--- loncom/xml/lonxml.pm	2000/07/20 15:37:54	1.12
+++ loncom/xml/lonxml.pm	2000/07/25 21:28:22	1.13
@@ -8,6 +8,7 @@ package Apache::lonxml;
 use strict;
 use HTML::TokeParser;
 use Safe;
+use Opcode;
 
 sub register {
   my $space;
@@ -35,6 +36,7 @@ sub xmlparse {
  my $newarg = '';
  my $safeeval = new Safe;
  $safeeval->permit("entereval");
+ $safeeval->permit(":base_math");
 #-------------------- Redefinition of the target in the case of compound target
 
  ($target, my @tenta) = split('&&',$target);
@@ -87,15 +89,19 @@ sub xmlparse {
 	 }
 	 #pass both the variable to the style tag, and the tag we 
 	 #are processing inside the <definedtag>
-	 $finaloutput .= &Apache::run::evaluate($partstring,$safeeval,
+	 if ($partstring ne "" ) {
+	   $finaloutput .= &Apache::run::evaluate($partstring,$safeeval,
 		$parstack[$#parstack].$innerparstack[$#innerparstack]);
+	 }
 	 if ($tokenpat->[0] eq 'E') { pop @innerstack;pop @innerparstack; }
        }
      } else {
        my $result = &callsub("start_$token->[1]", $target, $token,\@parstack,
 			     $pars, $safeeval);
-       $finaloutput .= &Apache::run::evaluate($result,$safeeval,
-					      $parstack[$#parstack]);
+       if ($result ne "" ) {
+	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,
+						$parstack[$#parstack]);
+       }
      }              
    } elsif ($token->[0] eq 'E')  {
      #clear out any tags that didn't end
@@ -106,9 +112,6 @@ sub xmlparse {
        my @innerstack = (); 
        my @innerparstack = ();
        $newarg = $style_for_target{'/'."$token->[1]"};
-
-#       print "qqq: $token->[1],$newarg\n";
-
        my $pat = HTML::TokeParser->new(\$newarg);
        my $tokenpat;
        my $partstring = '';
@@ -132,15 +135,19 @@ sub xmlparse {
 	 }
 	 #pass both the variable to the style tag, and the tag we 
 	 #are processing inside the <definedtag>
-	 $finaloutput .= &Apache::run::evaluate($partstring,$safeeval,
+	 if ( $partstring ne "" ) {
+	   $finaloutput .= &Apache::run::evaluate($partstring,$safeeval,
 		$parstack[$#parstack].$innerparstack[$#innerparstack]);
+	 }
 	 if ($tokenpat->[0] eq 'E') { pop @innerstack;pop @innerparstack; }
        }
      } else {
        my $result = &callsub("end_$token->[1]", $target, $token, \@parstack,
 			     $pars,$safeeval);
-       $finaloutput .= &Apache::run::evaluate($result,$safeeval,
-					      $parstack[$#parstack]);
+       if ($result ne "") {
+	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,
+						$parstack[$#parstack]);
+       }
      }
      pop @stack; 
      pop @parstack;