XPath 
	JXPath
	Jaxen

JavaScript aka ECMAscript
http://www.mozilla.org/rhino/

Java Expression Library
http://galaxy.fzu.cz/JEL/

PAX
http://lists.w3.org/Archives/Public/www-dom-xpath/2000May/att-0100/01-xpathapi1.html

Ptolemy II
http://ptolemy.eecs.berkeley.edu/~eal/ee225a/lab/expression.pdf


SPEL
http://jakarta.apache.org/taglibs/doc/jsptl-doc/jsptl-ea1/spel/