[%
   SET prev_post = undef;
   SET next_post = undef;
   FOREACH post IN posts;
     IF post.id < current;
        prev_post = post;
     ELSE;
        next_post = post;
     END;
    END -%]
[% IF next_post %]
<a href="#post-[% next_post.id %]">
    « [% next_post.title %]
</a>
[% END %]
 |
<a href="#post-list"> Main </a>
 |
[% IF prev_post %]
<a href="#post-[% prev_post.id %]">
    [% prev_post.title %] »
</a>
[% END %]