my $data_string = q{
[% foo = "bar" %]
};

use Template;
use Template::Stash;

my $stash = Template::Stash->new();
my $tmpl = Template->new(STASH => $stash);

my $out;
$tmpl->process(\$data_string, {}, \$out) or
    die $tmpl->error();

print $stash->get('foo'), "\n";