[mdaniel]

I actually tried the lxml syntax "/{urn:beta}b" and that's how I learned about the panic-based error handling, but I didn't know about that Q syntax, so thank you for bringing it to my attention

    $ echo '<a xmlns="urn:alpha">hello</a>' | xq --xpath '/Q{urn:alpha}a/text()'
    panic: /Q{urn:alpha}a/text() has an invalid token.

    goroutine 18 [running]:
    github.com/antchfx/xmlquery.Find(...)
        github.com/antchfx/xmlquery@v1.3.8/query.go:76
    ...

It seems to be a problem with that backing xmlquery library, and I did a quick GitHub topics search and found https://github.com/zzossig/rabbit which claimed to be XPath 3, but then https://github.com/zzossig/rabbit#what-is-not-supported says "lol, namespaces, wat?" so :-(

[mikmoila]

There aren't that many libraries available with full XPath 3.x conformance. In order to give some constructive feedback, perhaps an optional .conf file with ns-prefix->ns-name mappings could be read and passed to the XPath engine as ns-context? Even w/o the XPath functions support and only XPath selector expression this would make the tool to cover most of the usecases eg. simply finding elements.