | 270 ++++++++++++++++++++++++++++++++
 filter/algebra/filter.php       |   1 -
 2 files changed, 270 insertions(+), 1 deletion(-)
 create mode 100644 filter/algebra/algebradebug.php

diff --git a/filter/algebra/algebradebug.php b/filter/algebra/algebradebug.php
new file mode 100644
index 0000000000..f4301e0164
--- /dev/null
+++ b/filter/algebra/algebradebug.php
@@ -0,0 +1,270 @@
+<?PHP // $Id$
+      // This function fetches math. images from the data directory
+      // If not, it obtains the corresponding TeX expression from the cache_tex db table
+      // and uses mimeTeX to create the image file
+
+    $nomoodlecookie = true;     // Because it interferes with caching
+
+    require_once("../../config.php");
+
+
+    $CFG->texfilterdir = "filter/tex";
+    $CFG->algebrafilterdir = "filter/algebra";
+    $CFG->algebraimagedir = "filter/algebra";
+
+    error_reporting(E_ALL);
+    $query = urldecode($_SERVER['QUERY_STRING']);
+
+    if ($query) {
+      $output = $query;
+      $splitpos = strpos($query,'&')-8;
+      $algebra = substr($query,8,$splitpos);
+      $md5 = md5($algebra);
+      if (strpos($query,'ShowDB') || strpos($query,'DeleteDB')) {
+	$texcache = get_record("cache_filters","filter","algebra", "md5key", $md5);
+      }
+      if (strpos($query,'ShowDB')) {
+        if ($texcache) {
+	  $output = "DB cache_filters entry for $algebra\n";
+          $output .= "id = $texcache->id\n";
+          $output .= "filter = $texcache->filter\n";
+          $output .= "version = $texcache->version\n";
+          $output .= "md5key = $texcache->md5key\n";
+          $output .= "rawtext = $texcache->rawtext\n";
+          $output .= "timemodified = $texcache->timemodified\n";
+        } else {
+          $output = "DB cache_filters entry for $algebra not found\n";
+        }
+      }
+      if (strpos($query,'DeleteDB')) {
+        if ($texcache) {
+          $output = "Deleting DB cache_filters entry for $algebra\n";
+          $result =  delete_records("cache_filters","id",$texcache->id);
+          if ($result) {
+	    $result = 1;
+          } else {
+            $result = 0;
+          }
+          $output .= "Number of records deleted = $result\n";
+        } else {
+          $output = "Could not delete DB cache_filters entry for $algebra\nbecause it could not be found.\n";
+        }
+      }
+      if (strpos($query,'TeXStage1')) {
+	$output = algebra2tex($algebra);
+      }
+      if (strpos($query,'TeXStage2')) {
+	$output = algebra2tex($algebra);
+        $output = refineTeX($output);
+      }
+      if (strpos($query,'ShowImage')) {
+	$output = algebra2tex($algebra);
+        $output = refineTeX($output);
+        tex2image($output);
+      } else {   
+        outputText($output);
+      }
+      exit;
+    }
+
+function algebra2tex($algebra) {
+  Global $CFG;
+  $algebra = str_replace('&lt;','<',$algebra);
+  $algebra = str_replace('&gt;','>',$algebra);
+  $algebra = str_replace('<>','#',$algebra);
+  $algebra = str_replace('<=','%',$algebra);
+  $algebra = str_replace('>=','!',$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`;
+  return $texexp;
+}
+
+function refineTeX($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);
+  $texexp = str_replace('\mbox{logten}','\mbox{log}_{10}',$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);
+  $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$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);
+  return $texexp;
+}
+
+function outputText($texexp) {
+  header("Content-type: text/html");
+  echo "<html><body><pre>\n";
+  if ($texexp) {
