loncom/xml/lontexconvert.pm - diff

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-version 1.43, 2005/02/11 16:46:38
+version 1.49, 2005/02/24 08:32:11
  Line 212  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)=@_;
+     # 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;
+ }
 ;
  __END__