--- loncom/interface/spreadsheet/assesscalc.pm	2003/07/29 05:22:56	1.17
+++ loncom/interface/spreadsheet/assesscalc.pm	2003/12/05 22:24:20	1.17.2.3
@@ -1,5 +1,5 @@
 #
-# $Id: assesscalc.pm,v 1.17 2003/07/29 05:22:56 albertel Exp $
+# $Id: assesscalc.pm,v 1.17.2.3 2003/12/05 22:24:20 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -48,6 +48,7 @@ use Apache::Constants qw(:common :http);
 use Apache::lonnet;
 use Apache::loncommon;
 use Apache::Spreadsheet;
+use Apache::loncoursedata();
 use HTML::Entities();
 use Spreadsheet::WriteExcel;
 use GDBM_File;
@@ -125,6 +126,7 @@ sub clear_package {
 
 sub initialize {
     &clear_package();
+    &Apache::loncoursedata::clear_internal_caches();
 }
 
 ########################################################
@@ -148,6 +150,7 @@ sub initialize_package {
     }
     &load_cached_export_rows();
     &load_parameter_caches();
+    &Apache::loncoursedata::clear_internal_caches();
 }
 
 ########################################################
@@ -371,6 +374,10 @@ sub parent_link {
 sub outsheet_html {
     my $self = shift;
     my ($r) = @_;
+    ####################################
+    # Report any calculation errors    #
+    ####################################
+    $r->print($self->html_report_error());
     ###################################
     # Determine table structure
     ###################################
@@ -594,7 +601,10 @@ sub compute {
         while (my ($parm,$value) = each(%parameters)) {
             last if ($self->blackout());
             next if ($parm !~ /^(parameter_.*)_problemstatus$/);
-            next if ($parameters{$1.'_answerdate'}<time);
+	    if ($parameters{$1.'_answerdate'} ne '' &&
+		$parameters{$1.'_answerdate'} < time) {
+		next;
+	    }
             if (lc($value) eq 'no') {
                 # We must blackout this sheet
                 $self->blackout(1);
@@ -738,13 +748,20 @@ sub export_data {
         ! defined($Exportrows{$symb}->{$self->{'filename'}})) {
         $self->compute();
     }
-    my @Data = @{$Exportrows{$symb}->{$self->{'filename'}}};
-    if ($Data[0] =~ /^(.*)___=___/) {
-        $self->{'sheetname'} = $1;
-        $Data[0] =~ s/^(.*)___=___//;
-    }
-    for (my $i=0;$i<$#Data;$i++) {
-        $Data[$i]="'".$Data[$i]."'" if ($Data[$i]=~/\D/ && defined($Data[$i]));
+    my @Data;
+    if ($self->badcalc()) {
+        @Data = ();
+    } else {
+        @Data = @{$Exportrows{$symb}->{$self->{'filename'}}};
+        if ($Data[0] =~ /^(.*)___=___/) {
+            $self->{'sheetname'} = $1;
+            $Data[0] =~ s/^(.*)___=___//;
+        }
+        for (my $i=0;$i<$#Data;$i++) {
+            if ($Data[$i]=~/\D/ && defined($Data[$i])) {
+                $Data[$i]="'".$Data[$i]."'";
+            }
+        }
     }
     return @Data;
 }
@@ -767,6 +784,11 @@ sub save_export_data {
     return if ($self->temporary());
     my $student = $self->{'name'}.':'.$self->{'domain'};
     my $symb    = $self->{'symb'};
+    if ($self->badcalc()){
+        # do not save data away when calculations have not been done properly.
+        delete($Exportrows{$symb});
+        return;
+    }
     if (! exists($Exportrows{$symb}) || 
         ! exists($Exportrows{$symb}->{$self->{'filename'}})) {
         return;