+    $texexp = str_replace('<','&lt;',$texexp);
+    $texexp = str_replace('>','&gt;',$texexp);
+    $texexp = str_replace('"','&quot;',$texexp);
+    echo "$texexp\n\n";
+  } else {
+    echo "No text output available\n\n";
+  }
+  echo "</pre></body></html>\n";
+}
+
+function tex2image($texexp) {
+  global $CFG;
+  if ($texexp) {
+       $texexp = '\Large ' . $texexp;
+       $lifetime = 86400;
+       $image  = md5($texexp) . ".gif";
+       $filetype = 'image/gif';
+       if (!file_exists("$CFG->dataroot/$CFG->algebraimagedir")) {
+          make_upload_directory($CFG->algebraimagedir);
+       }
+       $pathname = "$CFG->dataroot/$CFG->algebraimagedir/$image";
+       $windows = 0;
+         switch (PHP_OS) {
+       case "Linux":
+           $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.linux -e $pathname ". escapeshellarg($texexp);
+       break;
+       case "WINNT":
+       case "WIN32":
+       case "Windows":
+           $windows = 1;
+           $texexp = str_replace('"','\"',$texexp);
+           $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.exe -e  $pathname \"$texexp\"";
+       break;
+       case "Darwin":
+           $cmd = "$CFG->dirroot/$CFG->texfilterdir/mimetex.darwin -e $pathname ". escapeshellarg($texexp);
+       break;
+       }
+       system($cmd);
+  }
+  if ($texexp && file_exists($pathname)) {
+           $lastmodified = filemtime($pathname);
+           header("Last-Modified: " . gmdate("D, d M Y H:i:s", $lastmodified) . " GMT");
+           header("Expires: " . gmdate("D, d M Y H:i:s", time() + $lifetime) . " GMT");
+           header("Cache-control: max_age = $lifetime"); // a day
+           header("Pragma: ");
+           header("Content-disposition: inline; filename=$image");
+           header("Content-length: ".filesize($pathname));
+           header("Content-type: $filetype");
+           readfile("$pathname");
+   } else {
+           if (!$windows) {
+             $cmd = "$cmd 2>&1";
+             echo `$cmd` . "<br>\n";
+           }
+           echo "Image not found!";
+   }
+}
+?>
+
+<html>
+<head><title>Algebra Filter Debugger</title></head>
+<body>
+<?PHP
+  require_once("../../config.php");
+  $filename = "$CFG->dirroot/filter/algebra/pix.php";
+  $PHP_OS = PHP_OS;
+  $handle = fopen($filename,"r");
+  $contents = fread($handle, filesize($filename));
+  fclose($handle);
+  if (!strpos($contents,'case "'. $PHP_OS . '":')) {
+    echo "<b>WARNING!</b> case \"$PHP_OS\": NOT found in pix.php!!!<br><br>";
+  }
+?>
+    <p>Please enter an algebraic expression <b>without</b> any surrounding @@ into
+       the text box below. (Click <a href="#help">here for help.</a>)
+          <form action="algebradebug.php" method="get"
+           target="inlineframe">
+            <center>
+             <input type="text" name="algebra" size=50
+                    value="sin(z)/(x^2+y^2)">
+            </center>
+           <ol>
+           <li>First click on this button <input type="submit" name="ShowDB" value="Show DB Entry">
+               to see the cache_filters database entry for this expression.</li>
+	   <li>If the database entry looks corrupt, click on this button to delete it:
+               <input type="submit" name="DeleteDB" value="Delete DB Entry"></li>
+           <li>Now click on this button <input type="submit" name="TeXStage1" value="First Stage Tex Translation">.
+               A preliminary translation into TeX will appear in the box below.</li>
+           <li>Next click on this button <input type="submit" name="TeXStage2" value="Second Stage Tex Translation">.
