[HTML]
<p>Name: <input name="address" type="text" value="" /></p>
<p>More info: <input name="more_info" type="checkbox" value="yes" /></p>

[Perl]
my ( %sql, @errors, $error, $fifvalues );

($sql{'address'}, $error ) = $self->validate( $self->query->param('address') );
   if ( $error ) { push @errors, ( { 'error' => 'Address'.$error } ); }
($sql{'more_info'}, $error ) = $self->validate($self->query->param( 'more_info') );
   if ( $error ) { push @errors, ( { 'error' => 'More info'.$error } ); }

my $template = $self->load_tmpl( 'contact.tmpl',
                                 die_on_bad_params => 0,
                               );

$template->param( errors => \@errors );

for my $key ( keys %sql ) {
   $fifvalues->{$key} = $sql{$key};
}

return $self->fill_form( \$template->output, $fifvalues );