Ampersand connector in XML

[David Megginson]

Alison Lennon writes:

 [on '&' in content models]

 > Is it likely to be included in later versions of XML? In other
 > words, what are the options for applications which need to use
 > unordered lists - SGML?

Actually, the options are somewhat broader than that.  There are two
reasons that people have traditionally wanted to use '&' in content
models:

1. to help with legacy data conversion, where the elements may be out
   of order during an intermediate stage; or

2. because there is no obvious reason to order the content.

You don't need (1), because XML allows you simply to process the
document without a DTD until it's cleaned up.  

Through more than a decade of industry experience, nearly everyone in
the SGML world ended up agreeing that (2) was a lousy idea -- the '&'
connect makes it very difficult for authors to create documents in
SGML editing tools, and as Tim Bray pointed out, the tools often got
it wrong anyway.


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

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