Subject: Updated issue list.
- a bunch of issues are closed, thanks to the constructive conference call. - updated the QName issue a little bit. -- Kohsuke KAWAGUCHI +1 650 786 0721 Sun Microsystems firstname.lastname@example.orgTitle: RELAX NG Issues List
RELAX NG issue list
Voted unanimously to resolve this issue by allowing elements with no declared children tp have whitespace.
"except" and "butNot" by jjc. TC is open to other suggestions.
the original post suggests to introduce syntax sugars to match frequently used wildcard patterns. Namely,
Some concerns that whether this was important enough to be worth a special syntactic abbreviation. No conclusion was reached.
This issue is merged into the "datatype and identity constraint" issue.
Decided to introduce <oneOrMoreToken> and <zeroOrMoreToken> patterns to produce list.
(a) Put a version in the RELAX NG namespace URI (by jjc)
(b) Use a version attribute on the root element (by jjc)
Input from Eric van der Vlist obtains:
He suggests to have both (a) and (b)
Input from John Cowan obtains:
He suggests to use FPI (kk: kind of URN?)
In the 5/3 telecon, we've decided to use a proposal (a). See the detail of this proposal
Input from Josh Lubell obtains:
He wants to have this because of his own experiences
Input from Kohsuke Kawaguchi obtains:
He suggests that this feature can be provided outside of the core spec (as a pre-processor like tool).
TC is still not convinved whether this feature is imporant enough to be added.
The decision is made (but tentatively) to drop this feature from version 1.
James Clark proposed to change attribute name to more sutaible one, but none is suggested by anyone.
John Cowan suggests adding optional "grammar" attribute to "ref" element and thereby introducing the ability to refer to any ancestor grammar.
TC has voted not to adopt this functionality for ver.1.0.
Various people sugges various names (including, but not limited to, TRELAX, TryRELAX, RELAXED, RELEX, REFLEX, RELAX XML Schema, TREELAX, RELAX 2, EXLAX, etc, etc.
One of the concern is whether we should include "XML Schema" in the name.
Update(May,3rd): jjc suggests "RELAX something" for various reasons (see minutes of May,3rd telecon). In response, "RELAX NG" (next generation, I guess) and RELAX++ are proposed. Other post-fixes are welcome.
Names suggested after the telecon includes URELAX, iRELAX, and TRELAX. The editor feels that RELAX NG establishes some degree of popularity.
We will use "RELAX NG" and its pronunciation will be "relaxing."
The current spec already has several restrictions that prevents problematic situations.
Some argues that the current restrictions still have something to be desired.
Currently, RELAX NG allows patterns like
<attribute name="foo"><attribute name="..." /></attribute>
<attribute name="foo"><element name="..." /></attribute>
Should we explicitly prohibits them?(original posts   ).
Those malformed patterns cannot accept anything: any RELAX NG processors can safely replace those malformed patterns by <notAllowed /> without changing semantics.
So at least it doesn't confuse processors.
Murata-san suggests to prohibit them explicitly.
Some argues that such constraints are unnecessary.
RELAX NG pattern is currently sensitive to the order of <define> element or order of <include> element because of the redefinition capability.
However, this sensitivity can be removed by restricting redefinition to only under <include> element (like XML Schema). But this restriction also limits the expressiveness of RELAX NG.
Should we introduce this restriction to make RELAX NG pattern order-insensitive language? Is this worth the cost of limiting language expressiveness?( original posts )
One of the touchstone will be XHTML modularization. kk wrote that the proposal #1 does not work and #2 does with XHTML m12n.
The proposal #3 with its amendment is adopted.
RELAX NG allows patterns like
<element name="joe"> <attribute name="foo"> ... </attribtue> <attribute name="foo"> ... </attribtue> </element>
Can we prohibit patterns like this? If so, how can we do that?( the original post )
Some people want to ban this, but no algorithm is proposed yet.
XML Schema Part 2 has capability to
But our language is also capable of doing above three.
So if we use XML Schema Part 2 as the only datatype vocabulary, we should consider dropping some of the redundant capability. (That is, restricting choices of <data>s, for example).( the original post )
jjc suggests to close this with "no-action required" because he wants to keep a distance from XML Schema Part 2.
