Has anyone seen an HTML templating system that would be
usable from Ruby *AND* PHP and perhaps other languages?

So far, if you want your HTML templates to do anything
more than simple variable replacement that the template
language becomes a lot like the language it's written in.

I'm thinking particularly of Smarty (for PHP): 
http://smarty.php.net/manual/en/smarty.for.designers.php

Do you think a Ruby class could ever parse Smarty templates,
including basic 'each' logic like this:?
http://smarty.php.net/manual/en/language.function.foreach.php

Any other advice appreciated.
This is just for HTML templates, that need logic and loops,
but we might have a project that uses both Ruby and PHP,
and of course we don't want to re-write HTML templates
for each.

Thanks!