XQL is one of those things that seemed like a good idea at the time, but it never really caught on. I don't think I've heard of anyone using it for about three years (which ties in with the date of the last release of XML::XQL).

It sounds to me like you should really think about using XPath instead.

But to answer your original question, solve returns a list of all of the nodes in your document which match your XQL query.