saxon

https://github.com/fidothe/saxon-rb

Wraps the Saxon 9.9 XML and XSLT library so you can process, transform, query, and generate XML documents using XSLT 3, XQuery, and XPath 3.1. The HE open-source version is bundled, but you can use the paid-for PE and EE versions of the Java library with this gem as well. It aims to provide an idiomatic Ruby wrapper around all of Saxon's features.