xml-processing-model-wg-charter.html
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<title>XML Processing Model Working Group Charter</title>
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<h1>Charter of the XML Processing Model Working Group</h1>
<p><strong style="background-color: red">Superseded by <a href="http://www.w3.org/XML/2009/02/xproc-charter.html">a new charter</a> in February 2009.</strong></p>
<p><strong>[October 2005]</strong></p>
<address>Norman Walsh, Sun Microsystems, Chair
<br/>
Henry Thompson and C. M. Sperberg-McQueen, Team Contacts</address>
<p><em>The XML Processing Model Working Group is a Working Group of
the W3C and follows the Working Group process described in section
<a href="http://www.w3.org/2005/10/Process-20051014/groups.html#GroupsWG">6.2
Working Groups and Interest Groups</a> of the <a href="http://www.w3.org/Consortium/Process">Process Document</a>. Except
as specified in this charter, the Working Group follows the
<a href="http://www.w3.org/2003/09/xmlap/xml-common-proc.html">Common
Procedures for XML Working Groups</a>.</em></p>
</div>
<hr/>
<div>
<h3 class="toc">Table of Contents</h3>
<ol>
<li><a href="#xml-scope">Scope</a></li>
<li><a href="#Deliverables">Deliverables</a></li>
<li><a href="#Schedule">Schedule</a></li>
<li><a href="#Duration">Duration</a></li>
<li><a href="#x-rel">Relationship with Other Activities</a></li>
<li><a href="#WGmembership">Working Group participation</a></li>
<li><a href="#AEN124">Meetings</a></li>
<li><a href="#AEN117">Communication</a></li>
<li><a href="#Confident">Confidentiality</a></li>
<li><a href="#pp">Patent Policy</a></li>
<li><a href="#HowToJoin">How to Join the Working Group</a></li>
</ol>
</div>
<hr/>
<div>
<h2 id="xml-scope">Scope</h2>
<p>The XML Specification defines an interchange format for
structured information, but does not define how that format is to
be used. Other specifications, such as XSLT, XML Schema, XInclude
and XML Canonicalization define transformations that operate on and
produce XML documents. The order in which these transformations are
to be applied is not specified anywhere, even though applying them
in different orders will in general yield different results.</p>
<p>The ability to specify the order, parameters, and expected
results of such transformations in a standard way would be highly
beneficial for interoperability between systems using different
sets of processors for these transformations.</p>
<p>Two distinct perspectives can be identified: A scripting
perspective, in which an independent XML document specifies the
sequence of operations to be performed, and a self-describing
perspective, in which a document is understood as signalling its
own processing.</p>
<p>With respect to the scripting perspective, the group should
define a language in which this can be expressed. This XML
Processing <em>language</em> should allow users to specify the
pipeline processing of XML documents, for example using multiple
XSLT stylesheets as part of general data processing with XML.</p>
<p>With respect to the self-describing perspective, the existing
XML specifications which define transformations are manifested in
XML documents in many different ways, including the document
element (<code>xenc:EncryptedData</code>), internal elements
(<code>xi:include</code>), processing instructions
(<code><?xml-stylesheet…?></code>) and attributes
(<code>xsi:schemaLocation</code>). When encountering an XML
document including some of these features, a general-purpose
processor currently has no guidance as to which, if any, of the
corresponding transformations should actually be applied. So, for
example, a reference to part of a document may be ambiguous as to
whether the reference is applied before or after transformation.
