--- loncom/xml/run.pm	2001/11/07 22:29:17	1.20
+++ loncom/xml/run.pm	2002/04/10 15:22:02	1.26
@@ -1,50 +1,59 @@
 package Apache::run;
+#
+# $Id: run.pm,v 1.26 2002/04/10 15:22:02 albertel Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
 
-sub evaluateold {
-  my ($expression,$safeeval,$decls) = @_;
-# print "inside2 evaluate $decls with $expression<br />\n";
-# gerd's old method interpolates unset vars
-# $safeeval->reval('return qq('.$expression.');');
-  unless (defined $expression) { return ''; }
-  my $result = '';
-  $@='';
-  $safeeval->reval('$_=q|'.$expression.'|;');
-  if ($@ eq '') {
-    $safeeval->reval('{'.$decls.'$_=~s/(\$[A-Za-z]\w*)/(defined(eval($1))?eval($1):$1)/ge;}');
-    if ($@ eq '') {
-      $result = $safeeval->reval('return $_;');
-    } else {
-      &Apache::lonxml::error("substitution on:$expression:with:$decls:caused");
-    }
-  } else {
-    &Apache::lonxml::error("defining:$expression:caused");
-  }
-  if ($@ ne '') {&Apache::lonxml::error($@);}
-  return $result
-}
+use HTML::Entities;
 
 $Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';  
-  my %oldexpressions=();
-  while (!$oldexpressions{$_}) {
-    $oldexpressions{$_}=1;
+  my %_LONCAPA_INTERNAL_oldexpressions=();
+  my $i=0;
+  while (!$_LONCAPA_INTERNAL_oldexpressions{$_}) {
+    $_LONCAPA_INTERNAL_oldexpressions{$_}=1;
     $_ =~s/((?:\$|\&)(?:[\#|\$]*[A-Za-z][\w]*|\{[A-Za-z][\w]*\}))([\[\{][^\$\&\]\}]+[\]\}])*?(\([^\$\&\)]+\))*?(?=[^\[\{\(]|$)/eval(defined(eval($1.$2))?eval('$1.$2.$3'):'$1.$2.$3')/seg;
+    if ($i++ > 10 ) { last; }
   }
 ENDEVALUATE
 
 sub evaluate {
   my ($expression,$safeeval,$decls) = @_;
-  unless (defined $expression) { return ''; }
+  unless (defined($expression)) { return ''; }
   if (!$Apache::lonxml::evaluate) { return $expression; }
   my $result = '';
   $@='';
   $safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
 		   "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
 #  $safeeval->reval('{'.$decls.';<< &evaluate(q|'.$expression.'|);}');
+  my $error=$@;
   if ($@ eq '') {
     $result = $safeeval->reval('return $_;');
     chomp $result;
   } else {
-    &Apache::lonxml::error("substitution on:$expression:with:$decls:caused $@");
+    &Apache::lonxml::error('substitution on <pre>'.$expression.
+			   '</pre> with <pre>'.$decls.
+			   '</pre> caused <pre>'.$error);
   }  
   return $result
 }
@@ -54,9 +63,11 @@ sub run {
 #  print "inside run\n";
   $@='';
   my (@result)=$safeeval->reval($code);
-  if ($@ ne '' && !$hideerrors) {
-    &Apache::lonxml::error(":$code:caused");
-    &Apache::lonxml::error($@);
+  my $error=$@;
+  if ($error ne '' && !$hideerrors) {
+    &Apache::lonxml::error('<pre>'.&HTML::Entities::encode($error).
+			   '</pre> occured while running <pre>'.
+			   &HTML::Entities::encode($code).'</pre>');
   }
   if ( $#result < '1') {
     return $result[0];
@@ -74,11 +85,11 @@ sub dump {
       if ($safeeval->reval('defined($'.$symname.')')) {
 	$dump.='$'.$symname.'='.$safeeval->reval('$'.$symname)."\n";
       }	
-      if ($safeeval->reval('defined @'.$symname)) {
+      if ($safeeval->reval('defined(@'.$symname.')')) {
 	$dump.='@'.$symname.'=('.
 	  $safeeval->reval('join(",",@'.$symname.')').")\n";
       }
-      if ($safeeval->reval('defined %'.$symname)) {
+      if ($safeeval->reval('defined(%'.$symname.')')) {
 	$dump.='%'.$symname.'=(';
 	$dump.=$safeeval->reval('join(",",map { $_."=>".$'.
 				$symname.'{$_} } sort keys %'.