- From: John Boyer <JBoyer@PureEdge.com>
- Date: Thu, 10 Feb 2005 16:16:45 -0800
- To: "Elliotte Harold" <elharo@metalab.unc.edu>
- Cc: "Robin Berjon" <robin.berjon@expway.fr>, <www-tag@w3.org>
Hi Elliotte, >John Boyer wrote: >> It might be the same bag, but it's definitely not >> the same groceries, and even she would have to >> acknowledge the increase in material. >Point taken, but why are you so convinced the namespace URI identifies >the groceries and not the bag? I accept a difference between the bag and >the groceries in the bag. It just seems more useful to me to say the URI >points to the bag, not the groceries inside it. The URI is certainly more than just a pointer to a container; it is intrinsically attached to each name in that container. The URI provides the distinguishing component in the full expanded name of an element or attribute separates that element or attribute from others that have the same local name. The direct association of the URI and each name is pervasive, not just in the namespaces rec, but also in xpath, infoset, schema and so forth. To say that the URI is meant to be attached to the actual names in every case except this one is a reach beyond the bounds of reasonable doubt at what the one sentence in the definition could possibly mean. It implies a hidden inconsistency. Heck even the grammar error in the definition leads one to believe they're talking about the names and not the container. >In your example, I see no fundamental reason why we should consider the >namespace URI to refer to the stuff in the bag rather than the bag >itself, or vice versa. Pick whichever interpretation is most useful. >more than half a decade's experience had pretty well come down on the >side that it is very problematic to use namespace URIs as a version >control mechanism, so we don't do that. How does a software module know, for example, which of two schema documents with which to load the parser if they have the same target namespaces but describe different sets of vocabulary? How is the meaning of a block of XML protected by a digital signature when the meaning can be changed without changing the serialization? What happens when an XSLT stops working in a subtle way because the schema for the namespace changed to make a required element optional or vice versa? What if the problem doesn't get noticed until 10,000 peoples' savings disappear on an otherwise sunny afternoon? Clearly there are also problems with not versioning with namespaces. Moreover, other than the claim that it is very problematic to use namespaces in version control, what's your half decade's evidence that it is? Because I've got over half a decade's experience to the contrary. It's no more problematic than writing one's vocabulary processor to say match local name plus function call to pattern match the namespace URI. In fact, the namespace change that occurs for every version of our XFDL language is the major facilitator in helping us to ensure backwards compatibility while evolving our implementations to add new features. If you have a version 6 form, it will behave identically when you run it in the version 7 processor. So, you can deploy the upgraded processor to get the new functionality for new applications without worrying about breaking the existing forms applications, which can then be upgraded only as the need arises. And why would this stop the processors in a particular domain from attempting to process documents of a higher version (albeit with reduced or erroneous functionality)? Nope, just can't figure out why some would consider wrapping antigen software around this idea when it's so much easier to just wrap a function around the check of the namespace URI. Best regards, John Boyer, Ph.D. Senior Product Architect and Research Scientist PureEdge Solutions Inc. -----Original Message----- From: Elliotte Harold [mailto:elharo@metalab.unc.edu] Sent: Thursday, February 10, 2005 11:03 AM To: John Boyer Cc: Robin Berjon; www-tag@w3.org Subject: Re: Significant W3C Confusion over Namespace Meaning and Policy John Boyer wrote: > It might be the same bag, but it's definitely not > the same groceries, and even she would have to > acknowledge the increase in material. Point taken, but why are you so convinced the namespace URI identifies the groceries and not the bag? I accept a difference between the bag and the groceries in the bag. It just seems more useful to me to say the URI points to the bag, not the groceries inside it. -- Elliotte Rusty Harold elharo@metalab.unc.edu XML in a Nutshell 3rd Edition Just Published! http://www.cafeconleche.org/books/xian3/ http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim
Received on Friday, 11 February 2005 00:17:24 UTC