--- loncom/xml/lontexconvert.pm	2005/02/24 01:25:05	1.45
+++ loncom/xml/lontexconvert.pm	2005/02/24 08:32:11	1.49
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.45 2005/02/24 01:25:05 albertel Exp $
+# $Id: lontexconvert.pm,v 1.49 2005/02/24 08:32:11 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -213,14 +213,18 @@ sub msgtexconverted {
 }
 
 sub algebra {
+    use AlgParser;
+
     my ($string,$target)=@_;
     my $parser = new AlgParserWithImplicitExpand;
+    $string=&prepare_algebra($string);
     my $ret = $parser->parse($string);
     my $result='['.&mt('Algebra unconverted due to previous errors').']';
     if ( ref($ret) ) {
 	$parser->tostring();
 	$parser->normalize();
 	my $latex=$parser->tolatex();
+	$latex=&postprocess_algebra($latex);
 	$latex='$'.$latex.'$';
 	if ($target eq 'web' || $target eq 'analyze') {
 	    $result = &converted(\$latex);
@@ -232,6 +236,30 @@ sub algebra {
     }
 }
 
+sub prepare_algebra {
+    my ($string)=@_;
+
+    # change some multi character operators into single character operators
+    $string =~ s/<>/\#/g;
+    $string =~ s/<\=/\%/g;
+    $string =~ s/>\=/\!/g;
+    
+    # makes the decision about what is a minus sign easier
+    $string =~ s/([\=\>\<\%\!\#] *)-/$1 zeroplace -/g;
+
+    return $string;
+}
+
+sub postprocess_algebra {
+    my ($string)=@_;
+    
+    # exapnd out some operators
+    $string =~ s/\#/\\not= /g;
+    $string =~ s/\%/\\leq /g;
+    $string =~ s/\!/\\geq /g;
+
+    return $string;
+}
 1;
 __END__