--- loncom/xml/lontexconvert.pm	2006/03/27 20:40:42	1.71
+++ loncom/xml/lontexconvert.pm	2008/02/06 10:16:00	1.87
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.71 2006/03/27 20:40:42 albertel Exp $
+# $Id: lontexconvert.pm,v 1.87 2008/02/06 10:16:00 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -42,30 +42,35 @@ package Apache::lontexconvert;
 use strict;
 use tth();
 use vars qw($errorstring);
-use Apache();
-use Apache::lonmsg();
-use Apache::lonxml();
-use Apache::lonmenu();
+#use Apache::lonxml();
 use Apache::lonlocal;
 use Apache::lonnet;
+use lib '/home/httpd/lib/perl/';
+use LONCAPA;
+ 
 
 # ====================================================================== Header
 
 sub init_tth {
     my $options=$env{'course.'.$env{'request.course.id'}.'.tthoptions'};
+    if ($options =~ /\S/) {
+	$options = ' '.$options;
+    } else {
+	undef($options);
+    }
     if ($env{'browser.mathml'}) {
 	&tth::ttminit();
 	if ($env{'browser.unicode'}) {
-	    &tth::ttmoptions('-L -u1 '.$options);
+	    &tth::ttmoptions('-L -u1'.$options);
 	} else {
-	    &tth::ttmoptions('-L -u0 '.$options);
+	    &tth::ttmoptions('-L -u0'.$options);
 	}
     } else {
 	&tth::tthinit();
 	if ($env{'browser.unicode'}) {
-	    &tth::tthoptions('-L -u1 '.$options);
+	    &tth::tthoptions('-L -u1'.$options);
 	} else {
-	    &tth::tthoptions('-L -u0 '.$options);
+	    &tth::tthoptions('-L -u0'.$options);
 	}
     }
 }
@@ -103,6 +108,14 @@ sub convert_real {
     $xmlstring=~s/^\s*\<br clear\=\"all\"/\<br/s;
     $xmlstring=~s/^\s*//;
     $xmlstring=~s/\s*$//;
+    #
+    # \rightleftharpoons is not converted by tth but maps
+    # reasonably well to &#8660;.  If we get many more of these,
+    # we're going to need to have a translation sub.
+    #
+    my $lrharpoon = pack("U", 0x21cc);
+    $xmlstring=~s/\\rightleftharpoons/$lrharpoon/g;
+
     &Apache::lonxml::end_alarm();
     return ($xmlstring,$errorstring);
 }
@@ -146,7 +159,7 @@ ENDCONV
 
 sub clean_out_math_mode {
     my ($texstring)=@_;
-    $$texstring=~s/(?!\\)\$//g;
+    $$texstring=~s/(?<!\\)\$//g;
     $$texstring=~s/\\[\)\(\]\[]//g;
     $$texstring=~s/\\ensuremath//g;
     return '';
@@ -171,25 +184,64 @@ sub jsMath_converted {
 }
 
 {
-    my $jsMath_sent_header;
+    my @jsMath_sent_header;
     sub jsMath_reset {
-	$jsMath_sent_header=0;
+	undef(@jsMath_sent_header);
+    }
+    sub jsMath_push {
+	push(@jsMath_sent_header,0);
     }
     sub jsMath_header {
-	return '' if $jsMath_sent_header;
-	$jsMath_sent_header=1;
+	if (!@jsMath_sent_header) {
+	    &Apache::lonnet::logthis("mismatched calls of jsMath_header and jsMath_process");
+	    return '';
+	}
+	return '' if $jsMath_sent_header[-1];
+	$jsMath_sent_header[-1]=1;
 	return
             '<script type="text/javascript">
                      function NoFontMessage () {}
+                     jsMath = {Parser: {prototype: {environments: {\'eqnarray*\' :[\'Array\',null,null,\'rcl\',[5/18,5/18],3,\'D\']}}}};
                    </script>'."\n".
 	    '<script type="text/javascript" src="/adm/jsMath/jsMath.js"></script>'."\n";
     }
     sub jsMath_process {
-	return '' if !$jsMath_sent_header;
-	return '<script type="text/javascript">jsMath.Process()</script>';
+	my $state = pop(@jsMath_sent_header);
+	return '' if !$state;
+	return "\n".
+	    '<script type="text/javascript">jsMath.Process()</script>'."\n";
+    }
+    sub jsMath_state {
+	my ($level) = @_;
+	return $jsMath_sent_header[$level];
     }
 }
 
