You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
102 lines
7.7 KiB
102 lines
7.7 KiB
|
|
<!DOCTYPE html
|
|
PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html lang="en"><head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>Extending XLink 1.0 </title><style type="text/css">
|
|
code { font-family: monospace; }
|
|
|
|
div.constraint,
|
|
div.issue,
|
|
div.note,
|
|
div.notice { margin-left: 2em; }
|
|
|
|
ol.enumar { list-style-type: decimal; }
|
|
ol.enumla { list-style-type: lower-alpha; }
|
|
ol.enumlr { list-style-type: lower-roman; }
|
|
ol.enumua { list-style-type: upper-alpha; }
|
|
ol.enumur { list-style-type: upper-roman; }
|
|
|
|
|
|
div.exampleInner pre { margin-left: 1em;
|
|
margin-top: 0em; margin-bottom: 0em}
|
|
div.exampleOuter {border: 4px double gray;
|
|
margin: 0em; padding: 0em}
|
|
div.exampleInner { background-color: #d5dee3;
|
|
border-top-width: 4px;
|
|
border-top-style: double;
|
|
border-top-color: #d3d3d3;
|
|
border-bottom-width: 4px;
|
|
border-bottom-style: double;
|
|
border-bottom-color: #d3d3d3;
|
|
padding: 4px; margin: 0em }
|
|
div.exampleWrapper { margin: 4px }
|
|
div.exampleHeader { font-weight: bold;
|
|
margin: 4px}
|
|
</style><link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/W3C-WG-NOTE.css"></head><body><div class="head"><p><a href="http://www.w3.org/"><img src="http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72"></a></p>
|
|
<h1><a name="title" id="title"></a>Extending XLink 1.0 </h1>
|
|
<h2><a name="w3c-doctype" id="w3c-doctype"></a>W3C Working Group Note 27 January 2005</h2><dl><dt>This version:</dt><dd>
|
|
<a href="http://www.w3.org/TR/2005/NOTE-xlink10-ext-20050127/">http://www.w3.org/TR/2005/NOTE-xlink10-ext-20050127/</a>
|
|
</dd><dt>Latest version:</dt><dd>
|
|
<a href="http://www.w3.org/TR/xlink10-ext/">http://www.w3.org/TR/xlink10-ext/</a>
|
|
</dd><dt>Editor:</dt><dd>Norman Walsh, Sun Microsystems</dd></dl><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2005 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.org/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p></div><hr><div>
|
|
<h2><a name="abstract" id="abstract"></a>Abstract</h2><p>This document describes some useful changes that could be incorporated
|
|
into an XLink 1.1 Specification.</p></div><div>
|
|
<h2><a name="status" id="status"></a>Status of this Document</h2><p><em>This section describes the status of this document at the time
|
|
of its publication. Other documents may supersede this document. A
|
|
list of current W3C publications and the latest revision of this
|
|
technical report can be found in the
|
|
<a href="http://www.w3.org/TR/">W3C technical reports index</a>
|
|
at http://www.w3.org/TR/.</em></p><p>This document is a
|
|
<a href="http://www.w3.org/2004/02/Process-20040205/tr.html#WGNote">W3C
|
|
Working Group Note</a>, made available by the
|
|
<a href="http://www.w3.org/XML/Core">W3C XML Core Working Group</a>
|
|
as part of the
|
|
<a href="http://www.w3.org/XML/Activity">XML Activity</a>.
|
|
The authors of this document are the XML Core Working
|
|
Group participants.</p><p>This WG Note is being published for information purposes only.
