Another abandoned server code base... this is kind of an ancestor of taskrambler.
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<h1><a name="title" id="title"></a>XPath Requirements
Version 2.0</h1>
<h2>W3C Working Draft 3 June 2005</h2>
<dl>
<dt>This version:</dt>
<dd><a href="http://www.w3.org/TR/2005/WD-xpath20req-20050603/">http://www.w3.org/TR/2005/WD-xpath20req-20050603/</a></dd>
<dt>Latest version:</dt>
<dd><a href="http://www.w3.org/TR/xpath20req/">http://www.w3.org/TR/xpath20req/</a></dd>
<dt>Previous versions:</dt>
<dd><a href="http://www.w3.org/TR/2003/WD-xpath20req-20030822">http://www.w3.org/TR/2003/WD-xpath20req-20030822</a></dd>
<dd><a href="http://www.w3.org/TR/2001/WD-xpath20req-20010214">http://www.w3.org/TR/2001/WD-xpath20req-20010214</a></dd>
<dt>Editors:</dt>
<dd>Mary Fernandez (AT&amp;T) <a href="mailto:mff@research.att.com">mff@research.att.com</a></dd>
<dd>K Karun (Oracle) <a href="mailto:K.Karun@oracle.com">K.Karun@oracle.com</a></dd>
<dd>Mark Scardina (Oracle) <a href="mailto:Mark.Scardina@oracle.com">Mark.Scardina@oracle.com</a></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>
<hr title="Separator for header" />
</div>
<h2><a name="abstract" id="abstract">Abstract</a></h2>
<p>This document describes the requirements for the XPath 2.0
specification and is annotated with their resolution in <a href="#XPath2">[XPath 2.0]</a> or <a href="#XPathFO">[XQuery 1.0 and
XPath 2.0 Functions and Operators]</a> and the <a href="#XQDM">[XQuery 1.0 and XPath 2.0 Data Model]</a>
specifications.</p>
<h2><a name="status" id="status">Status of this document</a></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 includes, for each
requirement, a corresponding status, indicating the current situation
of the requirement in the XPath 2.0 family of specifications at the
time that they are being issued as Last Call Working Drafts in April, 2005.</p>
<p>This is a W3C Working Draft for review by W3C Members and
other interested parties. Publication as a Working Draft 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>
<p>This document has been defined jointly by the <a href="http://www.w3.org/Style/XSL/">XSL Working Group</a> and the
<a href="http://www.w3.org/XML/Query">XML Query Working Group</a>
(both part of the <a href="http://www.w3.org/XML/Activity.html">XML Activity</a>).</p>
<p>Comments on this document should be sent to the W3C mailing
list <a href="mailto:public-qt-comments@w3.org">public-qt-comments@w3.org</a>
(archived at <a href="http://lists.w3.org/Archives/Public/public-qt-comments/">http://lists.w3.org/Archives/Public/public-qt-comments/</a>).</p>
<p>As of this publication, the Working Group expects to eventually
publish this document as a Working Group Note. It is not expected to
become a W3C Recommendation, and therefore it has no associated <a
href="http://www.w3.org/Consortium/Patent-Policy-20040205">W3C
Patent Policy licensing</a> obligations.</p>
<p>A list of current W3C Recommendations and other technical
documents can be found at <a href="http://www.w3.org/TR/">http://www.w3.org/TR/</a>.</p>
<h2><a name="contents" id="contents">Table of contents</a></h2>1
<a href="http://www.w3.org/TR/xpath20req#section-Goals">Goals</a><br />
2 <a href="http://www.w3.org/TR/xpath20req#section-Requirements">Requirements</a><br />
3 <a href="http://www.w3.org/TR/xpath20req#section-References">References</a><br />
<h3><a name="appendices" id="appendices"></a>Appendices</h3>
<hr />
<h2><a name="section-Goals" id="section-Goals"></a>1 Goals</h2>
<p>XPath 2.0 has the following goals:</p>
<ul>
<li>Simplify manipulation of XML Schema-typed content</li>
<li>Simplify manipulation of string content</li>
<li>Support related XML standards</li>
<li>Improve ease of use</li>
<li>Improve interoperability</li>
<li>Improve i18n support</li>
<li>Maintain backward compatibility</li>
<li>Enable improved processor efficiency</li>
</ul>
<h2><a name="section-Requirements" id="section-Requirements"></a>2 Requirements</h2>
<table summary="Presentation" border="0" cellspacing="0" width="100%">
<tbody>
<tr class="r1">
<td class="item" align="right" valign="top"><b>1</b></td>
<td colspan="3" class="item">
<span class="req-must">Must&nbsp;Support the XML "Family"
of Standards</span><br />
<p>As part of the evolving family of XML standards, XPath
2.0 MUST support the W3C XML architecture by integrating
well with other standards in the family.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.1</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Express Data model in
Terms of the Infoset</span><br />
<p>XPath 2.0 data model MUST be expressed in terms of the
<a href="#Infoset">XML Infoset</a>, including Post Schema
Validation Infoset contributions. Ideally, XSLT, XPath,
and XML Query should share a common data model.</p>
<p class="satisfied">Satisfied by the <a href="http://www.w3.org/TR/xpath-datamodel/#intro">Introduction</a>
