use vars qw/$template/;

$template = undef;

#calls foo
foo()

#outputs page
print $template->output;

sub foo {
  $template = HTML::Template->new(filename => 'test.tmpl');

  # fill in some parameters in the template
  $template->param(home => $ENV{HOME});
  $template->param(path => $ENV{PATH});
}

##</code><code>##

our $template;

$template = undef;

#calls foo
foo()

#outputs page
print $template->output;

sub foo {
  $template = HTML::Template->new(filename => 'test.tmpl');

  # fill in some parameters in the template
  $template->param(home => $ENV{HOME});
  $template->param(path => $ENV{PATH});
}

##</code><code>##

package Page;
use HTML::Template;

sub new {
    my $class = shift;
    my $self = {};

    bless $self, $class;

    $self->setTemplate('default.tmpl');

    return $self;
}

sub setTemplate {
    my $self = shift;
    my $file = shift;

    # You really should validate the template filename here.

    $self{template} = HTML::Template->new(filename => $file);
}

sub template {
    my $self = shift;

    return $self->{template};
}

sub output {
    my $self = shift;

    return $selft->template->output;
}
1;

##</code><code>##

use Page;

my $p = Page->new;
$p->setTemplate('test.tmpl');
$p->template->param(home => $ENV{HOME});
$p->template->param(path => $ENV{path});

$p->output;