> PIs are extremely useful when adding information to documents with
> frozen DTDs. For example, the proposed "xml:stylesheet" PI allows you
> to attach a stylesheet to any XML document without having to
> tamper with the document's DTD (as by adding a STYLE element
> or attribute).
>
> I can't see designing a new document type and using PIs, though.
> As you say, elements or attributes do the work.
PI's provide a (slightly clumsy) method for adding new declaration
types to XML without breaking existing parsers. In general, I don't
think that it's a good idea to use elements and attributes for
declarations, since they represent the logical structure of the
document itself.
All the best,
David
--
David Megginson david@megginson.com
http://www.megginson.com/