Re: Define a root in a DTD

["Thomas B. Passin" <tpassin@home.com>]

[Bob DuCharme]
> This is a Good Thing, because it adds flexibility to how the DTD is used.
> It's the reason that XML (and SGML) have lent themselves so well to
> electronic publishing systems in which different elements were mixed and
> matched to create different documents all conforming to the same DTD.
>
It is a Good Thing, yet it can cause difficulty too.  I'm thinking of an
xml-schema describing a set of, say, 30 top-level messages.  There could be
many more global elements than that, depending on how the schema was
written.  You only want to write your processor to support the intended 30
messages (i.e., top-level elements), not every possible combination.  But
you can't express this in the schema itself.

You could achieve this result if you make sure that the intended top-level
elements are the only global ones, but if it's not your own schema you might
not be sure.

Cheers,

Tom P