--- loncom/xml/run.pm	2005/11/15 20:50:26	1.54
+++ loncom/xml/run.pm	2012/12/18 18:27:43	1.61
@@ -1,6 +1,6 @@
 package Apache::run;
 #
-# $Id: run.pm,v 1.54 2005/11/15 20:50:26 albertel Exp $
+# $Id: run.pm,v 1.61 2012/12/18 18:27:43 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -50,6 +50,7 @@ while (!$_LONCAPA_INTERNAL_oldexpression
 		 my $__LC__prefix;
 		 my $__LC__result;
 		 while (1) {
+		     if ($__LC__a =~ m-^&(theta|pi|rho)$-) { last; }
 		     { 
 			 use strict;
 			 no strict "vars";
@@ -77,7 +78,7 @@ sub evaluate {
     my $result = '';
     $@='';
     $Apache::run::timeout=0;
-    $main::SIG{'ALRM'} = sub {
+    local $main::SIG{'ALRM'} = sub {
 	$Apache::run::timeout=1;
 	die("timeout");
     };
@@ -115,7 +116,7 @@ sub run {
     my @result;
     $@='';
     $Apache::run::timeout=0;
-    $main::SIG{'ALRM'} = sub {
+    local $main::SIG{'ALRM'} = sub {
 	$Apache::run::timeout=1;
 	die("timeout");
     };
@@ -134,13 +135,15 @@ sub run {
 	}
 	my $errormsg='<pre>'.&HTML::Entities::encode($error,'<>&"').' '.
 	    &HTML::Entities::encode($innererror,'<>&"').
-	    '</pre> occured while running <pre>';
+	    '</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>');
@@ -165,11 +168,11 @@ sub dump {
 		    $line.='$'.$symname.'='.$safeeval->reval('$'.$symname)."\n";
 		}
 	    }	
-	    if ($safeeval->reval('defined(@'.$symname.')')) {
+	    if ($safeeval->reval('@'.$symname)) {
 		$line.='@'.$symname.'=('.
 		    $safeeval->reval('join(",",@'.$symname.')').")"."\n";
 	    }
-	    if ($safeeval->reval('defined(%'.$symname.')')) {
+	    if ($safeeval->reval('%'.$symname)) {
 		$line.='%'.$symname.'=(';
 		$line.=$safeeval->reval('join(",",map { $_."=>".$'.
 					$symname.'{$_} } sort keys %'.
@@ -188,3 +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
+