section in <a href="#XQDM">[XQuery 1.0 and XPath 2.0 Data
Model]</a>.</p>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.2</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Provide Common Core
Syntax and Semantics for XSLT 2.0 and XML Query
1.0</span><br />
<p>XSLT 2.0 contains an expression language which is
"XPath 2.0 plus XSLT 2.0 extensions". XML Query 1.0
contains an expression language which we believe should
be "XPath 2.0 plus XML Query 1.0 extensions." The scope
of XPath 2.0 must be the set of common functionality
between the expression language of XSLT 2.0 and the
expression language of XML Query 1.0. This will guarantee
for Web developers and users that any common
functionality are implemented with identical syntax and
semantics.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-introduction">Introduction</a>
in <a href="#XPath2">[XPath 2.0]</a>.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.3</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Support Explicit "For
Any" or "For All" Comparison and Equality
Semantics</span><br />
<p>It MUST be possible for boolean expressions involving
node-sets to explicitly use "for any" or "for all"
semantics, otherwise known as explicit existential
quantification and explicit universal quantification,
respectively. Any <i>implicit</i> quantification should
be explained in terms of these explicit semantics.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath20/#id-quantified-expressions">Quantified Expressions</a> in <a href="#XPath2">[XPath 2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>The following examples illustrate limitations
of XPath 1.0 that can be addressed by the
addition of existential and universal quantifiers
to XPath 2.0:</p>
<ol>
<li>In XPath 1.0, the expression <code>5 &gt;
$ns</code> evaluates to true if <code>5</code>
is greater than the <code>number()</code> value
of at least one node in the <code>$ns</code>
node set. There is no way to test whether
<code>5</code> is greater than the
<code>number()</code> values of all nodes in
<code>$ns</code>.</li>
<li>In XPath 1.0, the expression <code>$ns1
&gt; $ns2</code> evaluates to true if the
<code>number()</code> value of at least one
node in <code>$ns1</code> is greater than the
<code>number()</code> value of at least one
node in the <code>$ns2</code> node set. There
is no way to test whether the
<code>number()</code> values of all of the
nodes in <code>$ns1</code> are greater than all
the <code>number()</code> values of all nodes
in <code>$ns2</code>.</li>
<li>In XPath 1.0, the expression <code>5 =
$ns</code> evaluates to true if <code>5</code>
equals the <code>number()</code> value of at
least one node in the <code>$ns</code> node
set. There is no way to test whether
<code>5</code> equals the <code>number()</code>
value of all nodes in <code>$ns</code>.</li>
<li>In XPath 1.0, the expression <code>$ns1 =
$ns2</code> evaluates to true if the
<code>number()</code> value of at least one
node in <code>$ns1</code> equals the
<code>number()</code> value of at least one
node in the <code>$ns2</code> node set. There
is no way to test whether the
<code>number()</code> values of all of the
nodes in <code>$ns1</code> are greater than all
the <code>number()</code> values of all nodes
in <code>$ns2</code>.</li>
<li>In XPath 1.0, the expression <code>0 +
LineItem/@UnitPrice &gt; 40</code> is
equivalent to <code>0 +
number(OrderDetail/@UnitPrice) &gt; 40</code>
which will be true if the <i>first</i>
<code>LineItem</code> element's
<code>UnitPrice</code> attribute is greater
than 40. However, the expression
<code>LineItem/@UnitPrice &gt; 40</code> is
true if <i>any</i> of the <code>LineItem</code>
elements' <code>UnitPrice</code> attributes is
greater than 40. This difference in behavior
could be resolved through explicit
quantification.</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.4</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Extend Set of
Aggregation Functions</span><br />
<p>XPath 1.0 currently supports <code>sum()</code> and
<code>count()</code>. XSLT users have frequently
requested the addition of <code>min()</code> and
<code>max()</code>. XPath 2.0 MUST address this by
extending its basic set of aggegration functions by
adopting some or all of the ones defined for XML
Query.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#aggregate.functions">Aggregate Functions</a> in <a href="#XPathFO">[XQuery 1.0 and XPath
2.0 Functions and Operators]</a>.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.5</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Maintain Backwards
Compatibility with XPath 1.0</span><br />
<p>Any valid XPath 1.0 expression SHOULD also be a valid
XPath 2.0 expression, and have the same semantics when
operating in the absence of XML Schema type information.
