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<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"/>An XSD datatype for IEEE floating-point decimal</h1>
<h2><a name="w3c-doctype" id="w3c-doctype"/>W3C Working Group Note 9 June 2011</h2>
<dl>
<dt>This version:</dt>
<dd><a href="http://www.w3.org/TR/2011/NOTE-xsd-precisionDecimal-20110609/">http://www.w3.org/TR/2011/NOTE-xsd-precisionDecimal-20110609/</a></dd>
<dt>Latest version:</dt>
<dd><a href="http://www.w3.org/TR/xsd-precisionDecimal/">http://www.w3.org/TR/xsd-precisionDecimal/</a></dd>
<dt>Editors:</dt>
<dd>David Peterson, invited expert (SGML<em>Works!</em>) <a href="mailto:davep@iit.edu">&lt;davep@iit.edu&gt;</a></dd>
<dd>C. M. Sperberg-McQueen, Black Mesa Technologies LLC <a href="mailto:cmsmcq@blackmesatech.com">&lt;cmsmcq@blackmesatech.com&gt;</a></dd>
</dl>
<p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2011 <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.eu/"><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"/>Abstract</h2><p>
This document defines a datatype designed for
compatibility with IEEE 754 floating-point decimal
data, which can be supported by XSD 1.1 processors
as an <a href="http://www.w3.org/TR/xmlschema11-2/#key-impl-def">implementation-defined</a> datatype.
</p></div><div class="sotd">
<h2><a name="status" id="status"/>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 W3C
<a href="http://www.w3.org/2005/10/Process-20051014/tr.html#maturity-levels">Working Group Note</a> as described in the
<a href="http://www.w3.org/2005/10/Process-20051014/cover.html">World Wide Web Consortium Process Document</a>.
It contains a definition of a precisionDecimal datatype
designed for compatibility with IEEE 754
floating-point decimal numbers.
</p>
<p>In its current state, this document contains all the material
specific to the <a href="#precisionDecimal">precisionDecimal</a> datatype
that has appeared in working
drafts of <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>, including some
revisions made since the most recent public working draft.
It is substantially complete as a specification of the datatype,
though some further changes (listed in <a href="#to-do">To-do list (non-normative) (§D)</a>)
may be made in a future revision of this document.</p>
<p>
Comments on this document should be sent to the W3C XML Schema
comments mailing list, <a
href="mailto:www-xml-schema-comments@w3.org"
>www-xml-schema-comments@w3.org</a> (<a
href="http://lists.w3.org/Archives/Public/www-xml-schema-comments/"
>archive</a>). Each email message should contain only one
comment.
</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>
<p>
This document has been produced by the
<a href="http://www.w3.org/XML/Schema">W3C XML Schema Working Group</a>
as part of the W3C <a href="http://www.w3.org/XML/Activity">XML
Activity</a>. The authors of this document are
the members of the XML Schema Working Group.
</p>
<p>This document was produced by a group operating under the
<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5
February 2004 W3C Patent Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/19482/status">public list of any patent disclosures</a> made in
connection with the deliverables of the group; that page also
includes instructions for disclosing a patent. An individual
who has actual knowledge of a patent which the individual
believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the information in
accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the W3C Patent Policy</a>. </p>
</div><div class="toc">
<h2><a name="contents" id="contents"/>Table of Contents</h2><div class="toc">1 <a href="#intro">Introduction</a><br/>
2 <a href="#terminology">Definitions</a><br/>
3 <a href="#precisionDecimal">The precisionDecimal datatype</a><br/>
    3.1 <a href="#sec-vs-pD">Value Space</a>
<br/>
    3.2 <a href="#pD-lexical-mapping">Lexical Mapping</a>
<br/>
    3.3 <a href="#sec-f-pD">Facets</a>
<br/>
4 <a href="#facets">Facets for constraining precisionDecimal values</a><br/>
    4.1 <a href="#rf-totalDigits">totalDigits</a>
<div style="margin-left: 4em; margin-top: 0; margin-bottom: 0;">
<a href="#totalDigits-validation-rules">totalDigits Validation Rules</a></div>
    4.2 <a href="#rf-maxScale">maxScale</a>
<div style="margin-left: 4em; margin-top: 0; margin-bottom: 0;">
<a href="#dc-maxScale">The maxScale Schema Component</a> · <a href="#xr-maxScale">XML Representation of maxScale Schema Components</a> · <a href="#maxScale-validation-rules">maxScale Validation Rules</a> · <a href="#maxScale-coss">Constraints on maxScale Schema Components</a></div>
    4.3 <a href="#rf-minScale">minScale</a>
<div style="margin-left: 4em; margin-top: 0; margin-bottom: 0;">
<a href="#dc-minScale">The minScale Schema Component</a> · <a href="#xr-minScale">XML Representation of minScale Schema Components</a> · <a href="#minScale-validation-rules">minScale Validation Rules</a> · <a href="#minScale-coss">Constraints on minScale Schema Components</a></div>
5 <a href="#implementation-notes">Implementation issues</a><br/>
    5.1 <a href="#implementation-limits">Implementation limits</a>
<br/>
    5.2 <a href="#implementing-operators">Interfacing with XPath</a>
<br/>
6 <a href="#mappings">Mapping functions</a><br/>
</div>
<h3><a name="appendices" id="appendices"/>Appendices</h3><p class="toc">A <a href="#normative-refs">Normative references</a><br/>
B <a href="#non-normative-refs">Non-normative references</a><br/>
C <a href="#acknowledgments">Acknowledgements (non-normative)</a><br/>
D <a href="#to-do">To-do list (non-normative)</a><br/>
</p></div><hr/><div class="body"><div class="div1">
<h2><a name="intro" id="intro"/>1 Introduction</h2><p>This document defines an XSD datatype intended to support the
floating-point decimal defined by IEEE 754.
</p><p>
IEEE 754 defines both floating-point binary and floating-point decimal
formats. The binary formats have been widely adopted since their
initial introduction; if the floating-point decimal formats are also
widely adopted for applications, it will be convenient to be able to
represent values of that type in XML documents or in other contexts
where XSD datatypes are used.
</p></div><div class="div1">
<h2><a name="terminology" id="terminology"/>2 Definitions</h2><p>The following terms are used in this specification with
the meanings indicated.</p><p>Except as specified below, in this specification terms
defined in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a> have the meanings given
there.</p><div class="glist"><div class="gitem"><div class="giLabel">
<span class="termdef"><a name="dt-constraining-facet" id="dt-constraining-facet" title="">[Definition:]  </a>
<b>constraining facet</b>
</span>
</div><div class="giDef"><div class="p">A schema component whose value may be set or changed
during <a href="http://www.w3.org/TR/xmlschema11-2/#dt-derived">derivation</a>
(subject to facet-specific constraints) to control various
aspects of a derived datatype.
</div></div></div><div class="gitem"><div class="giLabel">
<span class="termdef"><a name="dt-fundamental-facet" id="dt-fundamental-facet" title="">[Definition:]  </a>
<b>fundamental facet</b>
</span>
</div><div class="giDef"><div class="p">
A schema component that provides a limited piece of
information about some aspect of a datatype.
