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

Re: Entity declarations and non-validating parsers


php parameter reference

> At 12:58 PM -0500 2/23/03, Karl Waclawek wrote:
> >I don't think complete validation is possible on top of SAX.
> >AFAIR, there are a few entity related validity constraints that
> >cannot be checked through SAX.
> 
> Interesting. Looking at the spec, I only see one such validity 
> constraint that would seem to apply:

Well, All I remember was that we got a request for more detailed reporting
in Expat, since someone wanted to use it to build a DOM and to validate.
It had to do with the fact that SAX does not report the entity boundaries for:
  - general entities within attribute values 
  - parameter entities within declarations 

> Validity constraint: Entity Declared
> 
> In a document with an external subset or external parameter entities 
> with "standalone='no'", the Name given in the entity reference must 
> match that in an entity declaration. For interoperability, valid 
> documents should declare the entities amp, lt, gt, apos, quot, in the 
> form specified in 4.6 Predefined Entities. The declaration of a 
> parameter entity must precede any reference to it. Similarly, the 
> declaration of a general entity must precede any attribute-list 
> declaration containing a default value with a direct or indirect 
> reference to that general entity.
> 
> This leaves open the question of what a non-validating parser that 
> reads the DTD is supposed to do when it sees a parameter entity 
> reference before that entity is defined or an  attribute-list 
> declaration containing a default value with a direct or indirect 
> reference to a general entity which is not yet defined. My best guess 
> is that it must then start acting like a non-DTD resolving parser, 
> and not process anything that occurs after the parameter entity 
> reference, but that's just a guess.

That is actually not really trivial.
I re-wrote the WFC (not VC) Entity Declared implementation in Expat
as well as the implementation of section 5.1 of the XML 1.0 spec a while ago.
The approach taken is documented in file attachment PatchImpl.txt
for patch #578161:
http://sourceforge.net/tracker/index.php?func=detail&aid=578161&group_id=10127&atid=310127.


Karl

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.