+               A more refined translation into TeX will appear in the box below.</li>
+           <li>Finally click on this button <input type="submit" name="ShowImage" value="Show Image">
+               to show a graphic image of the algebraic expression.</li>
+           </ol>
+          </form> <br> <br>
+       <center>
+          <iframe name="inlineframe" align="middle" width="80%" height="200">
+          &lt;p&gt;Something is wrong...&lt;/p&gt; 
+          </iframe>
+       </center> <br>
+<hr>
+<a name="help">
+<h2>Debugging Help</h2>
+</a>
+<p>First here is a brief overview on how the algebra filter works. It
+takes an algebra expression and first translates it into TeX.  It first
+looks for the TeX translation in the Moodle database in the table cache_filters
+in the field rawtext. If not found, it passes the algebraic expression to the
+Perl script algebra2tex.pl, which also uses the Perl library AlgParser.pm.
+It then saves the TeX translation in the database for subsequent uses and
+passes the TeX to the mimetex executable to be converted to a gif image.
+Here are a few common things that can go wrong and some suggestions on how
+you might try to fix them.</p>
+<ol>
+<li>Something had gone wrong on a previous occasion when the filter tried to
+translate this expression. Then the database entry for that expression contains
+a bad TeX translation in the rawtext field (usually blank). You can fix this
+by clicking on &quot;Delete DB Entry&quot;</li>
+<li>The First Stage TeX Translation gives a &quot;No text output available&quot;
+message. If your server is running Windows, this may be due to the fact that
+you haven't installed Perl or didn't install it correctly. If your server is
+running some version of Unix (e.g. Linux), then this may be due to your Perl
+binary being installed in a nonstandard location. To fix this edit the first
+line of the algebra2tex.pl script. Another possible problem which may affect
+both Unix and Windows servers is that the web server doesn't have execute permission
+on the algebra2tex.pl script. In that case change permissions accordingly</li>
+<li>The Second Stage TeX Translation produces malformed TeX. This indicates
+a bug in the algebra filter. Post the original algebraic expression and the
+bad TeX translation in the <a href="http://moodle.org/mod/forum/view.php?id=752">
+Mathematics Tools</a> forum in the Using Moodle course on moodle.org.</li>
+<li>The TeX to gif image conversion process does not work. If your server is
+running Unix, a likely cause is that the mimetex binary you are using is
+incompatible with your operating system. You can try compiling it from the
+C sources downloaded from <a href="http://www.forkosh.com/mimetex.zip">
+http://www.forkosh.com/mimetex.zip</a>, or looking for an appropriate
+binary at <a href="http://moodle.org/download/mimetex/">
+http://moodle.org/download/mimetex/</a>. You may then also need to
+edit your moodle/filter/algebra/pix.php file to add 
+<br /><?PHP echo "case &quot;" . PHP_OS . "&quot;:" ;?><br ?> to the list of operating systems
+in the switch (PHP_OS) statement. Windows users may have a problem properly
+unzipping mimetex.exe. Make sure that mimetex.exe is is <b>PRECISELY</b>
+328192 bytes in size. If not, download fresh copy from
+<a href="http://moodle.org/download/mimetex/windows/mimetex.exe">
+http://moodle.org/download/mimetex/windows/mimetex.exe</a>. Lastly check
+the execute permissions on your mimetex binary, as outlined in item 2 above.</li>
+</ol>
+</body>
+</html>
diff --git a/filter/algebra/filter.php b/filter/algebra/filter.php
index 3d4de01d66..fdedc56574 100644
--- a/filter/algebra/filter.php
+++ b/filter/algebra/filter.php
@@ -172,7 +172,6 @@ function algebra_filter ($courseid, $text) {
               $texexp = str_replace('\mbox{acoth}','\mbox{coth}^{-1}',$texexp);
 	      $texexp = preg_replace('/\\\sqrt{(.+?),(.+?)}/s','\sqrt['. "\$2]{\$1}",$texexp);
 	      $texexp = preg_replace('/\\\mbox{abs}\\\left\((.+?)\\\right\)/s',"|\$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);
-- 
2.39.5