</div></div></div><div class="gitem"><div class="giLabel">
<span class="termdef"><a name="dt-specialvalue" id="dt-specialvalue" title="">[Definition:]  </a><b>special value</b>
</span>
</div><div class="giDef"><div class="p">One of the possible values of the
<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> property of
<a href="#precisionDecimal">precisionDecimal</a> values, whose only relevent property,
for purposes of this document and of
<a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>, lie in its
being distinct from the other possible values;
specifically, <b><i>positiveInfinity</i></b>,
<b><i>negativeInfinity</i></b>, and
<b><i>notANumber</i></b>.</div><div class="p">Informally, any <a href="#precisionDecimal">precisionDecimal</a> value whose
<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> property is
such a special value.</div><div class="note"><div class="p"><b>Note:</b> The names of these special values are shared with the
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-specialvalue">special
values</a> of the float and double datatypes.</div></div></div></div></div></div><div class="div1">
<h2><a name="precisionDecimal" id="precisionDecimal"/>3 The precisionDecimal datatype</h2><p><span class="termdef"><a name="dt-precisionDecimal" id="dt-precisionDecimal" title="">[Definition:]  </a>The
<b>precisionDecimal</b> datatype represents decimal numbers which retain precision; it also
includes values for positive and negative infinity and for
"not a number", and it differentiates between
"positive zero" and "negative
zero".</span>  This datatype is introduced to
provide a variant of decimal from
which may be derived datatypes closely corresponding to
the floating-point decimal datatypes described by <a href="#ieee754-2008">[IEEE 754-2008]</a>.  </p><div class="note"><div class="p"><b>Note:</b> The <a href="#precisionDecimal">precisionDecimal</a> datatype also permits derivation of a datatype
closely corresponding to Java BigDecimal, although
implementation is permitted to be confined to a much smaller
value space.</div></div><div class="note"><div class="p"><b>Note:</b> Users wishing to implement useful operations for this
datatype (beyond the equality and order specified herein) are
urged to consult <a href="#ieee754-2008">[IEEE 754-2008]</a>.</div></div><p> The
datatype <a href="#precisionDecimal">precisionDecimal</a> draws its name from a
common usage of the term 'precision' to mean the
degree of accuracy with which a quantity is recorded. In this
usage, writing a number as '<code>2</code>' or as
'<code>2.00</code>' is taken as recording the value with less or
more precision.</p><div class="note"><div class="p"><b>Note:</b> See the <a href="http://www.w3.org/TR/xmlschema11-2/#partial-implementation">conformance note</a>
in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>, which applies to this
datatype.</div></div><div class="div2">
<h3><span class="nav"> <a href="#pD-lexical-mapping" class="nav"><img alt="next sub-section" src="next.jpg"/></a></span><a name="sec-vs-pD" id="sec-vs-pD"/>3.1 Value Space</h3><div class="defset">
<div class="defset-head">Properties of
<a href="#precisionDecimal">precisionDecimal</a> Values</div>
<div class="deftop">
<b><a name="vp-pd-numVal" id="vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a></b></div>
<div class="defindent">a decimal number, <b><i>positiveInfinity</i></b>,
<b><i>negativeInfinity</i></b> or <b><i>notANumber</i></b></div>
<div class="deftop">
<b><a name="vp-pd-precision" id="vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a></b></div>
<div class="defindent">an integer or <b><i>absent</i></b>;
<b><i>absent</i></b> if and only if <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is a
special value.</div>
<div class="deftop">
<b><a name="vp-pd-sign" id="vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a></b></div>
<div class="defindent"><b><i>positive</i></b>, <b><i>negative</i></b>, or
<b><i>absent</i></b>; <span class="rfc2119">must</span> be <b><i>positive</i></b> if <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is positive or <b><i>positiveInfinity</i></b>,
<span class="rfc2119">must</span> be <b><i>negative</i></b> if <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is
negative or <b><i>negativeInfinity</i></b>, <span class="rfc2119">must</span> be <b><i>absent</i></b>
if and only if <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is
<b><i>notANumber</i></b></div>
</div>
<div class="note"><div class="p"><b>Note:</b> The <a href="#vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a> property is redundant except
when <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is zero; in other cases, the
<a href="#vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a> value is fully determined by the
<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> value.</div></div><div class="note"><div class="p"><b>Note:</b> As explained below, '<code>NaN</code>' is the lexical
representation of the <a href="#precisionDecimal">precisionDecimal</a> value whose <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> property has the special value
<b><i>notANumber</i></b>.  Accordingly, in English text we
use 'NaN' to refer to that value. 
Similarly we use 'INF' and
'−INF' to refer to the two values
whose <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> properties have the
special values <b><i>positiveInfinity</i></b> and
<b><i>negativeInfinity</i></b>.  These three <a href="#precisionDecimal">precisionDecimal</a> values
are also informally called "not-a-number",
"positive infinity", and "negative
infinity". The latter two together are called
"the infinities".</div></div><div class="note"><div class="p"><b>Note:</b> The datatype defined here is intended to allow the
derivation of less general datatypes corresponding to the
decimal formats defined by <a href="#ieee754-2008">[IEEE 754-2008]</a>. Those formats can be viewed as
representing values other than the infinities and NaN as
triples (<var>s</var>, <var>q</var>, <var>m</var>), where
<var>s</var> is the <em>sign</em> bit,
<var>q</var> is the <em>exponent</em> (an integer), and
<var>m</var> is the <em>significand</em> (also an
integer).
(The "<var>q</var>" form of IEEE's
<em>exponent</em> is used when treating the
<em>significand</em> as an integer.) The <a href="#precisionDecimal">precisionDecimal</a> <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> is (–1 ^ <var>s</var>) × (10 ^ <var>q</var>) ×
<var>m</var> and the <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> is <var>q</var>.
Conversely, for nonzero finite values the <em>sign</em>
<var>s</var> is the <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> divided by its
absolute value, the integer <em>significand</em> <var>m</var> is
|<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a>| / (10 ^ <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>), and, of course, the exponent <var>q</var> is
the <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>.</div><div class="p">
The single NaN of <a href="#precisionDecimal">precisionDecimal</a> corresponds both to the signaling
NaN and to the quiet NaN of [IEEE 754-2008], which permits
the use of a single NaN when values are being transmitted
from one system to another via <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a>.
</div><div class="p">
The individual decimal formats defined by <a href="#ieee754-2008">[IEEE 754-2008]</a> are
characterized by the range of values allowed for the
<em>exponent</em> and by the number of decimal digits
available for the <em>significand</em>, which IEEE
terms the <em>precision</em> of the format. In any
given IEEE 754 decimal format there may be multiple
representations representing the same numerical value, one
with its significand using the maximum number of
significant digits available in the format, and the others
with fewer significant digits (when that is possible). Note
that in some cases these distinct representations will
result in distinct results in operations defined by IEEE
754.
</div><div class="p">
For datatypes derived from <a href="#precisionDecimal">precisionDecimal</a>, setting the
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits"/> facet is equivalent to restricting
the number of decimal digits available for the significand,
and setting the <a href="#dt-minScale" class="termref"><span class="arrow">·</span>minScale<span class="arrow">·</span></a> and <a href="#dt-maxScale" class="termref"><span class="arrow">·</span>maxScale<span class="arrow">·</span></a> facets amounts to controlling the
possible values of the exponent <var>q</var>.
</div></div><div class="note"><div class="p"><b>Note:</b>
<a href="#precisionDecimal">precisionDecimal</a> also allows the derivation of the Java BigDecimal
class, which corresponds in essentials to a datatype
derived from <a href="#precisionDecimal">precisionDecimal</a> by limiting the allowed scale, by
eliminating the special values, and by ignoring the
difference between +0 and –0.
