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Bug 2088 - R-098: must lexical form map to a value?
Summary: R-098: must lexical form map to a value?
Status: CLOSED LATER
Alias: None
Product: XML Schema
Classification: Unclassified
Component: Datatypes: XSD Part 2 (show other bugs)
Version: unspecified
Hardware: All All
: P2 normal
Target Milestone: ---
Assignee: C. M. Sperberg-McQueen
QA Contact: XML Schema comments list
URL:
Whiteboard:
Keywords: resolved
Depends on:
Blocks:
 
Reported: 2005-09-09 03:31 UTC by Sandy Gao
Modified: 2009-04-21 19:21 UTC (History)
0 users

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Description Sandy Gao 2005-09-09 03:31:12 UTC
The lexical representation of a QName has the form "prefix:localpart" 
(or "localpart"), and the value of a QName is a tuple {namespace, localpart}. 
How is a QName value converted to its canonical representation?

This problem occurs when a default/fixed attribute/element value is of type 
QName. In this case, how is it applied to the instance? For example:

<attribute name="att" type="QName" xmlns:p1="my_uri" default="p1:local"/>
If the above attribute doesn't appear in an instance, we should add a new 
attribute. But what would be the (string) value of the added attribute? (Note 
that the prefix "p1" might not be declared in the instance, or it's possible to 
be bound to a different namespace uri.)

See question 1 from:
http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001OctDec/0222.html
Comment 1 Sandy Gao 2005-09-09 03:31:56 UTC
See: http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Jan/0080.html 

The WG agreed that this is an error, will attempt to come up with a fix for 
1.0, and will definitely add it to the list of issues to consider for 1.1. In 
addition, the datatypes editors will work on text which augments "Validation 
Rule: Datatype Valid" in section 4.1.4, indicating that the lexical form must 
map to a value.
Comment 2 Sandy Gao 2005-10-06 17:06:01 UTC
The original issue is the same as that raised in bug 2103 (R-115). From the 
meeting minutes, it seems the only pending action is to augment section 4.1.4 
in the datatype spec to indicate that the lexical form must map to a value.

Changing the summary line to reflect the remaining issue.
Comment 3 Sandy Gao 2005-10-06 17:06:44 UTC
This closely relates to bug 2251 (R-259), where arguments are made against the 
proposed augmentation to 4.1.4. The WG needs to choose between one of the 2 
options:
- Stick with the decision made for R-98, mark it as needsDrafting, and close R-
259, or
- Re-open the question of whether "lexical form must map to a value", close R-
98 as overtaken by R-259.
Comment 4 Sandy Gao 2005-10-14 17:49:48 UTC
Discussed at 2005-10-07 telecon.
http://www.w3.org/2005/10/07-xmlschema-minutes.html#item07.3
Comment 5 C. M. Sperberg-McQueen 2006-09-20 23:28:22 UTC
At the face to face meeting of January 2006 in St. Petersburg,
the Working Group discussed this issue.  While there was some
regret over the decision, in the end the Working Group decided
not to take further action on this issue in XML Schema 1.1.

The rationale for the decision (as I understand it) was roughly
as follows.  This item is similar in some respects to others (bug
2200, bug 2251, bug 2075, bug 2314); all involve datatypes whose
values are in some sense correct only if appropriate declarations
(or other constructs) are in scope.  It would be good to have a
clearer account of such datatypes, but while the lack of a clear
account is highly visible in the spec, it does not seem to cause
serious problems for many people in practice.  Since we don't
seem to have any immediate prospect of achieving greater clarity,
and the problem does not seem acute for users, it seems unwise to
delay Datatypes 1.1 for further work in this area.

This issue should have been marked as RESOLVED / LATER at that
time, but apparently was not.  I am marking it that way now, to
reduce confusion.