HTML::Template Modules and Zeros

Angel has asked for the wisdom of the Perl Monks concerning the following question:

Dear Fellow Monks,

Back when I was doing simple subtitution s/var_name/$var_name I used a pad function to take the results from a database that were zero but perl insisted were blank scalars and print them as "0"

I am now using HTML::Template and using a Module to query the data my attempts have failed to get "0" on the output. Any ideas I am sure its simple but I have missed something here. And I'd rather not put the padding in the main module

# pad adds leading zeros to a string

### FROM THE MODULE THAT QUERIES THE DATA ####

sub pad( )
{
   my $output;

   my ($string, $length)=@_;
        
   if( $string eq "" )
    {
       $output = "0";

    }
   else
   {
       my $padlength=$length-length($string);
      $output = "0"x$padlength.$string;

   }

   return $output;

} 



sub get_number_prereg_adult( $ )
{
   my $data;
   my $query;    

   my $self = shift;

   my $dbh  = $self->{dbh};    
    

     my $sqlQuery = "SELECT COUNT(*)
                      FROM PREREGDATA
                     WHERE GroupID  = $self->{'group_id'}
                       AND Category = \'1\'";
                        
   $query = $dbh->prepare( $sqlQuery );
     
   $query->execute() || die $dbh->errstr;
   
   if( $data = $query->fetchrow_array() )
   {        
       $self->{error_type}   = "";   
       $self->{error_string} = "";
       return( pad( $data, 1 ) );

   }
   else
   {
       $self->{error_type}   = "variable returned no value";   
       $self->{error_string} = "variable returned no value";    
       return( undef ); 
   }    
   
}


### FROM THE MODULE THAT USES HTML TEMPLATE

   #set template page
   $template = HTML::Template->new( filename=>"update_group_informatio
+n_template.htm" );
    


                            
                            
    $template->param( number_pre_reg_adult_variable_string      => $qu
+ery_module->get_number_prereg_adult   );
[download]

Comment on HTML::Template Modules and Zeros Download Code

Replies are listed 'Best First'.
Re: HTML::Template Modules and Zeros by dws (Chancellor) on Apr 22, 2003 at 00:19 UTC
Any ideas? I am sure its simple but I have missed something here. When in doubt, write a short test. `use HTML::Template; # version 2.6 my @template = <DATA>; my $template = HTML::Template->new(arrayref => \@template); $template->param(ZERO => 0); $template->param(ONE => 1); print $template->output(); __DATA__ Zero = <TMPL_VAR ZERO> One = <TMPL_VAR ONE>` [download] produces the expected result `Zero = 0 One = 1` [download] You might have run into a version-dependent bug, or you might have a problem upstream. What happens when you try to replicate the problem with a small example? Update: jeffa points out that `my $template = HTML::Template->new(filehandle => *DATA);` is another way to go.	[reply] [d/l] [select]
Re: HTML::Template Modules and Zeros by dragonchild (Archbishop) on Apr 21, 2003 at 22:39 UTC
This may not mean much, but: `if( $data = $query->fetchrow_array() )` [download] is suspect to me. It will always, in this case, give you zero or 1. I suspect you want: `if( ($data) = $query->fetchrow_array() )` [download] That may not fix your problem, but it is a bug. ------ We are the carpenters and bricklayers of the Information Age. Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement. Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.	[reply] [d/l] [select]
(z) Re: HTML::Template Modules and Zeros by zigdon (Deacon) on Apr 22, 2003 at 17:20 UTC
Is it possible that your output template has something like this? `<TMPL_IF number_pre_reg_adult_variable_string> the output is <TMPL_VAR number_pre_reg_adult_variable_string> </TMPL_IF>` [download] If so, the block won't print because the variable is evalurating to 0! -- zigdon	[reply] [d/l]