+sub tex_engine {
+    if (exists($env{'form.texengine'})) {
+	return $env{'form.texengine'};
+    }    
+    if ($env{'request.course.id'}
+	&& exists($env{'course.'.$env{'request.course.id'}.'.texengine'})) {
+	return $env{'course.'.$env{'request.course.id'}.'.texengine'};
+    }
+    if (exists($env{'environment.texengine'})) {
+	return $env{'environment.texengine'};
+    }
+    return 'tth';
+}
+
+sub init_math_support {
+    my ($inherit_jsmath) = @_;
+    &init_tth();
+    &Apache::lontexconvert::jsMath_push();
+    if (lc(&tex_engine()) eq 'jsmath' ||
+	($inherit_jsmath && &jsMath_state(-2))) {
+	return &Apache::lontexconvert::jsMath_header();
+    }
+    return;
+}
+
 sub mimetex_converted {
     my $texstring=shift;
     my $displaystyle=&displaystyle($texstring);
@@ -199,7 +251,7 @@ sub mimetex_converted {
     if ($displaystyle) {
 	$$texstring='\\displaystyle \\Large '.$$texstring;
     }
-    my $result='<img src="/cgi-bin/mimetex.cgi?'.&Apache::lonnet::escape($$texstring).'" />';
+    my $result='<img src="/cgi-bin/mimetex.cgi?'.&escape($$texstring).'" />';
     if ($displaystyle) {
 	$result='<center>'.$result.'</center>';
     }
@@ -208,7 +260,7 @@ sub mimetex_converted {
 
 sub converted {
     my ($string,$mode)=@_;
-    if ($mode eq '') { $mode=$env{'environment.texengine'}; }
+    if ($mode eq '') { $mode = &tex_engine(); }
     if ($mode =~ /tth/i) {
 	return &tth_converted($string);
     } elsif ($mode =~ /jsmath/i) {
@@ -247,8 +299,8 @@ sub smiley {
 		 '\:\-(X|\#)' => 'lipsrsealed',
 		 '\:\-S' => 'huh');
     my $iconpath=$Apache::lonnet::perlvar{'lonIconsURL'};
-    foreach (keys %smileys) {
-	$expression=~s/$_/\<img src="$iconpath\/$smileys{$_}.gif" \/\>/gs; 
+    foreach my $smiley (keys(%smileys)) {
+	$expression=~s/$smiley/\<img src="$iconpath\/$smileys{$smiley}.gif" \/\>/gs; 
     }
     return $expression;
 }
@@ -259,27 +311,34 @@ sub msgtexconverted {
     &init_tth();
     my $outmessage='';
     my $tex=0;
-    foreach (split(/(?:\&lt\;|\<)\/*m\s*(?:\&gt\;|\>)/i,$message)) {
+    foreach my $fragment (split(/(?:\&lt\;|\<)\/*m\s*(?:\&gt\;|\>)/i,$message)) {
 	if ($tex) {
 	    if ($email) {
-		$outmessage.='</pre><tt>'.&to_convert($_).'</tt><pre>'; $tex=0;
+		$outmessage.='</pre><tt>'.&to_convert($fragment).'</tt><pre>';
+		$tex=0;
 	    } else {
-		$outmessage.=&to_convert($_); $tex=0;
+		$outmessage.=&to_convert($fragment);
+		$tex=0;
 	    }
 	} else {
-            $outmessage.=&smiley($_); $tex=1;
+            $outmessage.=&smiley($fragment);
+	    $tex=1;
 	}
     }
     $message=$outmessage; $outmessage=''; $tex=0;
-    foreach (split(/(?:\&lt\;|\<)\/*algebra\s*(?:\&gt\;|\>)/i,$message)) {
+    foreach my $fragment (split(/(?:\&lt\;|\<)\/*algebra\s*(?:\&gt\;|\>)/i,
+				$message)) {
 	if ($tex) {
 	    if ($email) {
-		$outmessage.='</pre><tt>'.&algebra($_,'web').'</tt><pre>'; $tex=0;
+		$outmessage.='</pre><tt>'.&algebra($fragment,'web').'</tt><pre>';
+		$tex=0;
 	    } else {
-		$outmessage.=&algebra($_,'web'); $tex=0;
+		$outmessage.=&algebra($fragment,'web');
+		$tex=0;
 	    }
 	} else {
-            $outmessage.=$_; $tex=1;
+            $outmessage.=$fragment;
+	    $tex=1;
 	}
     }
     if (wantarray) {
@@ -333,9 +392,6 @@ sub postprocess_algebra {
     # moodle had these and I don't know why, ignoring them for now
     # $string =~s/\\fun/ /g;
 
-    # remove the extra () in the denominator of a \frac
-    $string =~s/\\frac{(.+?)}{\\left\((.+?)\\right\)}/\\frac{$1}{$2}/gs;
-    
     # sqrt(3,4) means the 4 root of 3
     $string =~s/\\sqrt{([^,]+),([^\}]+)}/\\sqrt[$2]{$1}/gs;