If not possible to achieve due to other requirements,
XPath 2.0 should minimize the number of changes to the
XPath 2.0 syntax to maximize backward compatibility with
XPath 1.0.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-backwards-compatibility">Backwards Compatibility with XPath 1.0</a> in <a href="#XPath2">[XPath 2.0]</a>.</p>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.6</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Provide Intersection
and Difference Functions</span><br />
<p>XPath 1.0 supports the union of two node sets. Set
functionality in XPath 2.0 SHOULD be expanded to include
intersection and difference functions, and should be
compatible with equivalent functions supported by XML
Query.</p>
<p class="satisfied">Satisfied by <em>union</em>,
<em>intersect</em>, and <em>except in</em> section
<a href="http://www.w3.org/TR/xpath20/#combining_seq">
Combining Node Sequences</a> in <a href="#XPath2">[XPath
2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>
<p>Given an XML document like:</p>
<div class="java-class">
&lt;hr&gt;<br />
&nbsp;&nbsp; &lt;teams&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;team
id="t1"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;members
ref="e101 e103"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;/team&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;team
id="t2"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;members
ref="e102"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;/team&gt;<br />
&nbsp;&nbsp;&lt;/teams&gt;<br />
&nbsp;&nbsp;&lt;departments&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;department&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;employee
id="e101" name="Steve"
teams="t1"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;employee
id="e102" name="Jonathan"
teams="t2"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;employee
id="e103" name="James"
teams="t1"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;/department&gt;<br />
&nbsp;&nbsp;&lt;/departments&gt;<br />
&lt;/hr&gt;
</div><br />
<p>Format the list of employees that work in
the same department as the
<code>employee</code> with <code>id</code> =
<code>e101</code> and that are on the same
teams as that employee. To accomplish
this:</p>
<ul>
<li>
<p>Select the list of all employees in
the employee's department:</p>
<div class="java-class">
id('e101')/parent::department/employee
</div><br />
</li>
<li>
<p>Intersect that set with the list of
all employees who are members of the
current employee's teams:</p>
<div class="java-class">
id('e101')/id(id(@teams)/members/@ref)
</div><br />
</li>
<li>
<p>Difference that set with the list
containing the current employee so they
don't appear in their own list of team
members:</p>
<div class="java-class">
id('e101')
</div><br />
</li>
</ul>
<p>The result should be the employee
"James".</p>
</li>
<li>
<p>Given an XML document full of book
information, a book with multiple authors
appears like this:</p>
<div class="java-class">
&lt;books&gt;<br />
&nbsp;&nbsp;&lt;book&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;title&gt;Exciting
New Book&lt;/title&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;author&gt;Kay&lt;/author&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;author&gt;Muench&lt;/author&gt;<br />
&nbsp;&nbsp;&lt;/book&gt;<br />
&nbsp;&nbsp;&lt;book&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;title&gt;Building
Oracle XML Applications&lt;/title&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;author&gt;Muench&lt;/author&gt;<br />
&nbsp;&nbsp;&lt;/book&gt;<br />
&nbsp;&nbsp;&lt;book&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;title&gt;XSLT
Programmer's Reference&lt;/title&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;author&gt;Kay&lt;/author&gt;<br />
&nbsp;&nbsp;&lt;/book&gt;<br />
&lt;/books&gt;
</div><br />
<p>Assuming an XSLT key is defined as
follows:</p>
<div class="java-class">
&lt;xsl:key name="auth" match="book"
use="author"/&gt;
</div><br />
<p>then, to find the list of books that have
both Muench and Kay among their authors, you
need to select the intersection of
<code>key('auth','Muench')</code> and
<code>key('auth','Kay')</code>.</p>
<p>To find books authored by Muench but
<i>not</i> by Kay, you need to select the
difference of
<code>key('auth','Muench')</code> and
<code>key('auth','Kay')</code>.</p>
</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>1.7</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Support Unary Plus
Operator</span><br />
<p>XML Schema allows decimals to have a leading plus. To
align better with this, XPath 2.0 SHOULD allow this by
providing a unary plus operator.</p>
<blockquote>
<p><b>Ed. Note:</b> There's a potential though rather
remote problem if there are nodes in the source
document containing a number with a leading plus sign.
Currently the defined behavior is to convert these
values to <code>NaN</code>, and this will change. A
stylesheet that is looking for phone-numbers beginning
with "+" might rely on this.</p>
</blockquote>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#func-numeric-unary-plus">op:numeric-unary-plus</a> in <a href="#XPathFO">[XQuery 1.0 and XPath 2.0 Functions and Operators]</a>.</p>
</td>
</tr>
<tr class="r1">
<td class="item" align="right" valign="top"><b>2</b></td>
<td colspan="3" class="item">
<span class="req-must">Must&nbsp;Improve Ease of
Use</span><br />
<p>Users of XPath 1.0 have requested enhancements to
simplify expression of common XPath use cases. XPath 2.0
MUST address these frequently requested enhancements.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>2.1</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Loosen Restrictions on
Location Steps</span><br />
<p>To better align with <a href="#XPointer">XPointer</a>
and to simplify the use of XPath expressions in which
multiple alternatives are allowed for a given location
step, XPath 2.0 MUST relax current restrictions for what
can appear after a '<code>/</code>' in an XPath
expression. Neither unions nor node-set functions are
allowed to appear after a '<code>/</code>' in XPath
1.0.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath20/#id-steps">Steps</a> which allow union and node-set functions in
<a href="#XPath2">[XPath 2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>
