--- loncom/xml/run.pm	2004/02/26 23:39:04	1.45
+++ loncom/xml/run.pm	2012/12/18 18:27:43	1.61
@@ -1,6 +1,6 @@
 package Apache::run;
 #
-# $Id: run.pm,v 1.45 2004/02/26 23:39:04 albertel Exp $
+# $Id: run.pm,v 1.61 2012/12/18 18:27:43 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -46,7 +46,27 @@ while (!$_LONCAPA_INTERNAL_oldexpression
                 # only match the above if there is not { [ ( coming up
                 # Why? (I.e. this fails &a(1)[2]
                 (?=[^\[\{\(]|$)/
-         &__LC_INTERNAL_EVALUATE__($1,$2,$3)/sexg;
+		 my ($__LC__a,$__LC__b,$__LC__c)=($1,$2,$3);
+		 my $__LC__prefix;
+		 my $__LC__result;
+		 while (1) {
+		     if ($__LC__a =~ m-^&(theta|pi|rho)$-) { last; }
+		     { 
+			 use strict;
+			 no strict "vars";
+			 if (eval(defined(eval($__LC__a.$__LC__b)))) {
+			     $__LC__result= $__LC__prefix.eval($__LC__a.$__LC__b.$__LC__c);
+			     last;
+			 }
+		     }
+		     $__LC__prefix.=substr($__LC__a,0,1,"");
+		     if ($__LC__a!~m-^(\$|&|\#)-) { last; }
+		 }
+		 if (!defined($__LC__result)) {
+		     $__LC__result=$__LC__prefix.$__LC__a.$__LC__b.$__LC__c;
+		 }
+		 $__LC__result;
+                  /sexg;
     if (scalar(values(%_LONCAPA_INTERNAL_oldexpressions))>10) {last;}
 }
 ENDEVALUATE
@@ -58,19 +78,19 @@ sub evaluate {
     my $result = '';
     $@='';
     $Apache::run::timeout=0;
-    $main::SIG{'ALRM'} = sub {
+    local $main::SIG{'ALRM'} = sub {
 	$Apache::run::timeout=1;
 	die("timeout");
     };
     my $innererror;
     eval {
-	alarm($Apache::lonnet::perlvar{'lonScriptTimeout'});
+	&Apache::lonxml::start_alarm();
 	$safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
 			 "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
 	$innererror=$@;
-	alarm(0);
+	&Apache::lonxml::end_alarm();
     };
-    my $error=$@;
+    my $error=$@; 
     if ($error eq '' && $innererror eq '' && !$Apache::run::timeout) {
 	$result = $safeeval->reval('return $_;');
 	chomp $result;
@@ -80,12 +100,12 @@ sub evaluate {
 		$Apache::lonnet::perlvar{'lonScriptTimeout'}.' seconds';
 	}
 	&Apache::lonxml::error('substitution on <pre>'.
-			       &HTML::Entities::encode($expression).
+			       &HTML::Entities::encode($expression,'<>&"').
 			       '</pre> with <pre>'.
-			       &HTML::Entities::encode($decls).
+			       &HTML::Entities::encode($decls,'<>&"').
 			       '</pre> caused <pre>'.
-			       &HTML::Entities::encode($error).' '.
-			       &HTML::Entities::encode($innererror).
+			       &HTML::Entities::encode($error,'<>&"').' '.
+			       &HTML::Entities::encode($innererror,'<>&"').
 			       '</pre>');
     }
     return $result
@@ -96,16 +116,16 @@ sub run {
     my @result;
     $@='';
     $Apache::run::timeout=0;
-    $main::SIG{'ALRM'} = sub {
+    local $main::SIG{'ALRM'} = sub {
 	$Apache::run::timeout=1;
 	die("timeout");
     };
     my $innererror;
     eval {
-	alarm($Apache::lonnet::perlvar{'lonScriptTimeout'});
+	&Apache::lonxml::start_alarm();
 	@result=$safeeval->reval($code);
 	$innererror=$@;
-	alarm(0);
+	&Apache::lonxml::end_alarm();
     };
     my $error=$@;
     if (($Apache::run::timeout || $error ne '' || $innererror ne '') && !$hideerrors) {
@@ -113,15 +133,17 @@ sub run {
 	    $error = 'Code ran too long. It ran for more than '.