</div></div><div class="block">Equality and order for <a href="#precisionDecimal">precisionDecimal</a> are defined as
follows:
<ul><li><div class="p">Two numerical <a href="#precisionDecimal">precisionDecimal</a> values are ordered (or
equal) as their <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> values are
ordered (or equal).  (This means that two zeroes with
different <a href="#vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a>
properties are <em>equal</em>;
negative zeroes are <em>not</em> ordered less than
positive zeroes.)</div></li><li><div class="p">INF is equal only to itself, and is greater than
−INF and all numerical <a href="#precisionDecimal">precisionDecimal</a>
values.</div></li><li><div class="p">−INF is equal only to itself, and is less than INF
and all numerical <a href="#precisionDecimal">precisionDecimal</a> values.</div></li><li><div class="p">NaN is <a href="http://www.w3.org/TR/xmlschema11-2/#dt-incomparable">incomparable</a> with all values, <em>including
itself</em>.</div></li></ul>
</div></div><div class="div2">
<h3><span class="nav"><a href="#sec-vs-pD" class="nav"><img alt="previous sub-section" src="previous.jpg"/></a> <a href="#sec-f-pD" class="nav"><img alt="next sub-section" src="next.jpg"/></a></span><a name="pD-lexical-mapping" id="pD-lexical-mapping"/>3.2 Lexical Mapping</h3><div class="block">The lexical space
of <a href="#precisionDecimal">precisionDecimal</a> is the set of all decimal
numerals with or without a decimal point, numerals in scientific
(exponential) notation, and the character strings
'<code>INF</code>', '<code>+INF</code>',
'<code>-INF</code>', and '<code>NaN</code>'.
<div class="defset">
<div class="defset-head">Lexical Space</div>
<div class="prod">
<a name="nt-precDecRep" id="nt-precDecRep"/><span class="lhs">[1]
 
<i>pDecimalRep</i></span> ::= <a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a> | <a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a> |
<a href="http://www.w3.org/TR/xmlschema11-2/#nt-sciNuml">scientificNotationNumeral</a> | <a href="http://www.w3.org/TR/xmlschema11-2/#nt-numSpecReps">numericalSpecialRep</a></div></div>
</div><div class="note"><div class="p"><b>Note:</b> The four non-terminals referred to on the right-hand side
of the <a href="#nt-precDecRep"><i>pDecimalRep</i></a> are defined in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>.
</div></div><div class="block">The <a href="#nt-precDecRep"><i>pDecimalRep</i></a> production is equivalent (after
whitespace is removed) to the following regular expression:
<blockquote class="shrink"><p><code>(\+|-)?([0-9]+(\.[0-9]*)?|\.[0-9]+)([Ee](\+|-)?[0-9]+)?<br/>
|(\+|-)?INF|NaN</code></p></blockquote></div><p>The <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-mapping">lexical mapping</a> for <a href="#precisionDecimal">precisionDecimal</a> is <a href="#f-precDecLexmap"><i><span class="arrow">·</span>precisionDecimalLexicalMap<span class="arrow">·</span></i></a>.  The <a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-mapping">canonical mapping</a> is <a href="#f-precDecCanmap"><i><span class="arrow">·</span>precisionDecimalCanonicalMap<span class="arrow">·</span></i></a>.</p><div class="block">For example, each of the
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a>
shown below is followed by its corresponding value triple
(<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a>, <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>,
and <a href="#vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a>) and <a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-representation">canonical representation</a>:
<ul><li><div class="p">'<code>3</code>'   ( 3 ,  0 , 
<b><i>positive</i></b> )   '<code>3</code>'</div></li><li><div class="p">'<code>3.00</code>'   ( 3 ,  2 , 
<b><i>positive</i></b> )   '<code>3.00</code>'</div></li><li><div class="p">'<code>03.00</code>'   ( 3 ,  2 , 
<b><i>positive</i></b> )   '<code>3.00</code>'</div></li><li><div class="p">'<code>300</code>'   ( 300 ,  0 , 
<b><i>positive</i></b> )   '<code>300</code>'</div></li><li><div class="p">'<code>3.00e2</code>'   ( 300 ,  0 , 
<b><i>positive</i></b> )   '<code>300</code>'</div></li><li><div class="p">'<code>3.0e2</code>'   ( 300 ,  −1 , 
<b><i>positive</i></b> )   '<code>3.0E2</code>'</div></li><li><div class="p">'<code>30e1</code>'   ( 300 ,  −1 , 
<b><i>positive</i></b> )   '<code>3.0E2</code>'</div></li><li><div class="p">'<code>.30e3</code>'   ( 300 ,  −1 , 
<b><i>positive</i></b> )   '<code>3.0E2</code>'</div></li></ul>
Note that the last three examples not only show different
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a>
for the same value, but are of particular interest because
values with negative precision can <em>only</em> have
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a>
in scientific notation.</div><div class="note"><div class="p"><b>Note:</b> <a href="#ieee754-2008">[IEEE 754-2008]</a> expects <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a> whose exact
value is not in the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a> to be mapped to the nearest
value that is in the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a>. When <a href="#precisionDecimal">precisionDecimal</a> is
restricted, all <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a> of values dropped
from the value space are dropped from the lexical space. One
result is that when <a href="#precisionDecimal">precisionDecimal</a> is restricted using the
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits"/> or <a href="#dt-maxScale" class="termref"><span class="arrow">·</span>maxScale<span class="arrow">·</span></a> facets,
non-zero digits beyond those required to exactly represent the
intended value are not permitted by this specification.
</div><div class="p">
<a href="#ieee754-2008">[IEEE 754-2008]</a> permits all case variants of '<code>INF</code>'
and '<code>NaN</code>', as well as those of
'<code>INFINITY</code>'; in many cases it permits language
definitions to prescribe which variants are used. This
specification explicitly chooses only '<code>INF</code>'
and '<code>NaN</code>'. 754 also permits language
definitions to prescribe whether '<code>+</code>' shall be
used with positive values; this specification makes the
'<code>+</code>' optional.</div></div><div class="note"><div class="p"><b>Note:</b>
Note: The <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a> with
"unnecessary least significant digits"
representations are the only ones lost when <a href="#precisionDecimal">precisionDecimal</a> is
restricted; shorter and simpler <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-representation">lexical representations</a>
will not be eliminated by use of
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits"/> or <a href="#dt-maxScale" class="termref"><span class="arrow">·</span>maxScale<span class="arrow">·</span></a>. (In contrast, if facets for
controlling total digits and scale were available for the
floating-point binary types, the effect of restriction
would often be inconvenient. In the floating-point binary
types, a simple decimal numeral will sometimes have no
exact value and so the number will be rounded to a binary
approximation. Any restriction of the value space which
dropped that approximate value would automatically also
drop the simple decimal numeral from the lexical space.
For example, the number one-tenth is in the value space
neither of float nor of double; the string
'<code>0.1</code>' maps, in double, to
0.1000000000000000055511151231257827021181583404541015625.