<p>An XPointer's expression can use node-set
functions on the right of the
'<code>/</code>' in a path:</p>
<div class="java-class">
id("chap1")/range-to(id("chap2"))
</div><br />
</li>
<li>
<p>Allowing unions in a location step would
allow expressions like:</p>
<div class="java-class">
/foo/(xxx|yyy)/li/(p|eg)
</div><br />
<p>instead of the more cumbersome:</p>
<div class="java-class">
/foo/xxx/li/p&nbsp;&nbsp;|<br />
/foo/xxx/li/eg |<br />
/foo/yyy/li/p&nbsp;&nbsp;|<br />
/foo/yyy/li/eg
</div><br />
</li>
<li>
<p>Allowing node-set functions to appear in a
location step would allow expressions
like:</p>
<div class="java-class">
document("otherdoc.xml")/id("foo")/a/b
</div><br />
<p>and</p>
<div class="java-class">
document("otherdoc.xml")/key("x","foo")/a/b
</div><br />
</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>2.2</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Provide a Conditional
Expression</span><br />
<p>Many users have requested the ability to return a
conditional value based on a boolean expression. XPath
2.0 MUST provide a conditional expression which takes
three expressions:</p>
<ol>
<li><i>expression1 (boolean)</i></li>
<li><i>expression2</i></li>
<li><i>expression3</i></li>
</ol>
<p>and evaluates to <i>expression2</i> if
<i>expression1</i> is <code>true</code> and to
<i>expression3</i> if <code>expression1</code> is
<code>false</code>. Only <i>expression1</i> and the
expression to be returned must be evaluated.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath20/#id-conditionals">Conditional Expressions</a> in <a href="#XPath2">[XPath
2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p><b>XSLT Use Cases</b></p>
<ol>
<li>In a template, construct a
<code>&lt;table&gt;</code> element with a
<code>border</code> attribute whose value is
provided by an <i>attribute value template</i>
and is conditional depending on the value of
the <code>frame</code> attribute of the current
node. If <code>@frame = 'none'</code>, then the
value of <code>border</code> should be
<code>0</code>, otherwise the value of
<code>border</code> should be
<code>1</code>.</li>
<li>Assign an XSLT variable a conditional value
based on whether the current node has any
<code>&lt;test&gt;</code> element children. If
it does, assign the value "<code>is</code>" to
the variable, otherwise assign the value
"<code>is not</code>".</li>
<li>
<p>Given a source XML document like this:</p>
<div class="java-class">
&lt;Emps&gt;<br />
&nbsp;&nbsp;&lt;Emp&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;
&lt;LastName&gt;Smith&lt;/LastName&gt;<br />
&nbsp;&nbsp;&lt;/Emp&gt;<br />
&nbsp;&nbsp;&lt;Emp&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;CommonName&gt;Scott&lt;/CommonName&gt;<br />
&nbsp;&nbsp;&lt;/Emp&gt;<br />
&lt;/Emps&gt;
</div><br />
<p>provide an <code>&lt;xsl:sort&gt;</code>
select expression to sort the list of
employees on the value of their
<code>&lt;LastName&gt;</code> if it's
present, otherwise on the value of their
<code>&lt;CommonName&gt;</code> element.</p>
</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>2.3</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Define Consistent
Implicit Semantics for Collection-Valued
Subexpressions</span><br />
<p>In XPath 1.0, the use of a collection-valued
subexpression can introduce an implicit existential
quantification or choose-first-member operation into the
containing expression's semantics. XPath 2.0 MUST define
a consistent implicit semantics for expressions that have
collection-valued subexpressions. This may require that
XPath 2.0 expressions use explicit quantification or
indexing expressions to achieve the same implicit
semantics provided in XPath 1.0.</p>
<p class="satisfied">Satisfied by inclusion of implicit
existential quantification in <a href="http://www.w3.org/TR/xpath20/#id-general-comparisons">General Comparisons</a> in <a href="#XPath2">[XPath
2.0]</a>. Note that it is not included in Value
Comparisons. The first member semantics were dropped
except for Backwards Compatibility mode.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>In XPath 1.0, the expression
<code>a[b=5]</code> returns
<code>&lt;a&gt;</code> elements that have ANY
<code>&lt;b&gt;</code> element child with value
5, where as the expression
<code>a[b+1=6]</code> returns
<code>&lt;a&gt;</code> elements whose FIRST
<code>&lt;b&gt;</code> element child has value
5. These results should be consistent for XPath
2.0.
<p class="satisfied">In 2.0 a[b+1=6] will
return an error if more than one b where in
1.0 it will ignore the other b's. This
produces a less surprising result for our
users.</p>
</li>
<li>Assume for this use case that the
typed-value of an element or attribute is
referenced using the syntax
<code>typed-value(elt)</code> and
<code>typed-value(@attr)</code>, respectively.
In XPath 2.0, when working with the typed value
of an element or attribute with
<code>boolean</code> type, the expression
<code>a[typed-value(b) = false()]</code> should
return <code>&lt;a&gt;</code> elements having
at least one <code>&lt;b&gt;</code> element
child with <code>boolean</code> value
<code>false</code>. Similarly, the expression
<code>a[typed-value(@b) = false()]</code>
should return &lt;a&gt; elements having a
boolean attribute <code>b</code> with value
<code>false</code>.</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>2.4</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Support Additional
String Functions</span><br />
<p>Users of XSLT 1.0 have requested additional string
manipulation functions. Common requests include string
padding (with spaces, dashes, or other characters),
string replacement, and converting strings to upper and
lower case. XPath 2.0 SHOULD provide additional string
functions. As with any string functions,
internationalization issues need to be addressed to
insure that the functionality is as broadly useful as
possible.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top">
<b>2.4.1</b></td>
<td class="item">
<span class="req-should">Should&nbsp;Simplify String
Replacement</span><br />
<p>XPath 1.0 provides the <code>translate()</code>
function that allows each single character in a source
string to be translated to another single character in
the result string, or to be removed. Users of XPath 1.0
