Allowing arbitrary elements as the root of a DocBook document

[David Cramer <david@thingbag.net>]

Users sometimes want to create DocBook documents such that some
arbitrary element is the root (e.g. <table>) and then xinclude that file
into a larger doc more than one time. The motivation is to avoid the
need to put an id on the element but still be able to refer to it from
an xi:include. The hitch is that if they validate this standalone file
against the DocBook schema, it's not valid because it doesn't have book,
chapter, section, etc as a root element. I've customized the schema in
the past and am about to do that again, but it makes me wonder, what is
the rational for only allowing a few elements to be the root of a
DocBook document. If I want to create a DocBook document that has
<table> or even <phrase> as its root element, why shouldn't it be
considered valid?

Regards,
David