If the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits"/>, <a href="#dt-minScale" class="termref"><span class="arrow">·</span>minScale<span class="arrow">·</span></a>, and <a href="#dt-maxScale" class="termref"><span class="arrow">·</span>maxScale<span class="arrow">·</span></a>
facets were available for double (they are not) and were
used to define the float type (again, they are not), the
value just mentioned would be dropped, and the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-literal">literal</a>
'<code>0.1</code>' would be dropped along with it,
instead of mapping (as in fact it does) to the value
0.100000001490116119384765625.</div><div class="p">
This interaction between datatype restriction and
rounding has as a consequence that it will typically be
more convenient for users if restricted-precision
numeric types are derived from <a href="#precisionDecimal">precisionDecimal</a> than it would be
if they were derived from
<a href="http://www.w3.org/TR/xmlschema11-2/#float">float</a>
or <a href="http://www.w3.org/TR/xmlschema11-2/#double">double</a>.
</div></div></div><div class="div2">
<h3><span class="nav"><a href="#pD-lexical-mapping" class="nav"><img alt="previous sub-section" src="previous.jpg"/></a> </span><a name="sec-f-pD" id="sec-f-pD"/>3.3 Facets</h3><p><span class=""><span class="">The
<a href="#precisionDecimal">precisionDecimal</a> datatype
and all datatypes derived from it by restriction have the
following <a href="#dt-constraining-facet" class="termref"><span class="arrow">·</span>constraining facets<span class="arrow">·</span></a></span></span> with <b><i>fixed</i></b> values; these
facets <span class="rfc2119">must not</span> be changed from the values shown:</p>
<ul>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-whiteSpace" name="precisionDecimal.whiteSpace">whiteSpace</a><span class=""><span class=""> = <b><i>collapse</i></b> (fixed)</span></span></li>
</ul><p><span class=""><span class="">Datatypes derived by
restriction from <a href="#precisionDecimal">precisionDecimal</a> <span class="rfc2119">may</span> also
specify values for the
following <a href="http://www.w3.org/TR/xmlschema11-2/#dt-constraining-facet" class="termref"><span class="arrow">·</span>constraining facets<span class="arrow">·</span></a>:</span></span></p>
<ul>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-totalDigits">totalDigits</a></li>
<li><a href="#rf-maxScale">maxScale</a></li>
<li><a href="#rf-minScale">minScale</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-pattern">pattern</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-enumeration">enumeration</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-maxInclusive">maxInclusive</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-maxExclusive">maxExclusive</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-minInclusive">minInclusive</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-minExclusive">minExclusive</a></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-assertions">assertions</a></li></ul>
<div class=""><div class=""><p>The
<a href="#precisionDecimal">precisionDecimal</a>
datatype
has the following values for its
<a href="#dt-fundamental-facet" class="termref"><span class="arrow">·</span>fundamental facets<span class="arrow">·</span></a>:
</p>
<ul>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-ordered">ordered</a> = <b><i>partial</i></b></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-bounded">bounded</a> = <b><i>false</i></b></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-cardinality">cardinality</a> = <b><i>countably infinite</i></b></li>
<li><a href="http://www.w3.org/TR/xmlschema11-2/#rf-numeric">numeric</a> = <b><i>true</i></b></li>
</ul>
</div></div></div></div><div class="div1">
<h2><a name="facets" id="facets"/>4 Facets for constraining precisionDecimal values</h2><p>
The
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-assertions">assertions</a>,
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-enumeration">enumeration</a>,
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-maxInclusive">maxInclusive</a>,
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-maxExclusive">maxExclusive</a>,
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-minExclusive">minExclusive</a>,
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-minInclusive">minInclusive</a>,
and
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-pattern">pattern</a>
facets defined by <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a> can be used in
deriving new types from <a href="#precisionDecimal">precisionDecimal</a> by restriction; their meaning and
use are as documented in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>.
</p><p>
The <a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits">totalDigits</a>
facet defined by <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a> can also be
used. Its meaning, when applied to values of type <a href="#precisionDecimal">precisionDecimal</a>, is
described in <a href="#rf-totalDigits">totalDigits (§4.1)</a>. Except as
otherwise specified in <a href="#rf-totalDigits">totalDigits (§4.1)</a>, all
the constraints on the use of the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-totalDigits">totalDigits</a>
facet described in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a> continue
to apply when the facet is used with <a href="#precisionDecimal">precisionDecimal</a> values.
</p><p>
In addition, two facets not defined by
<a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a> can be
used when restricting <a href="#precisionDecimal">precisionDecimal</a>. They are
described in <a href="#rf-maxScale">maxScale (§4.2)</a>
and <a href="#rf-minScale">minScale (§4.3)</a>.
</p><div class="div2">
<h3 class="withToc"><span class="nav"> <a href="#rf-maxScale" class="nav"><img alt="next sub-section" src="next.jpg"/></a></span><a name="rf-totalDigits" id="rf-totalDigits"/>4.1 totalDigits</h3><p>
For <a href="#precisionDecimal">precisionDecimal</a> values with <a href="#vp-pd-numVal" class="vprop"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> of <var>nV</var> and <a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of <var>aP</var>, if the
<a href="http://www.w3.org/TR/xmlschema11-2/#f-td-value">value</a> of
<a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/>
is <var>t</var>, the effect of the <a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/> facet
is to require that (<var>aP</var> + 1 + <span class="eqn">log</span><sub>10</sub>(| <var>nV</var> |)
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-div">div</a> 1) ≤ <var>t</var>, for values other than zero, NaN,
and the infinities. This means in effect that values are
expressible in scientific notation using at most
<var>t</var> digits for the coefficient.
</p><div class="div3">
<h4><a name="totalDigits-validation-rules" id="totalDigits-validation-rules"/>4.1.1 totalDigits Validation Rules</h4><div class="constraintnote"><a id="cvc-totalDigits-valid" name="cvc-totalDigits-valid"/><b>Validation Rule: totalDigits Valid</b><br/><div class="constraint"><div class="p">A <a href="#precisionDecimal">precisionDecimal</a>
value <var>v</var>
is facet-valid with respect to a <a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/> facet with
a <a href="http://www.w3.org/TR/xmlschema11-2/#f-td-value">value</a>
of <var>t</var> if and only
if one of the following is true:
</div><div class="constraintlist"><div class="clnumber">1 <span class="p"><var>v</var> is a <a href="#precisionDecimal">precisionDecimal</a> value with
<a href="#vp-pd-numVal" class="vprop"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> of
<b><i>positiveInfinity</i></b>,
<b><i>negativeInfinity</i></b>, <b><i>notANumber</i></b>,
or zero.
</span></div>
<div class="clnumber">2 <span class="p"><var>v</var> is a <a href="#precisionDecimal">precisionDecimal</a> value with
<a href="#vp-pd-numVal" class="vprop"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> of <var>nV</var> and
<a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of <var>aP</var>,
and <var>v</var> is not NaN, INF, -INF, or zero, and
(<var>aP</var> + 1 + <span class="eqn">log</span><sub>10</sub>(| <var>nV</var> |)
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-div">div</a> 1) ≤ <var>t</var>. </span></div>
</div></div></div></div></div><div class="div2">
<h3 class="withToc"><span class="nav"><a href="#rf-totalDigits" class="nav"><img alt="previous sub-section" src="previous.jpg"/></a> <a href="#rf-minScale" class="nav"><img alt="next sub-section" src="next.jpg"/></a></span><a name="rf-maxScale" id="rf-maxScale"/>4.2 maxScale</h3><div class="localToc">        4.2.1 <a href="#dc-maxScale">The maxScale Schema Component</a><br/>
        4.2.2 <a href="#xr-maxScale">XML Representation of maxScale Schema Components</a><br/>
        4.2.3 <a href="#maxScale-validation-rules">maxScale Validation Rules</a><br/>
        4.2.4 <a href="#maxScale-coss">Constraints on maxScale Schema Components</a><br/>
</div><p>
<span class="termdef"><a name="dt-maxScale" id="dt-maxScale" title="">[Definition:]  </a>
<b>maxScale</b> places an upper limit on the
<a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>
of <a href="#precisionDecimal">precisionDecimal</a> values: if the
<a href="#f-ms-value" class="propref">{value}</a> of <b>maxScale</b> =
<var>m</var>, then only values with
<a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> ≤ <var>m</var>
are retained in
the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a>.</span>
As a consequence, every value in the value space will have
<a href="#vp-pd-numVal" class="vprop"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> equal to
<var>i</var> / 10<sup><var>n</var></sup> for some
integers <var>i</var> and <var>n</var>, with <var>n</var>
≤ <var>m</var>. The <a href="#f-ms-value" class="propref">{value}</a>
of <a href="#f-ms" class="compref">maxScale</a>
<span class="rfc2119">must</span> be an
<a href="http://www.w3.org/TR/xmlschema11-2/#integer">integer</a>.