frequently want to replace <i>sequences</i> of
consecutive characters with other sequences of
characters, which <code>translate()</code> does not
support. XPath 2.0 SHOULD support a more flexible string
replacement function.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#string.match">String Functions that Use Pattern Matching</a> in <a href="#XPathFO">[XQuery 1.0 and
XPath 2.0 Functions and Operators]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>Replace each occurrence of "<code>foo</code>"
in a string with "<code>foobar</code>".</p>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top">
<b>2.4.2</b></td>
<td class="item">
<span class="req-should">Should&nbsp;Simplify String
Padding</span><br />
<p>Often string values need to be padded on the left or
right to make the value occupy a fixed length. XPath 2.0
SHOULD support a string padding function that permits any
character as a padding character.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath-functions/#string-pad">eg:string-pad</a> in <a href="#XPathFO">[XQuery 1.0 and
XPath 2.0 Functions and Operators]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>Pad the value of a string on the right to
ensure a length of 10 characters using
spaces</li>
<li>Pad the value of a string on the left to 10
characters using asterisks</li>
<li>Output a string containing as many dashes
as the length of a section title</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top">
<b>2.4.3</b></td>
<td class="item">
<span class="req-should">Should&nbsp;Simplify String Case
Conversions</span><br />
<p>XPath 2.0 SHOULD provide the ability to convert the
case of text to upper or lower case for presentation
and/or comparison.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#func-upper-case">fn:upper-case</a> and <a href="http://www.w3.org/TR/xpath-functions/#func-lower-case">fn:lower-case</a> in <a href="#XPathFO">[XQuery 1.0 and
XPath 2.0 Functions and Operators]</a>.</p>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>2.5</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Support Aggregation
Functions Over Collection-Valued Expressions</span><br />
<p>Users of XPath 1.0 frequently request the ability to
apply an aggregate function, like <code>sum()</code>, to
the values of expressions applied to a node set. XPath
2.0 SHOULD support aggregation functions over expressions
applied to node sets.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-for-expressions">For
Expressions</a> in <a href="#XPath2">[XPath2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>
<p>Given a document like</p>
<div class="java-class">
&lt;sect title="Plan"&gt;<br />
&nbsp;&nbsp; &lt;sect
title="Overview"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;sect
title="Competitors"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;sect
title="SuperSoft"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;sect
title="BarnWare"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;/sect&gt;<br />
&nbsp;&nbsp; &lt;/sect&gt;<br />
&nbsp;&nbsp; &lt;sect
title="Details"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;sect
title="Summary"/&gt;<br />
&nbsp;&nbsp; &lt;/sect&gt;<br />
&lt;/sect&gt;
</div><br />
<p>Calculate the maximum depth of the nesting
of <code>&lt;sect&gt;</code> elements. The
nodeset is identified by the expression
<code>//sect</code> and the expression to
maximize would be
<code>count(ancestor-or-self::sect)</code>.</p>
</li>
<li>Given the same document above, calculate
the average string length of section titles.
The nodeset is identified by
<code>//section/@title</code> and the
expression to sum would be
<code>string-length(.)</code>, divided by the
<code>count(//section/@title)</code></li>
<li>Given an XML document containing a purchase
order and its line <code>&lt;item&gt;</code>
elements, calculate the total amount of the
purchase order by summing the price times the
quantity of each item. The nodeset is
identified by <code>item</code>, and the
expression to sum would be <code>price *
quantity</code>.</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" align="right" valign="top"><b>3</b></td>
<td colspan="3" class="item">
<span class="req-must">Must&nbsp;Support String Matching
Using Regular Expressions</span><br />
<p>Regular expressions provide a powerful way to specify
string pattern matching and now play an important role in
XML Schema as the mechanism by which pattern facets are
specified. XPath 2.0 MUST support regular expressions for
matching against strings using the regular expression
notation established in <a href="#XSchemaData">XML
Schema: Datatypes</a>.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#regex-syntax">Regular Expression Syntax</a> in <a href="#XPathFO">[XQuery 1.0 and XPath 2.0 Functions and
Operators]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>
<p>Given XML like:</p>
<div class="java-class">
&lt;Data&gt;<br />
&nbsp;&nbsp;&lt;EmpRow&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp; :<br />
&nbsp;&nbsp;&lt;/EmpRow&gt;<br />
&nbsp;&nbsp;&lt;DeptRow&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;
&lt;Deptno&gt;10&lt;/Deptno&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;
&lt;Employees&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;EmpRow&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Empno&gt;1000&lt;/Empno&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;Ename&gt;1000&lt;/Ename&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;/Emprow&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;
&lt;/Employees&gt;<br />
&nbsp;&nbsp;&lt;/DeptRow&gt;<br />
&lt;/Data&gt;
</div><br />
<p>match elements that "end with
<code>Row</code> or <code>row</code>"</p>
<div class="java-class">
*[local-name() =~ ".*[rR]ow"]
</div><br />
</li>
<li>
<p>Match phone numbers like 123-456-7890</p>
<div class="java-class">
field[ . =~ "\d\d\d-\d\d\d\-\d\d\d\d"]
</div><br />
</li>
<li>
<p>Match any element name with the string
"Addr" contained within the name
(case-insensitively)</p>
<div class="java-class">
*[local-name() =~ ".*[Aa][Dd][Dd][Rr].*"]
</div><br />
</li>
<li>
<p>Match a string from a dynamic regular
expression</p>
<div class="java-class">
Department[Code =~
concat("[0-9][0-9]",$v,".*")]
</div><br />
</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" align="right" valign="top"><b>4</b></td>
