--- loncom/xml/lontexconvert.pm	2005/02/11 16:46:38	1.43
+++ loncom/xml/lontexconvert.pm	2005/02/24 09:58:31	1.56
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # TeX Conversion Module
 #
-# $Id: lontexconvert.pm,v 1.43 2005/02/11 16:46:38 www Exp $
+# $Id: lontexconvert.pm,v 1.56 2005/02/24 09:58:31 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -212,6 +212,72 @@ 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);
+	} else {
+	    $result = $latex;
+	}
+    } else {
+	&Apache::lonxml::error($parser->{'htmlerror'});
+    }
+}
+
+sub prepare_algebra {
+    my ($string)=@_;
+
+    # makes the decision about what is a minus sign easier supposedly
+    $string =~ s/([\=\>\<\%\!\#] *)-/$1 zeroplace -/g;
+
+    return $string;
+}
+
+sub postprocess_algebra {
+    my ($string)=@_;
+    
+    # moodle had these and I don't know why, ignoring them for now
+    # $string =~s/\\fun/ /g;
+
+    # sqrt(3,4) -> \sqrt\let{3,4\right}, which is annoying
+    $string =~s/\\left\{/\{/g;
+    $string =~s/\\right\}/\}/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;
+
+    # log(3,4) means the log base 4 of 3
+    $string =~s/\\log\\left\((.+?),(.+?)\\right\)/\\log_{$2}\\left($1\\right)/gs;
+
+    # log(3,4) means the log base 4 of 3
+    $string =~s/\\((?:sin|cos|tan|sec|csc|cot)(?:h)?)\\left\((.+?),(.+?)\\right\)/\\$1^{$3}\\left($2\\right)/gs;
+
+    # int(3,a,b) integral from a to b of 3
+    $string =~s/\\int\\left\((.+?),(.+?),(.+?)\\right\)/\\int_{$2}^{$3}\\left($1\\right)/gs;
+
+    # int( ... dx) -> ...
+    $string =~s/\\int\\left\((.+?)d[a-z]\\right\)/$1/gs;
+
+    # 
+    $string =~s/\\lim\\left\((.+?),(.+?),(.+?)\\right\)/\\lim_{$2\\to $3}$1/gs;
+    &Apache::lonnet::logthis($string);
+    return $string;
+}
 1;
 __END__