--- loncom/xml/run.pm	2002/02/15 21:33:12	1.23
+++ loncom/xml/run.pm	2002/04/10 15:22:02	1.26
@@ -1,6 +1,6 @@
 package Apache::run;
 #
-# $Id: run.pm,v 1.23 2002/02/15 21:33:12 albertel Exp $
+# $Id: run.pm,v 1.26 2002/04/10 15:22:02 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -25,33 +25,15 @@ package Apache::run;
 # 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:$expression:caused:$@:");
-  }
-  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
 
@@ -64,11 +46,14 @@ sub evaluate {
   $safeeval->reval('{'.$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
 }
@@ -78,8 +63,11 @@ sub run {
 #  print "inside run\n";
   $@='';
   my (@result)=$safeeval->reval($code);
-  if ($@ ne '' && !$hideerrors) {
-    &Apache::lonxml::error(":$@: occured while running :$code:");
+  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];