--- loncom/xml/run.pm	2000/09/19 18:05:21	1.6
+++ loncom/xml/run.pm	2000/11/20 17:34:05	1.13
@@ -1,20 +1,64 @@
 package Apache::run;
 
-sub evaluate {
+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 ''; }
-  $safeeval->reval('$_=\''.$expression.'\';');
-  $safeeval->reval('{'.$decls.'$_=~s/(\$\{?[A-Za-z]\w*\}?)/(defined(eval($1))?eval($1):$1)/ge;}');
-  $safeeval->reval('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 $result
+}
+
+$Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';  
+  my %oldexpressions=();
+  while (!$oldexpressions{$_}) {
+    $oldexpressions{$_}=1;
+    $_ =~s/((?:\$|\&)(?:[\#|\$]*[A-Za-z][\w]*|\{[A-Za-z][\w]*\}))([\[\{][^\$\&\]\}]+[\]\}])*?(\([^\$\&\)]+\))*?(?=[^\[\{\(]|$)/eval(defined(eval($1.$2))?eval('$1.$2.$3'):'$1.$2.$3')/seg;
+  }
+ENDEVALUATE
+
+sub evaluate {
+  my ($expression,$safeeval,$decls) = @_;
+  unless (defined $expression) { return ''; }
+  my $result = '';
+  $@='';
+  print $decls
+  $safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
+		   "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
+#  $safeeval->reval('{'.$decls.';<< &evaluate(q|'.$expression.'|);}');
+  if ($@ eq '') {
+    $result = $safeeval->reval('return $_;');
+    chomp $result;
+  } else {
+    &Apache::lonxml::error("substitution on:$expression:with:$decls:caused $@");
+  }  
+  return $result
 }
 
 sub run {
   my ($code,$safeeval) = @_;
 #  print "inside run\n";
-  $safeeval->reval($code);
+  $@='';
+  my $result=$safeeval->reval($code);
+  if ($@ ne '') { 
+    &Apache::lonxml::error(":$code:caused"); 
+    &Apache::lonxml::error($@); 
+  }
+  return $result;
 }
 
 1;