Re: XSchema: root element

Ron Bourret (rbourret@dvs1.informatik.tu-darmstadt.de)
Thu, 2 Jul 1998 20:54:25 +0200

Chris Maden wrote:
> I would prefer
>
> Root (Useful | NotUseful) #IMPLIED
>
> Most DTDs have a number of useful potential roots and a number of
> not-so-useful ones. By providing a default value one way or the
> other, you force me to override it on a substantial portion of my
> elements.
>
> Another option is to just say that this is a suggested root:
>
> Root (Suggested) #IMPLIED
>
> For DocBook, for instance, there are many elements useful as roots,
> but I might only put Root="Suggested" on <book>'s declaration.

I am leery of IMPLIED in this case. Authoring software must decide whether to
show an element as a possible root. If a document doesn't state its preference,
the authoring software will make its own decision. Thus, two editors might
behave differently when given the same XSchema -- something I don't like.

I think that Simon's (Recommended | Possible | Forbidden) probably does the best
job here. That is, there is no technical reason most elements can't be used as
roots; it's just not always a particularly useful thing.

-- Ron Bourret