bug#20339: sxml simple: sxml->xml mishandles namespaces?

[Ricardo Wurmus]

address@hidden writes:

> What's yet missing (as far as I can read off the diff) is a way to
> "dream up" an abbreviation when it's not in the namespaces alist.

True.

Ideally, this should work even without passing a namespaces alist at all
in both "xml->sxml" and "sxml->xml".  The non-abbreviated namespaces
should not cause "sxml->xml" to fail.

Passing around a namespaces alist to both these procedures is the least
invasive approach I could think of, but I still think that it *should*
be made to work without explicitly declaring namespaces.