If it is negative, the numeric values of the datatype are
restricted to multiples of 10 (or 100, or …).
</p><p>
The term 'maxScale' is chosen to reflect
the fact that it restricts the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a> to those values
that can be represented lexically in scientific notation
using an integer coefficient and a scale (or negative
exponent) no greater than <a href="#f-ms" class="compref">maxScale</a>. (It has
nothing to do with the use of the term
'scale' to denote the radix or base of a
notation.) Note that <a href="#f-ms" class="compref">maxScale</a> does not restrict
the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-space">lexical space</a> directly; a lexical representation that
adds non-significant leading or trailing zero digits, or
that uses a lower exponent with a non-integer coefficient is
still permitted.
</p><div class="exampleOuter">
<div class="exampleHeader">Example</div>
<div class="exampleWrapper">
<div class="p">
The following is the definition of a user-defined datatype
which could be used to represent a floating-point decimal
datatype which allows seven decimal digits for the
coefficient and exponents between −95 and 96. Note
that the scale is −1 times the exponent.
</div></div><div class="exampleInner">
<pre>&lt;simpleType name='decimal32'&gt;
&lt;restriction base='precisionDecimal'&gt;
&lt;totalDigits value='7'/&gt;
&lt;maxScale value='95'/&gt;
&lt;minScale value='-96'/&gt;
&lt;/restriction&gt;
&lt;/simpleType&gt;</pre></div></div><div class="div3">
<h4><a name="dc-maxScale" id="dc-maxScale"/>4.2.1 The maxScale Schema Component</h4><div class="schemaComp">
<div class="component">
<div class="compHeader">
<span class="schemaComp">Schema Component: </span><a name="f-ms" id="f-ms">maxScale</a></div>
<div class="compBody">
<div class="propList">
<div class="propDefn"><a name="f-ms-annotations"/><div class="pdName"><span class="propdef">{annotations}</span></div>
<div class="pdDef">
A sequence of <a href="http://www.w3.org/TR/xmlschema11-1/#a" class="compref">Annotation</a> components. </div>
</div>
<div class="propDefn"><a name="f-ms-value"/><div class="pdName"><span class="propdef">{value}</span></div>
<div class="pdDef">
An xs:integer value. Required.</div>
</div>
<div class="propDefn"><a name="f-ms-fixed"/><div class="pdName"><span class="propdef">{fixed}</span></div>
<div class="pdDef">
An xs:boolean value. Required.</div>
</div>
</div></div>
</div>
</div>
<p>
If <a href="#f-ms-fixed" class="propref">{fixed}</a> is <b><i>true</i></b>, then
types for which the current type is the
<a href="http://www.w3.org/TR/xmlschema11-2/#std-base_type_definition" class="propref">{base type definition}</a>
<span class="rfc2119">must not</span> specify a value for <a href="#f-ms" class="compref">maxScale</a> other
than <a href="#f-ms-value" class="propref">{value}</a>.
</p></div><div class="div3">
<h4><a name="xr-maxScale" id="xr-maxScale"/>4.2.2 XML Representation of maxScale Schema Components</h4><p>
The XML representation for a <a href="#f-ms" class="compref">maxScale</a> schema
component is a <a href="http://www.w3.org/TR/xmlschema11-2/#element-maxScale" class="eltref">&lt;maxScale&gt;</a> element information item. The
correspondences between the properties of the information item and
properties of the component are as follows:
</p><div class="reprdef"><div class="reprHeader"><span class="reprdef">XML Representation Summary</span>: <code>maxScale</code> Element Information Item</div><div class="reprBody"><p class="element-syntax-1"/><div class="reprcompmulti"><div class="reprHead"><a href="#dc-maxScale">maxScale</a> <strong>Schema Component</strong></div></div><div class="mapProp"><strong>Property</strong></div><div class="mapRepr"><strong>Representation</strong></div><div class="mapSep"> </div><div class="mapProp"><a href="#f-ms-value" class="propref">{value}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-vv">actual value</a> of the <code>value</code> <a href="http://www.w3.org/TR/xml-infoset/#infoitem.element" class="xpropref">[attribute]</a>
</div><div class="mapSep"> </div><div class="mapProp"><a href="#f-ms-fixed" class="propref">{fixed}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-vv">actual value</a> of the <code>fixed</code> <a href="http://www.w3.org/TR/xml-infoset/#infoitem.element" class="xpropref">[attribute]</a>,
if present, otherwise <b><i>false</i></b>
</div><div class="mapSep"> </div><div class="mapProp"><a href="#f-ms-annotations" class="propref">{annotations}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-am-one">annotation mapping</a> of the
<a href="http://www.w3.org/TR/xmlschema11-2/#element-maxScale" class="eltref">&lt;maxScale&gt;</a>
element, as defined in
section <a href="http://www.w3.org/TR/xmlschema11-1/#declare-annotation">XML Representation of Annotation Schema Components</a>
of <a href="#structures-1.1">[XSD 1.1 Part 1: Structures]</a>.
</div></div></div></div><div class="div3">
<h4><a name="maxScale-validation-rules" id="maxScale-validation-rules"/>4.2.3 maxScale Validation Rules</h4><div class="constraintnote"><a id="cvc-maxScale-valid" name="cvc-maxScale-valid"/><b>Validation Rule: maxScale Valid</b><br/><div class="constraint"><div class="p">
A <a href="#precisionDecimal">precisionDecimal</a> value <var>v</var> is facet-valid with
respect to <a href="#f-ms" class="compref">maxScale</a> if and only if one of the
following is true:
</div><div class="constraintlist"><div class="clnumber">1 <span class="p"><var>v</var> has <a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>
less than or equal to the
<a href="#f-ms-value" class="propref">{value}</a> of <a href="#f-ms" class="compref">maxScale</a>.</span></div>
<div class="clnumber">2 <span class="p">The <a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of <var>v</var>
is <b><i>absent</i></b>.</span></div>
</div></div></div></div><div class="div3">
<h4><a name="maxScale-coss" id="maxScale-coss"/>4.2.4 Constraints on maxScale Schema Components</h4><div class="constraintnote"><a id="maxScale-valid-restriction" name="maxScale-valid-restriction"/><b>Schema Component Constraint: maxScale valid restriction</b><br/><div class="constraint"><div class="p">
It is an <a href="http://www.w3.org/TR/xmlschema11-2/#dt-error">error</a> if <a href="#f-ms" class="compref">maxScale</a> is among the
members of <a href="http://www.w3.org/TR/xmlschema11-2/#std-facets">{facets}</a> of <a href="http://www.w3.org/TR/xmlschema11-2/#std-base_type_definition" class="propref">{base type definition}</a> and <a href="#f-ms-value" class="propref">{value}</a> is greater than the <a href="#f-ms-value" class="propref">{value}</a> of that <a href="#f-ms" class="compref">maxScale</a>.