The group will investigate and illuminate this issue.</p>
<p>The XML Processing Model Working Group will explore whether an
XML-based system can determine whether the creator of any given XML
document has indicated that operations on that document should be
performed in a specific order for a particular result, and if so,
how to apply those operations. This might take the form of
reference to an external document in the XML Processing language,
or some form of annotation regarding the self-describing aspects of
the document. There is however no expectation that all documents
will provide either form of indication, nor is there any
expectation that such an XML Processing <em>model</em> as the WG
produces will be the only way anyone will process XML
documents.</p>
<p>The Working Group will take as input <a href="http://lists.w3.org/Archives/Member/xml-pm-ws/">the position
papers</a> (<a href="http://cgi.w3.org/MemberAccess/">Members-only</a>) of the <a href="http://www.w3.org/XML/2001/07/XMLPM.html">W3C Workshop on the XML
Processing Model</a> as well as the two related W3C Member
Submissions (<a href="http://www.w3.org/TR/2002/NOTE-xml-pipeline-20020228/">XML
Pipeline Definition Language Version 1.0</a> and <a href="http://www.w3.org/Submission/xpl/">XML Pipeline Language (XPL)
Version 1.0</a>), and any other work in the area that the Working
Group considers to be relevant.</p>
<p>As suggested above, the primary focus of the Working Group will
be managing XML processing at the whole-document level, where each
step in the processing of a document can be seen as a
transformation as defined by a particular W3C Recommendation or
comparable specification.</p>
<h3 class="sub" id="Goals">Goals</h3>
<p>The goals of the XML Processing Model Working Group are to
develop two Recommendation Track documents:</p>
<ol>
<li>An XML Processing Language which answers the following
questions:
<ol>
<li>What is to be done to a given document or a set of documents by
a given sequence of given XML processors?</li>
<li>Which data model (XML Information Set, PSVI, XPath 1.0, XQuery
1.0 and XPath 2.0) is manipulated by each transformation
process?</li>
<li>How are exceptions handled during processing?</li>
<li>What is the expected outcome after processing?</li>
</ol>
</li>
<li>An XML Processing Model which answers the following questions:
<ol>
<li>Which if any of the transformations signalled by aspects of an
XML document should be performed, and in what order? Examples of
transformations include, but are not limited to, XInclude, XML
Canonicalization (and/or Exclusive Canonicalization), XSLT, xml:id,
XML Signature and XML De/Encryption.</li>
<li>How can an author, consumer, or application guide this
process?</li>
<li>In the absence of any guidance, what default processing, if
any, should be done in what circumstances?</li>
<li>What will the impact of a default processing model be on
existing XML documents and processors, in particular DOM
implementations?</li>
</ol>
</li>
</ol>
<p>It is also expected that the Working Group will take into
consideration potential consequences of processing XML documents
represented by alternative (e.g. efficient XML interchange)
serializations, or bundled together as compound documents or with
other packaging methods.</p>
<p>Any specification of processing inevitably raises security
issues: the Working Group will seek input on this from relevant
sources of expertise inside and, if appropriate, outside the
W3C.</p>
<div>
<h2 id="Deliverables">Deliverables</h2>
<ol>
<li>A Requirements document for an XML Processing Language</li>
<li>A Use Cases document for an XML Processing Language (this may
be incorporated into the Requirements document)</li>
<li>A Requirements document for an XML Processing Model</li>
<li>A Use Cases document for an XML Processing Model (this may be
incorporated into the Requirements document)</li>
<li>A W3C Recommendation for an XML Processing Language, to express
a specific set of pipelined operations to be applied to a
document.</li>
<li>A W3C Recommendation for an XML Processing Model that will
address the goals given above</li>
</ol>
</div>
<div>
<h2 id="Schedule">Schedule</h2>
<p>The two main goals of the WG are clearly related, and will be
pursued in parallel, but the situation with respect to the XML
Processing Language is much further advanced, with a number of
systems already in use. Accordingly a more aggressive timetable
will be possible for that goal, which is expected to draw heavily
on already deployed and widely-used systems. The questions
surrounding the XML Processing Model are more complex, and may
require more extended exploration and discussion before a
conclusion is reached.</p>
<dl>
<dt>2 months</dt>
<dd>XML PL First Public Working Draft of Use Cases and Requirements
(A first working draft was already made by the XML Core Working
Group; the XML Processing Model Working Group should, however,
start by making new Requirements and Use Cases documents, reusing
as much of the existing draft as possible consistent with consensus
within the Working Group.)</dd>
<dt>4 months</dt>
<dd>XML PL First Public Working Draft</dd>
<dt>6 months</dt>
<dd>XML PL Last Call Working Draft; XML PM First Public Working
Draft of Use Cases and Requirements</dd>
<dt>9 months</dt>
<dd>XML PL Candidate Recommendation; XML PM First Public Working
Draft</dd>
</dl>
<p>The XML Processing Model Specifications are expected to go
through Last Call Working Draft and reach Candidate Recommendation
or Recommendation during the lifetime of this Charter, but
