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Re: SVG WG Last Call review of XLink 1.1

From: Chris Lilley <chris@w3.org>
Date: Wed, 29 Mar 2006 00:52:29 +0200
Message-ID: <328644799.20060329005229@w3.org>
To: Norman Walsh <Norman.Walsh@Sun.COM>
Cc: www-xml-linking-comments@w3.org

The SVG WG is fully satisfied by your responses to all our comments. Thank you. We find the spec to be usefully improved.

On Wednesday, January 18, 2006, 11:42:21 PM, Norm wrote:

NW> / Chris Lilley <chris@w3.org> was heard to say:
NW> [...]
NW> | Therefore, the wording at
NW> | http://www.w3.org/TR/2005/WD-xlink11-20050707/#markup-reqs
NW> | is very useful:
NW> |
NW> |   "2. it does not have a type attribute from the XLink namespace and it
NW> |   adheres to the conformance constraints imposed by the XLink simple
NW> |   element type, as prescribed in this specification."
NW> |
NW> | However, this text is contradicted in several places as noted below.

NW> Thank you. Those were editorial oversights and have been corrected.

NW> | 2.1) type attribute still sometimes required
NW> |
NW> | It seems that if the href attribute is *not* supplied, which is allowed
NW> | by XLink 1.1, the type="simple" must be supplied - is that intentional?

NW> Yes.

NW> | SVG WG is okay with this restriction, if it was intended, but would
NW> | prefer not to have this restrivtion.

NW> That is the way that our note about extending XLink was worded and
NW> that is how our charter was determined.

NW> I can see your point, but requiring xlink:href or xlink:type has the
NW> virtue that it does not require applications to treat

NW>   <foo/>

NW> as if it was an xlink:type="simple" link :-). I suppose we could have
NW> chosen a different wording (something along the lines of "if any
NW> attribute from the XLink namespace is used...") but we didn't. Given
NW> that a simple link without an xlink:href is likely to be uncommon, and
NW> our goal was ease of use, this seems a reasonable compromise.

NW> | 2.2) Specification text contradictory
NW> |
NW> | 4.1 XLink Attribute Usage Patterns
NW> | http://www.w3.org/TR/2005/WD-xlink11-20050707/#d0e594
NW> |
NW> | states, for simple links
NW> |
NW> |   "At least one of type or href must be specified".
NW> |
NW> | However,
NW> |
NW> | http://www.w3.org/TR/2005/WD-xlink11-20050707/#link-types
NW> |
NW> | states
NW> |
NW> |   "The value of the type attribute must be supplied."
NW> |
NW> | We assume the latter is an editorial oversight and this should in fact be
NW> | something like:
NW> |
NW> |   The value of the type attribute must be supplied, unless a simple link
NW> |   is required and an href is supplied.

NW> Exactly.

NW> | Similarly in
NW> | http://www.w3.org/TR/2005/WD-xlink11-20050707/#simple-links
NW> |
NW> |   "The XLink element for simple links is any element with an attribute
NW> |   in the XLink namespace called type with a value of "simple""
NW> |
NW> | is incorrect and is contradicted by the example that follows it. We
NW> | suggest that it should be something like
NW> |
NW> |   The XLink element for simple links is any element with either a) an
NW> |   attribute in the XLink namespace called href and no attribute in the
NW> |   XLink namespace called type, or b) an attribute in the XLink namespace
NW> |   called type with a value of "simple".

NW> Exactly.

NW> | 2.3) DTD fragment contradicts spec
NW> |
NW> | The following DTD sample from the specification
NW> |
NW> | <!ATTLIST commandname
NW> |   xlink:type      (simple|none)   #REQUIRED
NW> |   xlink:href      CDATA           #IMPLIED>
NW> |
NW> | seems to give the impression that type is required. We suggest replacing
NW> | this with a more expressive RelaxNG snippet which states that if href is
NW> | supplied, the type attribute is optional. The relevant portion of
NW> | Appendix D may be suitable:
NW> |
NW> | simple = element * {
NW> |     (simple.type | href.att | (simple.type, href.att)),
NW> |      foreign.att*, role.att?, arcrole.att?, title.att?,
NW> |      show.att?, actuate.att?,
NW> |      (anyElement | text)*
NW> |     }

NW> Indeed. Improving the examples is on my list.

NW> | 2.4) Example incorrect in 5.2
NW> | The example with the caption
NW> |
NW> |   Example: Sample simple-Type Element Declarations and Instance
NW> |
NW> | http://www.w3.org/TR/2005/WD-xlink11-20050707/#simple-links
NW> |
NW> | is incorrect.
NW> |
NW> |   xlink:role      NMTOKEN         #FIXED
NW> "http://www.example.com/linkprops/student"
NW> |
NW> | xlink:role
NW> | E The defaultValue "http://www.example.com/linkprops/student" of
NW> | attribute "xlink:role" is not legal as for the lexical constraints of
NW> | this attribute type.
NW> |
NW> | This should be CDATA not NMTOKEN

NW> Fixed.

NW> | 3) Reserving all attributes in the XLink namespace.
NW> |
NW> | This is a useful clarification.

NW> Thank you.

NW> | 4) Allowing IRIs.
NW> |
NW> | 4.1) Inadvertent text from XLink 1.1
NW> |
NW> | In section 5.4 Locator Attribute (href)
NW> | http://www.w3.org/TR/xlink/#link-locators
NW> |
NW> |   "The value of the href attribute must be an IRI reference as defined
NW> |   in [IETF RFC 3987] or must result in an IRI reference after the
NW> |   escaping procedure described below is applied."
NW> |
NW> | That text is incorrect, and seems to be the result of a search and
NW> | replace of URI for IRI. The whole point is that the escaping is not
NW> | required in the XML instance, and is defined by the IRI specification

NW> Thanks. This text is being reworked to make all the specifications in
NW> the XML family consistent in this regard. It will be fixed in the next
NW> draft.

NW> Please let us know if you are satisfied by these resolutions to your
NW> issues.

NW>                                         Be seeing you,
NW>                                           norm





-- 
 Chris Lilley                    mailto:chris@w3.org
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Received on Tuesday, 28 March 2006 22:52:32 GMT

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