</div></div></div></div></div><div class="div2">
<h3 class="withToc"><span class="nav"><a href="#rf-maxScale" class="nav"><img alt="previous sub-section" src="previous.jpg"/></a> </span><a name="rf-minScale" id="rf-minScale"/>4.3 minScale</h3><div class="localToc">        4.3.1 <a href="#dc-minScale">The minScale Schema Component</a><br/>
        4.3.2 <a href="#xr-minScale">XML Representation of minScale Schema Components</a><br/>
        4.3.3 <a href="#minScale-validation-rules">minScale Validation Rules</a><br/>
        4.3.4 <a href="#minScale-coss">Constraints on minScale Schema Components</a><br/>
</div><p>
<span class="termdef"><a name="dt-minScale" id="dt-minScale" title="">[Definition:]  </a>
<b>minScale</b> places a lower limit on
the
<a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>
of <a href="#precisionDecimal">precisionDecimal</a> values.
If the <a href="#f-mns-value" class="propref">{value}</a> of <b>minScale</b>
is <var>m</var>, then the value space is restricted to values with
<a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> ≥ <var>m</var>.</span>
As a consequence, every value in the value space will have
<a href="#vp-pd-numVal" class="vprop"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> equal to
<var>i</var> / 10<sup><var>n</var></sup> for some integers
<var>i</var> and <var>n</var>,
with <var>n</var> ≥ <var>m</var>.
</p><p>
The term <b>minScale</b> is chosen to reflect the fact that it
restricts the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a> to those values that can
be represented lexically in exponential form using an integer
coefficient and a scale (negative exponent)
at least as large as <em>minScale</em>. Note that
it does not restrict the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-lexical-space">lexical space</a> directly; a
lexical representation that adds additional leading zero digits,
or that uses a larger exponent (and a correspondingly smaller coefficient)
is still permitted.
</p><div class="exampleOuter">
<div class="exampleHeader">Example</div>
<div class="exampleWrapper">
<div class="p">
The following is the definition of a user-defined
datatype which could be used to represent amounts in a decimal
currency; it corresponds to a SQL column definition of
<code>DECIMAL(8,2)</code>. The effect is to allow values
between -999,999.99 and 999,999.99, with a fixed interval
of 0.01 between values.
</div></div><div class="exampleInner">
<pre>&lt;simpleType name='price'&gt;
&lt;restriction base='precisionDecimal'&gt;
&lt;totalDigits value='8'/&gt;
&lt;minScale value='2'/&gt;
&lt;maxScale value='2'/&gt;
&lt;/restriction&gt;
&lt;/simpleType&gt;</pre></div></div><div class="div3">
<h4><a name="dc-minScale" id="dc-minScale"/>4.3.1 The minScale Schema Component</h4><div class="schemaComp">
<div class="component">
<div class="compHeader">
<span class="schemaComp">Schema Component: </span><a name="f-mns" id="f-mns">minScale</a></div>
<div class="compBody">
<div class="propList">
<div class="propDefn"><a name="f-mns-annotations"/><div class="pdName"><span class="propdef">{annotations}</span></div>
<div class="pdDef">
A sequence of <a href="http://www.w3.org/TR/xmlschema11-1/#a" class="compref">Annotation</a> components. </div>
</div>
<div class="propDefn"><a name="f-mns-value"/><div class="pdName"><span class="propdef">{value}</span></div>
<div class="pdDef">
An xs:integer value. Required.</div>
</div>
<div class="propDefn"><a name="f-mns-fixed"/><div class="pdName"><span class="propdef">{fixed}</span></div>
<div class="pdDef">
An xs:boolean value. Required.</div>
</div>
</div></div>
</div>
</div>
<p>
If <a href="#f-mns-fixed" class="propref">{fixed}</a> is <b><i>true</i></b>, then types for which
the current type is the <a href="http://www.w3.org/TR/xmlschema11-2/#std-base_type_definition" class="propref">{base type definition}</a>
<span class="rfc2119">must not</span> specify a
value for <a href="#f-mns" class="compref">minScale</a> other than
<a href="#f-mns-value" class="propref">{value}</a>.
</p></div><div class="div3">
<h4><a name="xr-minScale" id="xr-minScale"/>4.3.2 XML Representation of minScale Schema Components</h4><p>
The XML representation for a <a href="#f-mns" class="compref">minScale</a> schema
component is a <a href="http://www.w3.org/TR/xmlschema11-2/#element-minScale" class="eltref">&lt;minScale&gt;</a> element information item. The
correspondences between the properties of the information item and
properties of the component are as follows:
</p><div class="reprdef"><div class="reprHeader"><span class="reprdef">XML Representation Summary</span>: <code>minScale</code> Element Information Item</div><div class="reprBody"><p class="element-syntax-1"/><div class="reprcompmulti"><div class="reprHead"><a href="#dc-minScale">minScale</a> <strong>Schema Component</strong></div></div><div class="mapProp"><strong>Property</strong></div><div class="mapRepr"><strong>Representation</strong></div><div class="mapSep"> </div><div class="mapProp"><a href="#f-mns-value" class="propref">{value}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-vv">actual value</a> of the <code>value</code> <a href="http://www.w3.org/TR/xml-infoset/#infoitem.element" class="xpropref">[attribute]</a>
</div><div class="mapSep"> </div><div class="mapProp"><a href="#f-mns-fixed" class="propref">{fixed}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-vv">actual value</a> of the <code>fixed</code> <a href="http://www.w3.org/TR/xml-infoset/#infoitem.element" class="xpropref">[attribute]</a>, if present, otherwise <b><i>false</i></b>
</div><div class="mapSep"> </div><div class="mapProp"><a href="#f-mns-annotations" class="propref">{annotations}</a></div><div class="mapRepr">
The <a href="http://www.w3.org/TR/xmlschema11-1/#key-am-one">annotation mapping</a> of the
<a href="http://www.w3.org/TR/xmlschema11-2/#element-minScale" class="eltref">&lt;minScale&gt;</a>
element, as defined in
section <a href="http://www.w3.org/TR/xmlschema11-1/#declare-annotation">XML Representation of Annotation Schema Components</a>
of <a href="#structures-1.1">[XSD 1.1 Part 1: Structures]</a>.
</div></div></div></div><div class="div3">
<h4><a name="minScale-validation-rules" id="minScale-validation-rules"/>4.3.3 minScale Validation Rules</h4><div class="constraintnote"><a id="cvc-minScale-valid" name="cvc-minScale-valid"/><b>Validation Rule: minScale Valid</b><br/><div class="constraint"><div class="p">
A <a href="#precisionDecimal">precisionDecimal</a> value <var>v</var> is facet-valid with
respect to <a href="#f-mns" class="compref">minScale</a>
if and only if one of the following is true:
</div><div class="constraintlist"><div class="clnumber">1 <span class="p">
<var>v</var> has <a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a>
greater than or equal to
the <a href="#f-mns-value" class="propref">{value}</a>
of <a href="#f-mns" class="compref">minScale</a>.