milestones after the first Public Working Drafts may need to be
adjusted in the light of the reaction to the draft documents both
from other Working Groups and from the public.</p>
</div>
<div>
<h2 id="Duration">Duration</h2>
<p>The original expiration date of this charter was 31 October 2007 -- it
<a href="http://lists.w3.org/Archives/Member/w3c-ac-members/2007OctDec/0012.html">was extended</a> (Member-only link) to 31 October 2008.</p>
</div>
<div>
<h2 id="x-rel">Relationship with Other
Activities</h2>
<p>The deliverable of the XML Processing Model Working Group must
satisfy the dependencies from other W3C Working Groups. The list
here must be reviewed by the Working Group and the W3C Team after
the Use Cases and Requirements are published.</p>
<dl>
<dt>The <a href="http://www.w3.org/Style/XSL/">XSL Working
Group</a></dt>
<dd>
<p>XSLT is a commonly used transformation mechanism, and XSL-FO a
frequent (and the original intended) target of such
transformations.</p>
</dd>
<dt>The <a href="http://www.w3.org/XML/Group/Query">XML Query
Working Group</a></dt>
<dd>
<p>The XML Query Language can be used to select data from arbitrary
collections of XQuery 1.0 and XPath 2.0 Data Model instances; the
XQuery 1.0 and XPath 2.0 Data Model specification is maintained
jointly by the XSL and XML Query Working Groups, and is a possible
starting point for an XML Processing Model.</p>
</dd>
<dt>The <a href="http://www.w3.org/XML/Group/Schemas">XML Schema
Working Group</a></dt>
<dd>
<p>A W3C XML Schema document can provide default document content
which could (for example by introducing XInclude directives or
default attribute values) substantially affect the results of other
transformations.</p>
<p>The XML Processing Model must interact in a well-defined manner
with the PSVI.</p>
</dd>
<dt>The <a href="http://www.w3.org/XML/Group/Core">XML Core Working
Group</a></dt>
<dd>
<p>The XML Processing Model Specification was originally within the
scope of the XML Core Working Group, and was taken out for
logistical reasons.</p>
<p>Interactions with core specifications such as xml:base and
XInclude must be carefully reviewed.</p>
</dd>
<dt>DOM and Web Applications</dt>
<dd>
<p>Any suggested default XML processing model would need to be
carefully checked for impact on the work of these groups.</p>
</dd>
<dt>The Technical Architecture Group</dt>
<dd>
<p>The work on default behaviors for the XML Processing Model will
need coordination with the TAG. The XML Processing Model should
also be aligned with the <a href="http://www.w3.org/TR/webarch/">Web Architecture</a>, including the
role of Internet media types.</p>
</dd>
</dl>
<p>Formal liaison between the XML Processing Model Working Group
and other W3C Working Groups, as well as organizations outside of
the W3C, shall normally be accomplished through the XML
Coordination Group.</p>
</div>
<div>
<h2 id="WGmembership">Working Group
Participation</h2>
<p>Participation is expected to consume up to one day per week of
each participant’s time, although the time commitment for the chair
and editors may be higher.</p>
<p>The level of participation expected for this Working Group
suggests that representatives be experts in the development and use
of XML-related specifications.</p>
<div>
<h3 class="sub" id="Chairs">Chair</h3>
<p>The initial Chair of the XML Processing Model Working Group is
Norman Walsh.</p>
<h3 class="sub" id="W3CResources">W3C Team
resources</h3>
<p>The initial W3C Team contacts for this Working Group are Henry
S. Thompson and C. M. Sperberg-McQueen.</p>
<p>It is expected that this Working Group would consume about 0.4
FTE, including administrative logistics.</p>
</div>
</div>
<div>
<h2 id="AEN124">Meetings</h2>
<p>The Working Group will have weekly teleconferences. Face-to-face
meetings will be held as needed.</p>
</div>
<div>
<h2 id="AEN117">Communication</h2>
<p>The XML Processing Model Working Group shall communicate among its
participants using the <code><a href="http://lists.w3.org/Archives/Public/public-xml-processing-model-wg">public-xml-processing-model-wg</a></code>
publicly-readable mailing list and with the other XML Working Groups
through the <a href="http://lists.w3.org/Archives/Member/w3c-xml-plenary"><tt>w3c-xml-plenary</tt></a>
mailing list. Both lists are archived.</p>
<p>Public comment on the work of the XML Processing Model Working
Group may be submitted via the <a href="http://lists.w3.org/Archives/Public/public-xml-processing-model-comments/">public-xml-processing-model-comments</a> public mailing list.</p>
</div>
<div>
<h2 id="Confident">Confidentiality</h2>
<p>The proceedings of this working group are publicly readable,
subject to exceptions made by the chair. In particular, the archive
of the mailing list used for technical discussion and the Group
home page are publicly readable.</p>
</div>
<div>
<h2 id="pp">Patent Policy</h2>
<p>This Working Group operates under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">W3C Patent
Policy</a> (5 February 2004 Version). To promote the widest
adoption of Web standards, W3C seeks to issue Recommendations that
can be implemented, according to this policy, on a Royalty-Free
basis.</p>
</div>
<h2 id="HowToJoin">How to Join the Working
Group</h2>
<p>Information about how to join the Working Group is available on a
separate <a href="http://www.w3.org/2004/01/pp-impl/38398/join">“How-to-Join
page”</a>.</p>
<hr/>
<address>Liam Quin, XML Activity Lead<br/>
Last modified $Date: 2010/03/02 13:37:46 $</address>
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