|
|
The Working Group does not plan to issue updates and therefore
|
|
has no current plans or process by which to handle feedback.</p><p>Publication as a Working Group Note does not imply endorsement by the W3C
|
|
Membership. This is a draft document and may be updated, replaced or
|
|
obsoleted by other documents at any time. It is inappropriate to cite this
|
|
document as other than work in progress.</p></div><div class="toc">
|
|
<h2><a name="contents" id="contents"></a>Table of Contents</h2><p class="toc">1 <a href="#intro">Introduction</a><br>
|
|
1.1 <a href="#changes">Proposed Changes</a><br>
|
|
</p>
|
|
<h3><a name="appendices" id="appendices"></a>Appendix</h3><p class="toc">A <a href="#references">References</a><br>
|
|
</p></div><hr><div class="body"><div class="div1">
|
|
<h2><a name="intro" id="intro"></a>1 Introduction</h2><p>Since its introduction as a Recommendation,
|
|
<a href="#xlink">[XLink]</a> has been adopted
|
|
by several markup vocabularies. However, the current trend to migrate
|
|
from DTD-based validation to schema-based validation poses additional
|
|
challenges that could hamper its continued adoption.</p><p>A few small changes could:</p><ul><li><p>Make XLink easier to use.</p></li><li><p>Reduce its dependence on annotations provided by external grammars
|
|
(XML DTDs or XML Schema, for example)</p></li><li><p>Increase interoperability by reducing the risk of markup errors or
|
|
misinterpretations.</p></li></ul><div class="div2">
|
|
<h3><a name="changes" id="changes"></a>1.1 Proposed Changes</h3><ol class="enumar"><li><p><em>Make simple XLinks an application-level default.</em></p><p>In XLink 1.0, all simple links must be identified explicitly with
|
|
an <code>xlink:type</code> attribute. When XLink 1.0 was developed, it
|
|
seemed reasonable to depend on DTD validation to provide this default
|
|
value when it was a burden to authors to enter it by hand. As XML use
|
|
has spread and new validation technologies have been developed, this
|
|
is no longer the case.</p><p>Rather than relying on an annotation to provide the simple link
|
|
type, it seems prudent to make this an application-level default. In
|
|
other words, any element with an <code>xlink:href</code> attribute that
|
|
does not specify a link type should be treated as a simple link.</p></li><li><p><em>Reserve all attributes in the XLink namespace.</em></p><p>The current XLink 1.0 Recommendation defines several attributes
|
|
in the XLink namespace. It seems prudent to explicitly reserve all
|
|
other such attributes for future use. By a strict interpretation of
|
|
the current specification, authors and other end-users have free
|
|
latitude to use new attributes in the XLink namespace and this was
|
|
never intended. Such use would create interoperability problems and
|
|
should be prohibited.</p></li><li><p><em>Allow IRIs.</em></p><p>The current specification requires that URIs be used to identify
|
|
some XLink properties, such as role and arc types. In the interest of
|
|
forward compatibility, these requirements should be amended so that
|
|
IRIs are also allowed.</p></li><li><p><em>Provide Sample XML Schema and RELAX NG Grammars.</em></p><p>The current specification provides a non-normative sample DTD.
|
|
Given that XML Schema
|
|
and RELAX NG are now widely deployed, it makes sense to provide equivalent,
|
|
non-normative XML Schema and RELAX NG Grammars.</p></li></ol><p>XLink is not without its critics and it's clearly the case that
|
|
these changes do not address all of the criticisms that have been
|
|
leveled at XLink. But these changes would make XLink more useful in
|
|
the places where it is <em>already</em> being used and would
|
|
make XLink practical in a variety of similar vocabularies.</p></div></div></div><div class="back"><div class="div1">
|
|
<h2><a name="references" id="references"></a>A References</h2><dl><dt class="label"><a name="xlink" id="xlink"></a>XLink</dt><dd><a href="http://www.w3.org/TR/xlink/"><cite>XML
|
|
Linking Language (XLink) Version 1.0</cite></a>. DeRose, Steve, Eve Maler,
|
|
and David Orchard, editors. World Wide Web Consortium, 2001. (See http://www.w3.org/TR/xlink/.)</dd></dl></div></div></body></html>
|