 		$Apache::lonnet::perlvar{'lonScriptTimeout'}.' seconds';
 	}
-	my $errormsg='<pre>'.&HTML::Entities::encode($error).' '.
-	    &HTML::Entities::encode($innererror).
-	    '</pre> occured while running <pre>';
-	$code=&HTML::Entities::encode($code);
+	my $errormsg='<pre>'.&HTML::Entities::encode($error,'<>&"').' '.
+	    &HTML::Entities::encode($innererror,'<>&"').
+	    '</pre> occurred while running <pre>';
+	$code=&HTML::Entities::encode($code,'<>&"');
 	if ($innererror=~/line (\d+)/) {
 	    my $linenumber=$1;
 	    my @code=split("\n",$code);
-	    $code[$linenumber-1]='<b><font color="red">'.
-		$code[$linenumber-1].'</font></b>';
+	    if ($linenumber < scalar(@code)) {
+		$code[$linenumber-1]='<b><font color="red">'.
+		    $code[$linenumber-1].'</font></b>';
+	    }
 	    $code=join("\n",@code);
 	}
 	&Apache::lonxml::error($errormsg.$code.'</pre>');
@@ -138,22 +160,29 @@ sub dump {
     my ($target,$safeeval)=@_;
     my $dump='';
     foreach my $symname (sort keys %{$safeeval->varglob('main::')}) {
-	if (($symname!~/^\_/) && ($symname!~/\:$/)) {
+	if (($symname!~ /^(INC|SIG)/) && ($symname!~/\027/) &&
+	    ($symname!~/^\_/) && ($symname!~/\:$/)) {
 	    my $line;
 	    if ($safeeval->reval('defined($'.$symname.')')) {
-		$line='$'.$symname.'='.$safeeval->reval('$'.$symname);
+		if ($symname =~ /^\w/) {
+		    $line.='$'.$symname.'='.$safeeval->reval('$'.$symname)."\n";
+		}
 	    }	
-	    if ($safeeval->reval('defined(@'.$symname.')')) {
-		$line='@'.$symname.'=('.
-		    $safeeval->reval('join(",",@'.$symname.')').")";
+	    if ($safeeval->reval('@'.$symname)) {
+		$line.='@'.$symname.'=('.
+		    $safeeval->reval('join(",",@'.$symname.')').")"."\n";
 	    }
-	    if ($safeeval->reval('defined(%'.$symname.')')) {
-		$line='%'.$symname.'=(';
+	    if ($safeeval->reval('%'.$symname)) {
+		$line.='%'.$symname.'=(';
 		$line.=$safeeval->reval('join(",",map { $_."=>".$'.
 					$symname.'{$_} } sort keys %'.
-					$symname.')').")"
-				    }
-	    if ($line ne '') {$dump.=&HTML::Entities::encode($line)."<br />";}
+					$symname.')').")"."\n";
+	    }
+	    if ($line ne '') {
+		$line=&HTML::Entities::encode($line,'<>&"');
+		$line=~s|\n|<br />|g;
+		$dump.=$line;
+	    }
 	}
     }
     $dump.='';
@@ -162,3 +191,29 @@ sub dump {
 
 1;
 __END__;
+
+=pod
+
+=head1 NAME
+
+Apache::run.pm
+
+=head1 SYNOPSIS
+
+Used to prevent poorly written problems from
+causing lingering after effects
+
+This is part of the LearningOnline Network with CAPA project
+described at http://www.lon-capa.org.
+
+
+=head1 NOTABLE SUBROUTINES
+
+=over
+
+=item run(), dump(), evaluate()
+
+=back
+
+=cut
+