--- loncom/homework/cleanxml/post_xml.pm	2016/11/10 21:53:56	1.11
+++ loncom/homework/cleanxml/post_xml.pm	2017/01/17 20:29:06	1.12
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Third step to clean a file.
 #
-# $Id: post_xml.pm,v 1.11 2016/11/10 21:53:56 damieng Exp $
+# $Id: post_xml.pm,v 1.12 2017/01/17 20:29:06 damieng Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -430,6 +430,15 @@ sub replace_m {
     my $var_key1 = 'dfhg3df54hg65hg4';
     my $var_key2 = 'dfhg654d6f5g4h5f';
     my $eval = defined $m->getAttribute('eval') && $m->getAttribute('eval') eq 'on';
+    my $display = $m->getAttribute('display');
+    if (defined $display) {
+        if ($display eq '') {
+            $display = undef;
+        }
+        if (lc($display) eq 'jsmath') {
+            $display = 'mathjax';
+        }
+    }
     if ($eval) {
       # replace variables
       foreach my $variable (@variables) {
@@ -467,6 +476,9 @@ sub replace_m {
       if ($eval) {
         $new_node->setAttribute('eval', 'on');
       }
+      if (defined $display) {
+        $new_node->setAttribute('display', $display);
+      }
       $new_node->appendChild($doc->createTextNode($new_text));
       $m->parentNode->replaceChild($new_node, $m);
       next;
@@ -497,7 +509,7 @@ sub replace_m {
     # there are math separators inside, even after hiding variables, or there was no math symbol
     
     # hide math parts inside before running tth
-    my $math_key1 = '#ghjgdh5hg45gf';
+    my $math_key1 = '#5752398247516385';
     my $math_key2 = '#';
     my @maths = ();
     my @separators = (['$$','$$'], ['\\(','\\)'], ['\\[','\\]'], ['$','$']);
@@ -528,14 +540,30 @@ sub replace_m {
       $math =~ s/&/&/g;
       $math =~ s/</&lt;/g;
       $math =~ s/>/&gt;/g;
+      my ($mel, $inside);
       if ($math =~ /^\$\$(.*)\$\$$/s) {
-        $math = '<dtm>'.$1.'</dtm>';
+        $mel = 'dtm';
+        $inside = $1;
       } elsif ($math =~ /^\\\[(.*)\\\]$/s) {
-        $math = '<dtm>'.$1.'</dtm>';
+        $mel = 'dtm';
+        $inside = $1;
       } elsif ($math =~ /^\\\((.*)\\\)$/s) {
-        $math = '<tm>'.$1.'</tm>';
+        $mel = 'tm';
+        $inside = $1;
       } elsif ($math =~ /^\$(.*)\$$/s) {
-        $math = '<tm>'.$1.'</tm>';
+        $mel = 'tm';
+        $inside = $1;
+      }
+      if (defined $inside) {
+        if ($inside =~ /^\s*$/) {
+          $math = '';
+        } else {
+          $math = '<'.$mel;
+          if ($eval && $inside =~ /$var_key1/) {
+            $math .= ' eval="on"';
+          }
+          $math .= '>'.$inside.'</'.$mel.'>';
+        }
       }
       my $replace = $math_key1.($i+1).$math_key2;
       $html_text =~ s/$replace/$math/;