RFC 6570 - URI Template
http://tools.ietf.org/html/rfc6570
Twig - The flexible, fast, and secure template language for PHP
http://www.twig-project.org
"When it comes to template languages in PHP, many people will tell you that PHP itself is a template language. But even if PHP started its life as a template language, it did not evolve like one in the recent years. As a matter of fact, it doesn't support many features modern template languages should have nowadays"