</span></div>
<div class="clnumber">2 <span class="p">The <a href="#vp-pd-precision" class="vprop"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of <var>v</var>
is <b><i>absent</i></b>.</span></div>
</div></div></div></div><div class="div3">
<h4><a name="minScale-coss" id="minScale-coss"/>4.3.4 Constraints on minScale Schema Components</h4><div class="constraintnote"><a id="minScale-totalDigits" name="minScale-totalDigits"/><b>Schema Component Constraint: minScale less than or equal to maxScale</b><br/><div class="constraint"><div class="p">
It is an <a href="http://www.w3.org/TR/xmlschema11-2/#dt-error">error</a> for <a href="#f-mns" class="compref">minScale</a> to
be greater than <a href="#f-ms" class="compref">maxScale</a>.
</div></div></div><p>Note that it is <em>not</em> an error for <a href="#f-mns" class="compref">minScale</a> to be greater than <a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/>.</p><div class="constraintnote"><a id="minScale-valid-restriction" name="minScale-valid-restriction"/><b>Schema Component Constraint: minScale valid restriction</b><br/><div class="constraint"><div class="p">
It is an <a href="http://www.w3.org/TR/xmlschema11-2/#dt-error">error</a> if <a href="#f-mns" class="compref">minScale</a>
is among the members of <a href="http://www.w3.org/TR/xmlschema11-2/#std-facets">{facets}</a> of
<a href="http://www.w3.org/TR/xmlschema11-2/#std-base_type_definition" class="propref">{base type definition}</a> and
<a href="#f-mns-value" class="propref">{value}</a> is less than the <a href="#f-mns-value" class="propref">{value}</a> of that <a href="#f-mns" class="compref">minScale</a>.
</div></div></div></div></div></div><div class="div1">
<h2><a name="implementation-notes" id="implementation-notes"/>5 Implementation issues</h2><div class="div2">
<h3><span class="nav"> <a href="#implementing-operators" class="nav"><img alt="next sub-section" src="next.jpg"/></a></span><a name="implementation-limits" id="implementation-limits"/>5.1 Implementation limits</h3><p>All <a href="http://www.w3.org/TR/xmlschema11-2/#dt-minimally-conforming">minimally conforming</a> processors <span class="rfc2119">must</span>
support all <a href="#precisionDecimal">precisionDecimal</a> values in the <a href="http://www.w3.org/TR/xmlschema11-2/#dt-value-space">value space</a> of
the otherwise unconstrained <a href="http://www.w3.org/TR/xmlschema11-2/#dt-derived">derived</a> datatype for which
<a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/> is set to sixteen, <a href="#f-ms" class="compref">maxScale</a> to 369,
and <a href="#f-mns" class="compref">minScale</a> to −398.</p><div class="note"><div class="p"><b>Note:</b> The conformance limits given in the text correspond to
those of the decimal64 type defined in <a href="#ieee754-2008">[IEEE 754-2008]</a>, which can be stored in a 64-bit
field. The XML Schema Working Group recommends that
implementors support limits corresponding to those of the
decimal128 type. This entails supporting the values in the
value space of the otherwise unconstrained datatype for which
<a href="http://www.w3.org/TR/xmlschema11-2/#f-td"/> is set to 34, <a href="#f-ms" class="compref">maxScale</a> to
6111, and <a href="#f-mns" class="compref">minScale</a> to
−6176.</div></div></div><div class="div2">
<h3><span class="nav"><a href="#implementation-limits" class="nav"><img alt="previous sub-section" src="previous.jpg"/></a> </span><a name="implementing-operators" id="implementing-operators"/>5.2 Interfacing with XPath</h3><p><a href="#bib-xpath2">[XPath 2.0]</a> does not currently require
support for the precisionDecimal datatype, but conforming
XPath processors are allowed to support additional primitive
data types, including precisionDecimal.
</p><p>
For interoperability, it is recommended that XPath processors
intending to support precisionDecimal as an additional
primitive data type follow the recommendations in <a href="#bib-chamberlin-2006">[Chamberlin 2006]</a>. If the XPath processor used to
evaluate XPath expressions supports precisionDecimal, then any
precisionDecimal values in the <a href="http://www.w3.org/TR/xmlschema11-1/#key-psvi">post-schema-validation infoset</a> <span class="rfc2119">should</span> be labeled as
<code>xs:precisionDecimal</code> in the data model instance
and handled accordingly in XPath.
</p><p>
If the XPath processor does not support precisionDecimal,
then any precisionDecimal values in the <a href="http://www.w3.org/TR/xmlschema11-1/#key-psvi">post-schema-validation infoset</a> <span class="rfc2119">should</span> be
mapped into <a href="http://www.w3.org/TR/xmlschema11-2/#decimal">decimal</a>, unless the
<a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a>
is not a decimal number (for example, it is
<b><i>positiveInfinity</i></b>, <b><i>negativeInfinity</i></b>, or
<b><i>notANumber</i></b>), in which case they <span class="rfc2119">should</span> be mapped
to <a href="http://www.w3.org/TR/xmlschema11-2/#float">float</a>.
Whether this is done by altering the type information in the
partial <a href="http://www.w3.org/TR/xmlschema11-1/#key-psvi">post-schema-validation infoset</a>, or by altering the usual rules for mapping
from a <a href="http://www.w3.org/TR/xmlschema11-1/#key-psvi">post-schema-validation infoset</a> to an <a href="#bib-xdm">[XDM]</a> data model instance,
or by treating precisionDecimal as an unknown type which is
coerced as appropriate into decimal or float by the XPath
processor, is <a href="http://www.w3.org/TR/xmlschema11-2/#key-impl-def">implementation-defined</a> and out of scope for this
specification.
</p><p>
As a consequence of the above variability, it is possible
that XPath expressions that perform various kinds of type
introspections will produce different results when different
XPath processors are used. If the schema author wishes to
ensure interoperable results, such introspections will need to
be avoided.
</p></div></div><div class="div1">
<h2><a name="mappings" id="mappings"/>6 Mapping functions</h2><p>
The functions defined below make frequent reference to
functions defined in <a href="#datatypes-1.1">[XSD 1.1 Part 2: Datatypes]</a>.
</p><div class="defset">
<div class="not_aux">
<div class="defset-head">Auxiliary Functions for Reading Instances of <a href="#nt-precDecRep"><i>pDecimalRep</i></a></div>
<div class="deftop" style="margin-top: 0em;"><b><a name="vp-decPrecision" id="vp-decPrecision"><i><span class="arrow">·</span>decimalPtPrecision<span class="arrow">·</span></i></a></b> (<var>LEX</var>) → integer
<div class="defindent">Maps a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a> onto an integer;
used in calculating the <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of a
<a href="#precisionDecimal">precisionDecimal</a> value.</div>
</div>
<b>Arguments:</b><div class="defindent"><table><tbody>
<tr><td><var>LEX</var></td><td>: </td><td>matches
<a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a>
</td></tr>
</tbody></table></div>
<b>Result:</b><div class="defindent">an integer</div>
<b>Algorithm:</b>
<div class="defindent"><var>LEX</var> necessarily contains a decimal
point ('<code>.</code>') and may optionally contain a
following <a href="http://www.w3.org/TR/xmlschema11-2/#nt-fracFrag">fracFrag</a>
<var>F</var> consisting of some number <var>n</var> of
<a href="http://www.w3.org/TR/xmlschema11-2/#nt-digit">digit</a>s.
