[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: Can XML Schemas do this?


Re:  Can XML Schemas do this?
Is the reason that we accept schemas with non-semantic required-
ordering just a matter of the tools we have to use?  DTDs make "and next" 
easy to declare but "and also" difficult.  So there is
     (a, b, c, d) 
but no
    (a && b && c && d)

Similarly there is 
    (a | b | c | d) 
but no
    (a || b || c || d) 
(meaning you can have one of these, anywhere)

I used to think this was just intrinsic to grammars (because we need to
minimise combinatorial explosions for the automaton)  but it seems the
derivation method used in some RELAX NG (brought up by Joe English)
has overcome this. 

This kind of question came up during WXS 1.0 discussions. One opinion that
came up was that it should be treated as an information-theoretic
problem: the more order we enforce, the more compressable, indexable
etc the data is.  I tend to think that is mumbo jumbo, myself:  for the
sake of flexibility, the less we encourage people build non-semantic 
constraint  into their processing software the better.  Of course,
projects with niche requirements (data serialized from legacy databases,
one-off projects with no maintenence, or high-volume systems) may
have a different trade-off. 

Cheers
Rick Jelliffe


PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
Email
First Name
Last Name
Company
Subscribe in XML format
RSS 2.0
Atom 0.3
 

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.


Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.