--- loncom/interface/spreadsheet/Spreadsheet.pm	2003/10/11 14:04:54	1.28
+++ loncom/interface/spreadsheet/Spreadsheet.pm	2003/11/21 21:51:28	1.31
@@ -1,5 +1,5 @@
 #
-# $Id: Spreadsheet.pm,v 1.28 2003/10/11 14:04:54 www Exp $
+# $Id: Spreadsheet.pm,v 1.31 2003/11/21 21:51:28 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -678,7 +678,7 @@ sub calc {
             return $lastcalc.': Maximum calculation depth exceeded';
         }
     }
-    return '';
+    return 'okay';
 }
 
 # ------------------------------------------- End of "Inside of the safe space"
@@ -1139,9 +1139,49 @@ sub calcsheet {
 #    $self->logthis($self->get_errorlog());
     %{$self->{'values'}} = %{$self->{'safe'}->varglob('sheet_values')};
 #    $self->logthis($self->get_errorlog());
+    if ($result ne 'okay') {
+        $self->set_calcerror($result);
+    }
     return $result;
 }
 
+sub set_badcalc {
+    my $self = shift();
+    $self->{'badcalc'} =1;
+    return;
+}
+
+sub badcalc {
+    my $self = shift;
+    if (exists($self->{'badcalc'}) && $self->{'badcalc'}) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+sub set_calcerror {
+    my $self = shift;
+    if (@_) {
+        $self->set_badcalc();
+        if (exists($self->{'calcerror'})) {
+            $self->{'calcerror'}.="\n".$_[0];
+        } else {
+            $self->{'calcerror'}.=$_[0];
+        }
+    }
+}
+
+sub calcerror {
+    my $self = shift;
+    if ($self->badcalc()) {
+        if (exists($self->{'calcerror'})) {
+            return $self->{'calcerror'};
+        }
+    }
+    return;
+}
+
 ###########################################################
 ##
 ## Output Helpers
@@ -1150,16 +1190,24 @@ sub calcsheet {
 sub display {
     my $self = shift;
     my ($r) = @_;
-    $self->compute($r);
     my $outputmode = 'html';
-    if ($ENV{'form.output_format'} =~ /^(html|excel|csv)$/) {
-        $outputmode = $ENV{'form.output_format'};
+    foreach ($self->output_options()) {
+        if ($ENV{'form.output_format'} eq $_->{'value'}) {
+            $outputmode = $_->{'value'};
+            last;
+        }
     }
     if ($outputmode eq 'html') {
+        $self->compute($r);
         $self->outsheet_html($r);
+    } elsif ($outputmode eq 'htmlclasslist') {
+        # No computation neccessary...  This is kludgy
+        $self->outsheet_htmlclasslist($r);
     } elsif ($outputmode eq 'excel') {
+        $self->compute($r);
         $self->outsheet_excel($r);
     } elsif ($outputmode eq 'csv') {
+        $self->compute($r);
         $self->outsheet_csv($r);
     }
     $self->cleanup();
@@ -1169,6 +1217,18 @@ sub display {
 ############################################
 ##         HTML output routines           ##
 ############################################
+sub html_report_error {
+    my $self = shift();
+    my $Str = '';
+    if ($self->badcalc()) {
+        $Str = '<h3 style="color:red">'.
+            &mt('An error occurred while calculating this spreadsheet').
+            "</h3>\n".
+            '<pre>'.$self->calcerror()."</pre>\n";
+    }
+    return $Str;
+}
+
 sub html_export_row {
     my $self = shift();
     my ($color) = @_;
@@ -1283,12 +1343,25 @@ sub html_header {
     my $self = shift;
     return '' if (! $ENV{'request.role.adv'});
     return "<table>\n".
-        '<tr><th align="center">'.&mt('Output Format').'</th><tr>'."\n".
-        '<tr><td>'.&output_selector()."</td></tr>\n".
+        '<tr><th align="center">'.&mt('Output Format').'</th></tr>'."\n".
+        '<tr><td>'.$self->output_selector()."</td></tr>\n".
         "</table>\n";
 }
 
+##
+## Default output types are HTML, Excel, and CSV
+sub output_options {
+    my $self = shift();
+    return  ({value       => 'html',
+              description => 'HTML'},
+             {value       => 'excel',
+              description => 'Excel'},
+             {value       => 'csv',
+              description => 'Comma Separated Values'},);
+}
+
 sub output_selector {
+    my $self = shift();
     my $output_selector = '<select name="output_format" size="3">'."\n";
     my $default = 'html';
     if (exists($ENV{'form.output_format'})) {
@@ -1296,15 +1369,12 @@ sub output_selector {
     } else {
         $ENV{'form.output_format'} = $default;
     }
-    foreach (['html','HTML'],
-             ['excel','Excel'],
-             ['csv','Comma Separated Values']) {
-        my ($name,$description) = @{$_};
-        $output_selector.=qq{<option value="$name"};
-        if ($name eq $default) {
+    foreach  ($self->output_options()) {
+        $output_selector.='<option value="'.$_->{'value'}.'"';
+        if ($_->{'value'} eq $default) {
             $output_selector .= ' selected';
         }
-        $output_selector .= ">".&mt($description)."</option>\n";
+        $output_selector .= ">".&mt($_->{'description'})."</option>\n";
     }
     $output_selector .= "</select>\n";
     return $output_selector;
@@ -1353,6 +1423,16 @@ sub create_excel_spreadsheet {
     return ($workbook,$filename);
 }
 
+#
+# This routine is just a stub 
+sub outsheet_htmlclasslist {
+    my $self = shift;
+    my ($r) = @_;
+    $r->print('<h2>'.&mt("This output is not supported").'</h2>');
+    $r->rflush();
+    return;
+}
+
 sub outsheet_excel {
     my $self = shift;
     my ($r) = @_;
@@ -1618,6 +1698,9 @@ sub set_row_numbers {
 ##
 sub exportrow {
     my $self = shift;
+    if (exists($self->{'badcalc'}) && $self->{'badcalc'}) {
+        return ();
+    }
     my @exportarray;
     foreach my $column (@UC_Columns) {
         push(@exportarray,$self->value($column.'0'));