--- loncom/homework/cleanxml/post_xml.pm	2016/11/10 19:48:22	1.10
+++ 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 1.10 2016/11/10 19:48:22 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/;
@@ -1858,6 +1886,18 @@ sub fix_paragraphs_inside {
           push(@new_children, $doc->createElement('p'));
         }
         $p = undef;
+        # ignore the next node if it is a br (the paragraph default margin will take as much space)
+        # (ignoring whitespace)
+        while (defined $next && $next->nodeType == XML_TEXT_NODE && $next->nodeValue =~ /^[ \t\f\n\r]*$/) {
+          my $next2 = $next->nextSibling;
+          $node->removeChild($next);
+          $next = $next2;
+        }
+        if (defined $next && $next->nodeType == XML_ELEMENT_NODE && $next->nodeName eq 'br') {
+          my $next2 = $next->nextSibling;
+          $node->removeChild($next);
+          $next = $next2;
+        }
       } elsif ($child->nodeType == XML_ELEMENT_NODE && string_in_array(\@inline_like_block, $child->nodeName)) {
         # inline_like_block: use the paragraph if there is one, otherwise do not create one
         if (defined $p) {
@@ -2034,6 +2074,20 @@ sub fix_paragraph {
               if (!defined $left || !$left_needs_p) {
                 $replacement->appendChild($middle);
               }
+              # ignore the next node if it is a br (the paragraph default margin will take as much space)
+              my $first_right;
+              if (defined $right) {
+                $first_right = $right->firstChild;
+                # ignore non-nbsp whitespace
+                while (defined $first_right && $first_right->nodeType == XML_TEXT_NODE &&
+                    $first_right->nodeValue =~ /^[ \t\f\n\r]*$/) {
+                  $first_right = $first_right->nextSibling;
+                }
+              }
+              if (defined $first_right && $first_right->nodeType == XML_ELEMENT_NODE &&
+                  $first_right->nodeName eq 'br') {
+                $right->removeChild($first_right);
+              }
             } else {
               fix_paragraphs_inside($n, $all_block);
               $replacement->appendChild($n);