<td colspan="3" class="item">
<span class="req-must">Must&nbsp;Add Support for XML
Schema Primitive Datatypes</span><br />
<p><a href="#XSchemaData">[XML Schema: Datatypes]</a>
defines a set of primitive datatypes. In addition to the
types supported by the XPath 1.0 data model,
<code>string</code>, <code>number</code>,
<code>boolean</code>, and <code>node-set</code>, the
XPath 2.0 data model MUST support XML Schema primitive
types. XPath 2.0 will extend the XPath data model to
accommodate working with elements and attribute values
having an XML Schema primitive type.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.1</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Define the Operator
Matrix and Conversions</span><br />
<p>XPath 2.0 MUST support the operators and type-coercion
rules defined by the joint XSLT/Schema/Query task force
on operators.</p>
<p class="satisfied">Satisfied by sections</p>
<ul class="satisfied">
<li><a href="http://www.w3.org/TR/xpath-functions/#numeric-functions">Functions and Operators on Numerics</a></li>
<li><a href="http://www.w3.org/TR/xpath-functions/#d1e3606">Functions and Operators on Boolean Values</a></li>
<li><a href="http://www.w3.org/TR/xpath-functions/#durations-dates-times">Functions and Operators on Durations, Dates and
Times</a></li>
<li><a href="http://www.w3.org/TR/xpath-functions/#QName-funcs">Functions Related to QNames</a></li>
</ul>
<p class="satisfied">in <a href="#XPathFO">[XQuery 1.0
and XPath 2.0 Functions and Operators]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ul>
<li>
<p><b>General</b></p>
<ol>
<li>Use and create the type information of
any datatype</li>
<li>Do not require the user to respecify
the datatype (i.e. number and boolean)</li>
<li>Maintain the facet constraints of
primitive datatypes while manipulating the
value. For example, take a 14.4 number plus
a 14.4 number and return a 14.4
number.</li>
</ol>
</li>
<li>
<p><b>For DateTime</b></p>
<ol>
<li>Compare dates of documents and return a
boolean</li>
<li>Add a time or date interval and return
the same type</li>
<li>Add a scalar value to a time or date
and return the same type</li>
<li>
<p>Calculate an end time from a start
time+duration. For example, given:</p>
<div class="java-class">
&lt;appointment
time="20001224-16:00:00"
duration="1:00"/&gt;
</div>
<p>Produce the end-time:</p>
<div class="java-class">
End time: &lt;xsl:value-of
select="@time + @duration"/&gt;
</div><br />
</li>
<li>
<p>Detect intersections between datetime
durations</p>
<div class="java-class">
&lt;appointment
time="20001224-16:00:00"
duration="2:00" reminder="0:15"/&gt;
</div><br />
<div class="java-class">
&lt;appointment
time="20001224-17:00:00"
duration="1:00" reminder="0:15"/&gt;
</div><br />
</li>
</ol>
</li>
<li>
<p><b>For Boolean</b></p>
<p>Perform pattern matching on "yes" and
"no"</p>
</li>
<li>
<p><b>For QName</b></p>
<ol>
<li>Build a Namespace element from a
QName</li>
<li>Compare a Namespace URI from a QName
with a string</li>
</ol>
</li>
</ul>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.2</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Allow Scientific
Notation for Numbers</span><br />
<p>XML Schema specifies a lexical representation for
doubles and floats that includes scientific notation as
well as <code>INF</code>, <code>-INF</code> or
<code>NaN</code>. XPath 2.0 MUST support the lexical
representations of floats and doubles supported by XML
Schema.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#d1e1156">Numeric Types</a> in <a href="#XPathFO">[XQuery 1.0 and XPath 2.0 Functions and
Operators]</a>.</p>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.3</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Define Appropriate Cast
and Constructor Functions</span><br />
<p>XPath 2.0 MUST define an appropriate set of functions
to allow users to cast and construct instances of XML
Schema primitive types. At a minimum, this set MUST
include cast and constructor functions for URI and
date/time types.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-functions/#constructor-functions">Constructor Functions</a> and <a href="http://www.w3.org/TR/xpath-functions/#casting">Casting</a> in <a href="#XPathFO">[XQuery 1.0 and XPath
2.0 Functions and Operators]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>Be able to compare an element or attribute
with an XML Schema date or time type with a
constant date or time value.</p>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.4</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Add List Data Type
to the Type System of the Expression
Langauge</span><br />
<p>XML Schema allows the definition of simple types
derived by list, including lists of unions of non-list
simple types. XPath 2.0 SHOULD support an ordered list of
simple-typed values.</p>
<p class="satisfied">Satisfied by section <a href="http://www.w3.org/TR/xpath-datamodel/#sequences">Sequences</a> in <a href="#XQDM">[XQuery 1.0 and
XPath 2.0 Data Model]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>Create an XSLT transformation that converts an
element structure like this:</p>
<div class="java-class">
&lt;xdr:attribute name="a1"
dt:type="enumeration" dt:values="a1 a2 a3"/&gt;
</div><br />
<p>into an alternative structure like this:</p>
<div class="java-class">
&lt;xsd:attribute name="a1"&gt;<br />
&nbsp;&nbsp;&lt;xsd:simpleType&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;xsd:restriction
base="NMTOKEN"&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;xsd:enumeration
value="a1"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;xsd:enumeration
value="a2"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&lt;xsd:enumeration
value="a3"/&gt;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&lt;/xsd:restriction&gt;<br />
&nbsp;&nbsp;&lt;/xsd:simpleType&gt;<br />
&lt;/xsd:attribute&gt;
</div><br />
<p>This requires the ability in XPath to select
the list of NMTOKENS values of the
<code>dt:values</code> attribute for
processing.</p>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.5</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Support Accessing
Simple-Typed Value of Elements and
Attributes</span><br />
<p>The XPath 1.0 type system supports the
<code>number</code>, <code>string</code>,
<code>boolean</code>, and <code>node-set</code> types.
