index.tt

Start template.

<ul>
<% FOR number IN foo  %>
<li><% number %></li>
<% END %>
</ul>

End template.

runtimetemplateconfigtest.pl

#!/usr/bin/perl

use Dancer;
set template => 'template_toolkit';

get '/' => sub {
    return template 'index', { foo => [ qw(one two three four) ] };
};

dance;