We decided not to use the syntax of W3C XML Schema Part 2 for defining datatypes. Therefore, the overlap no longer exists.
We currently allow <grammar> elements to be nested. That is, grammar can be used just like any other patterns.
Murata-san wants to prohibit this because it may interfere with future namespace-based modularization (as currently seen in RELAX and XML Schema).( the original post )
"Namespace-based modularization" means that one module is responsible for one namespace. In my personal opinion (and probably Murata-san's), this is vital for multi-lingual validation, where multiple schema languages cooperates to validate one document.
Murata-san said he is willing to retract this if someone can convince him that nested grammar doesn't possibly interfere with such modularization.
This issue is arose by merging several issues.
The first objective was to introduce the identity constraint functionality in our new language. Then we've found that this issue is related to how our language treats datatypes.
Those posts are about possible features, but how those requirements affect the design is generally unclear. The editor believes that one thing that has developed in telcon is that we don't need any path expression if we abandon multipart keys.
In 5/3 telcon, we've made some degree of consensus about the above requirements (see minutes).
After the telcon, jjc posts his two proposals.
So now it is discovered that without greater involvement to datatypes, we can't use anonymous (or user-defined) types in key/keyref. This discovery leads to another proposal from jjc.
"datatypes #1". This post proposes how to declare new datatypes under the control of our language and how to declare key/keyref constraint.
What's important here is "under the control of our language". RELAX NG allows datatype library(DTLIB) to use its own syntax to declare new types. But in this proposal, every DTLIB is required to use the syntax of this proposal (to make type equivalence test possible).
Datatypes #2 ("the proposal of the day"). Roughly speaking, this is a simplified version of "datatypes #1", which "I(jjc) hope will be able to command consensus."
The difference with the previous proposal is that this one doesn't have the concept of "derivation". That means you can't add facets to your type once you defined it.
Kohsuke KAWAGUCHI also proposes the most simple version.
"Back to the basic" proposal. This one tries to mimic DTD's ID/IDREF capability.
The above "datatypes #2" proposal is adopted. We use the following syntax to define enumeration:
<choice> <token type="xsd:integer"> 5 </token> <token type="xsd:integer"> 2 </token> </choice>
And the following syntax to define a datatype:
<data type="xsd:integer"> <param name="minInclusive"> 5 </param> <param name="maxExclusive"> 8 </param> </data>
For many other details, see the minutes of the conference call. (Not available at this moment.)
We need a namespace URI for the new language.
jjc suggests "http://relaxng.org/ns/m.n" where m.n is the version number.
M-san suggets "http://relaxng.org/ns/something/m.n" so that we can accommodate related namespace URIs. For "something", jjc suggests "structure".
TREX allows the following pattern.
<oneOrMore> <element> ... </element> <attribute> ... </attribute> </oneOrMore>
In the computer science terminology, this is beyond the power of the "regular language". And therefore problematic for applications.
Shall we avoid this excessive expressiveness? If so, how?
In the above post, M-san suggests to restrict <oneOrMore> and <zeroOrMore> to either
jjc proposes the following restriction: "If a <oneOrMore> element has an <attribute> descendant, it must not have a <group> or <interleave> descendant."
KK suggests the following restriction: "If <group> or <interleave> is used under <oneOrMore>, then it cannot contain any <attribute>."
The TC decided to adopt the restriction by KK.
Eric van der Vlist (email@example.com)Status: open
TREX uses QName to designate datatypes and to refer to element/attribute names. But for some, use of QNames in this way is something they want to avoid.
Can we avoid using QNames? If so, shall we avoid using QNames? If so, how?
Eric proposed to declare the prefix-URI mappings in another independent way, as follows:
<namespace prefix="e" uri="http://www.w3.org/2001/XMLSchema-datatype"/> <data type="e:integer"/>
Here is the original post.
The editor believes Eric also had an alternative proposal, which write URIs every time, like this:
<data namespace="http://www.w3.org/2001/XMLSchema-datatype" type="integer"/>
Some people (including the present editor, for the full disclosure) don't like to use QName in values for some reasons, including:
On the other hand, QName is easier to write for humans, and less verbose. And some people think the use of QNames is unavoidable.
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