<a href="#XSchemaData">XML Schema: Datatypes</a>
introduces many new types. XPath 1.0 supports conversion
of the simple-typed values of elements and attributes to
strings. In addition to this functionality, XPath 2.0
MUST support access to the native, simple-typed value of
an element or attribute.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-typed-value">Typed Value and String Value</a>
in <a href="#XPath2">[XPath 2.0]</a>.</p>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>4.6</b></td>
<td colspan="2" class="item">
<span class="req-must">Must&nbsp;Define Behavior of
Operators for Null Arguments</span><br />
<p>Since the typed value of an element can be
<code>null</code>, XPath 2.0 MUST define how the behavior
of operations applies to null values.</p>
<p class="satisfied">Satisfied by the Empty Sequence
supported through the <a href="#XPath2">[XPath
2.0]</a> language.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>Assuming the typed value of an element is
addressed using a syntax like
<code>typed-value(elementname)</code>, XPath
needs to specify what <code>1.20 *
typed-value(salary)</code> evaluates to when the
typed value of the <code>&lt;salary&gt;</code> is
<code>null</code>.</p>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" align="right" valign="top"><b>5</b></td>
<td colspan="3" class="item">
<span class="req-should">Should&nbsp;Add Support for XML
Schema: Structures</span><br />
<p><a href="#XSchemaStruc">XML Schema: Structures</a>
enables users to define structured types and associate
them to elements in a schema. XPath 2.0 SHOULD provide
support for the common operations needed for navigation
and selection of typed elements.</p>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>5.1</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Select
Elements/Attributes Based on an Explicit XML Schema
Type</span><br />
<p>XML Schema : Structures provides the ability to define
the type of an element or attribute. XPath 2.0 SHOULD be
able to test whether an element or attribute is an
instance of a given type.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-sequencetype-matching">SequenceType
Matching</a> in <a href="#XPath2">[XPath 2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<ol>
<li>Select all elements that are instances of
the complex type <code>Address</code>.</li>
<li>Select all attributes that are instances of
the simple-type <code>xsd:integer</code>.</li>
<li>Select elements of type
<code>Address</code> indicated in the instance
with <code>xsi:type="Address"</code></li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>5.2</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Select
Elements/Attributes Based on XML Schema Type
Hierarchy</span><br />
<p>XML Schema : Structures provides the ability to define
a hierarchy of types by derivation. XPath 2.0 SHOULD be
able to selects elements or attributes that are instances
of a type, also matching any types derived from it by
restriction or extension.</p>
<blockquote>
<p><b>Ed. Note:</b> This introduces some interesting
precedence decisions about how matches for an explicit
type would need to take precedence over matches for
compatible types. In other words, given a template
matching elements with types compatible to
<code>Address</code> and another template explicitly
matching type <code>USAddress</code>, one would expect
the explicit type match to take precedence. Also
consider the case where two templates exist, one that
matches the <code>Address</code> type and one that
matches the <code>USAddress</code> type. If an element
of type RuralRouteAddress (further derived from
USAddress) is considered for matching, one would expect
the template for the "closest inherited ancestor", that
is <code>USAddress</code>, to take precendence over a
template matching the type of a "more distant inherited
ancestor" like <code>Address</code>.</p>
</blockquote>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-sequencetype-matching">SequenceType
Matching</a> in <a href="#XPath2">[XPath 2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p><b>Derivation by Restriction</b></p>
<p>The <a href="#XSchemaPri">[XML Schema:
Primer]</a> defines the <code>Items</code> type
and the <code>ConfirmedItems</code> type which is
derived by restriction from <code>Items</code>.
Select purchase orders whose
<code>&lt;items&gt;</code> member element is an
instance of the <code>ConfirmedItems</code> type,
which restricts the minimum number of
<code>&lt;item&gt;</code> elements that can
appear to be at least one.</p>
<p><b>Derivation by Extension</b></p>
<p>The <a href="#XSchemaPri">[XML Schema:
Primer]</a> defines the <code>Address</code> type
and the <code>UKAddress</code> and
<code>USAddress</code> types which is derived by
extension from <code>Address</code>, adding
additional element content in the subtypes.</p>
<ol>
<li>Select all elements that are instances of
complex type <code>Address</code>, matching
elements of type <code>USAddress</code> and
elements of type <code>UKAddress</code> as
well.</li>
<li>Select all elements that are instances of
complex type <code>Address</code>, without
selecting elements of types derived from
<code>Address</code>.</li>
<li>Select all attributes that are instances of
the simple-type <code>xsd:integer</code>,
matching attribute of type
<code>SKU-Number</code> which derives from
<code>xsd:integer</code>.</li>
</ol>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r1">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>5.3</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Select Elements
Based on XML Schema Substitution Groups</span><br />
<p><a href="#XSchemaData">[XML Schema: Datatypes]</a>
provides the ability to include two or more element names
in a substitution group. XPath 2.0 SHOULD be able to test
whether an element is a member of an XML Schema
substitution group.</p>
<p class="satisfied">Satisfied by <a href="http://www.w3.org/TR/xpath20/#id-sequencetype-matching">SequenceType
Matching</a> in <a href="#XPath2">[XPath 2.0]</a>.</p>
<table summary="Presentation" border="0">
<tbody>
<tr>
<td><span class="title"><b>Use Case</b></span></td>
</tr>
<tr>
<td>
<p>The <a href="#XSchemaPri">[XML Schema:
Primer]</a> defines the global
<code>&lt;ipo:comment&gt;</code> element as the
head of a substitution group, whose substitutible
member elements include
<code>&lt;ipo:customerComment&gt;</code> and
<code>&lt;ipo:shipComment&gt;</code>. Select the
list of all elements that are
<code>&lt;ipo:comment&gt;</code> elements,
including any elements that are substitutible for
<code>&lt;ipo:comment&gt;</code> through this
substitution group.</p>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr class="r0">
<td class="item" valign="top">
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td>
<td class="item" align="right" valign="top"><b>5.4</b></td>
<td colspan="2" class="item">
<span class="req-should">Should&nbsp;Support Lookups
Based on Schema Unique Constraints and Keys</span><br />
<p><a href="#XSchemaData">[XML Schema: Datatypes]</a>
supports named, multi-part keys. XPath 2.0 SHOULD support
a mechanism for looking up the element to which a Schema
key refers. Similar mechanisms already exist, such as the
<code>id()</code> function in XPath 1.0 and the
<code>key()</code> function in XSLT.</p>
<p class="notsatisfied">Not Satisfied due to lack of use
cases and existing functionality in host languages to
create keys.</p>
</td>
</tr>
</tbody>
</table>
<div class="div2">
<h2><a name="section-References" id="section-References"></a>3
References</h2>
<dl>
<dt class="label"><a id="XQDM" name="XQDM"></a>XQuery 1.0 and
XPath 2.0 Data Model</dt>
<dd>World-Wide Web Consortium <em>XQuery 1.0 and XPath 2.0
Data Model</em>. See <a href="http://www.w3.org/TR/xpath-datamodel/">http://www.w3.org/TR/xpath-datamodel/</a></dd>
<dt class="label"><a id="XPath" name="XPath"></a>XPath
1.0</dt>
<dd>World-Wide Web Consortium <em>XML Path Language
(XPath)</em>: Version 1.0. November, 1999. See <a href="http://www.w3.org/TR/xpath">http://www.w3.org/TR/xpath</a>.</dd>
<dt class="label"><a id="XPathReq" name="XPathReq"></a>XPath
Requirements Version 2.0</dt>
<dd>World Wide Web Consortium, <em>XPath Requirements Version
2.0</em>. See <a href="http://www.w3.org/TR/xpath20req">http://www.w3.org/TR/xpath20req</a>.</dd>
<dt class="label"><a id="XPath2" name="XPath2"></a>XPath
2.0</dt>
<dd>World-Wide Web Consortium <em>XML Path Language
(XPath)</em>: Version 2.0. See <a href="http://www.w3.org/TR/xpath20/">http://www.w3.org/TR/xpath20/</a>.</dd>
<dt class="label"><a id="XSLT2" name="XSLT2"></a>XSLT
2.0</dt>
<dd>World Wide Web Consortium, <em>XSL Transformations
Language (XSLT)</em>: Version 2.0. See <a href="http://www.w3.org/TR/xslt20/">http://www.w3.org/TR/xslt20/</a>.</dd>
<dt class="label"><a id="XQWG" name="XQWG"></a>XML Query
Working Group</dt>
<dd>World Wide Web Consortium, <em>XML Query Working
Group</em>. Home page: <a href="http://www.w3.org/XML/Query">http://www.w3.org/XML/Query</a>.</dd>
<dt class="label"><a id="XSLWG" name="XSLWG"></a>XSL Working
Group</dt>
<dd>World Wide Web Consortium, <em>XSL Working Group</em>.
Home page: <a href="http://www.w3.org/Style/XSL/">http://www.w3.org/Style/XSL/</a>.</dd>
<dt class="label"><a id="XQuery" name="XQuery"></a>XQuery
1.0: A Query Language for XML</dt>
<dd>World Wide Web Consortium, <em>XQuery 1.0: A Query
Language for XML</em>. See <a href="http://www.w3.org/TR/xquery/">http://www.w3.org/TR/xquery/</a>.</dd>
<dt class="label"><a id="XQueryReq" name="XQueryReq"></a>XML
Query Requirements</dt>
<dd>World Wide Web Consortium, <em>XML Query
Requirements</em>. See <a href="http://www.w3.org/TR/2005/WD-xquery-requirements-20050603/">http://www.w3.org/TR/2005/WD-xquery-requirements-20050603/</a>.</dd>
<dt class="label"><a id="XPointer" name="XPointer"></a>XPointer</dt>
<dd>World Wide Web Consortium, <em>XPointer xpointer()
Scheme</em>. See <a href="http://www.w3.org/TR/xptr-xpointer/">http://www.w3.org/TR/xptr-xpointer/</a>.</dd>
<dt class="label"><a id="XSchemaPri" name="XSchemaPri"></a>XML Schema: Primer</dt>
<dd>World Wide Web Consortium, <em>XML Schema Part 0:
Primer</em>. See <a href="http://www.w3.org/TR/xmlschema-0/">http://www.w3.org/TR/xmlschema-0/</a>.</dd>
<dt class="label"><a id="XSchemaStruc" name="XSchemaStruc"></a>XML Schema: Structures</dt>
<dd>World Wide Web Consortium, <em>XML Schema Part 1:
Structures</em>. See <a href="http://www.w3.org/TR/xmlschema-1/">http://www.w3.org/TR/xmlschema-1/</a>.</dd>
<dt class="label"><a id="XSchemaData" name="XSchemaData"></a>XML Schema: Datatypes</dt>
<dd>World Wide Web Consortium, <em>XML Schema Part 2:
Datatypes</em>. See <a href="http://www.w3.org/TR/xmlschema-2/">http://www.w3.org/TR/xmlschema-2/</a>.</dd>
<dt><a id="Infoset" name="Infoset"></a>XML Information
Set</dt>
<dd>World Wide Web Consortium, <em>XML Information Set</em>.
See <a href="http://www.w3.org/TR/xml-infoset/">http://www.w3.org/TR/xml-infoset/</a>.</dd>
<dt><a id="XPathFO" name="XPathFO"></a>XQuery 1.0 and XSLT
2.0 Functions and Operators</dt>
<dd>World Wide Web Consortium, <em>XQuery 1.0 and XSLT 2.0
Functions and Operators</em>. See <a href="http://www.w3.org/TR/xpath-functions/">http://www.w3.org/TR/xpath-functions/</a>.</dd>
<dt>&nbsp;</dt>
<dt>&nbsp;</dt>
<dt><a href="http://www.w3.org/TR/xptr-xpointer/"></a></dt>
</dl>
</div>
</body></html>