</div>
<div class="defindent">Return
<ul><li><div class="p"><var>n</var>   when <var>F</var> is present, and</div></li><li><div class="p">0   otherwise.</div></li></ul>
</div>
<div class="deftop"><b><a name="vp-sciPrecision" id="vp-sciPrecision"><i><span class="arrow">·</span>scientificPrecision<span class="arrow">·</span></i></a></b> (<var>LEX</var>) → integer
<div class="defindent">Maps a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-sciNuml">scientificNotationNumeral</a> onto an integer;
used in calculating the <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of a
<a href="#precisionDecimal">precisionDecimal</a> value.</div>
</div>
<b>Arguments:</b><div class="defindent"><table><tbody>
<tr><td><var>LEX</var></td><td>: </td><td>matches
<a href="http://www.w3.org/TR/xmlschema11-2/#nt-sciNuml">scientificNotationNumeral</a></td></tr>
</tbody></table></div>
<b>Result:</b><div class="defindent">an integer</div>
<b>Algorithm:</b>
<div class="defindent"><var>LEX</var> necessarily contains a
<a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a> or <a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a> <var>C</var>
preceding an exponent indicator ('<code>E</code>' or
'<code>e</code>', and a following <a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a>
<var>E</var>.</div>
<div class="defindent">Return<ul><li><div class="p">−1 × <a href="http://www.w3.org/TR/xmlschema11-2/#f-noDecVal">noDecimalMap</a>(<var>E</var>)   when <var>C</var> is
a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a>, and</div></li><li><div class="p"><a href="#vp-decPrecision"><i><span class="arrow">·</span>decimalPtPrecision<span class="arrow">·</span></i></a>(<var>C</var>) −
<a href="http://www.w3.org/TR/xmlschema11-2/#f-noDecVal">noDecimalMap</a>(<var>E</var>)   otherwise.</div></li></ul>
</div>
</div></div><div class="defset">
<div class="not_aux">
<div class="defset-head">Lexical Mapping</div>
<div class="deftop" style="margin-top: 0em;"><b><a name="f-precDecLexmap" id="f-precDecLexmap"><i><span class="arrow">·</span>precisionDecimalLexicalMap<span class="arrow">·</span></i></a></b> (<var>LEX</var>) → <a href="#precisionDecimal">precisionDecimal</a>
<div class="defindent">Maps a <a href="#nt-precDecRep"><i>pDecimalRep</i></a> onto a complete
<a href="#precisionDecimal">precisionDecimal</a> value.</div>
</div>
<b>Arguments:</b><div class="defindent"><table><tbody>
<tr><td><var>LEX</var></td><td>: </td><td>matches <a href="#nt-precDecRep"><i>pDecimalRep</i></a></td></tr>
</tbody></table></div>
<b>Result:</b><div class="defindent">a <a href="#precisionDecimal">precisionDecimal</a> value</div>
<b>Algorithm:</b>
<div class="defindent"><table><tbody><tr><td valign="top">Let </td><td><var>pD</var> be a complete <a href="#precisionDecimal">precisionDecimal</a>
value.</td></tr></tbody></table></div>
<div class="defindent">
<ol class="enumar"><li><div class="p">Set <var>pD</var>'s <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> to
<ul><li><div class="p"><a href="http://www.w3.org/TR/xmlschema11-2/#f-noDecVal">noDecimalMap</a>(<var>LEX</var>)   when
<var>LEX</var> is an instance of <a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a>,</div></li><li><div class="p"><a href="http://www.w3.org/TR/xmlschema11-2/#f-decVal">decimalPtMap</a>(<var>LEX</var>)   when
<var>LEX</var> is an instance of <a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a>,</div></li><li><div class="p"><a href="http://www.w3.org/TR/xmlschema11-2/#f-sciVal">scientificMap</a>(<var>LEX</var>)   when
<var>LEX</var> is an instance of <a href="http://www.w3.org/TR/xmlschema11-2/#nt-sciNuml">scientificNotationNumeral</a> and</div></li><li><div class="p"><a href="http://www.w3.org/TR/xmlschema11-2/#f-specRepVal">specialRepValue</a>(<var>LEX</var>)   otherwise.</div></li></ul>
</div></li><li><div class="p">Set
<var>pD</var>'s <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> to<ul><li><div class="p">0   when <var>LEX</var> is a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-noDecNuml">noDecimalPtNumeral</a>,</div></li><li><div class="p"><a href="#vp-decPrecision"><i><span class="arrow">·</span>decimalPtPrecision<span class="arrow">·</span></i></a>(<var>LEX</var>)   when <var>LEX</var>
is a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-decNuml">decimalPtNumeral</a>,</div></li><li><div class="p"><a href="#vp-sciPrecision"><i><span class="arrow">·</span>scientificPrecision<span class="arrow">·</span></i></a>(<var>LEX</var>)   when <var>LEX</var>
is a <a href="http://www.w3.org/TR/xmlschema11-2/#nt-sciNuml">scientificNotationNumeral</a>, and</div></li><li><div class="p"><b><i>absent</i></b>   otherwise</div></li></ul>
</div></li><li><div class="p">Set <var>pD</var>'s <a href="#vp-pd-sign"><i><span class="arrow">·</span>sign<span class="arrow">·</span></i></a> to<ul><li><div class="p"><b><i>absent</i></b>   when <var>LEX</var> is '<code>NaN</code>'</div></li><li><div class="p"><b><i>negative</i></b>   when
the first character of <var>LEX</var> is '<code>-</code>', and</div></li><li><div class="p"><b><i>positive</i></b>   otherwise.</div></li></ul></div></li><li><div class="p">Return <var>pD</var>.</div></li></ol>
</div>
</div></div><div class="defset">
<div class="not_aux">
<div class="defset-head">Canonical Mapping</div>
<div class="deftop" style="margin-top: 0em;"><b><a name="f-precDecCanmap" id="f-precDecCanmap"><i><span class="arrow">·</span>precisionDecimalCanonicalMap<span class="arrow">·</span></i></a></b> (<var>pD</var>) → <a href="#nt-precDecRep"><i>pDecimalRep</i></a>
<div class="defindent">Maps a <a href="#precisionDecimal">precisionDecimal</a> to its
<a href="http://www.w3.org/TR/xmlschema11-2/#dt-canonical-representation">canonical representation</a>, a <a href="#nt-precDecRep"><i>pDecimalRep</i></a>.</div>
</div>
<b>Arguments:</b><div class="defindent"><table><tbody>
<tr><td><var>pD</var></td><td>: </td><td>a <a href="#precisionDecimal">precisionDecimal</a> value</td></tr>
</tbody></table></div>
<b>Result:</b><div class="defindent">a <a href="http://www.w3.org/TR/xmlschema11-2/#dt-literal">literal</a> matching <a href="#nt-precDecRep"><i>pDecimalRep</i></a></div>
<b>Algorithm:</b>
<div class="defindent">
<ol class="enumar"><li><div class="p">Let <var>nV</var> be the <a href="#vp-pd-numVal"><i><span class="arrow">·</span>numericalValue<span class="arrow">·</span></i></a> of <var>pD</var>.</div><div class="p">Let <var>aP</var> be the <a href="#vp-pd-precision"><i><span class="arrow">·</span>scale<span class="arrow">·</span></i></a> of <var>pD</var>.</div></li><li><div class="p">If <var>pD</var> is one of NaN, INF, or -INF, then return
<a href="http://www.w3.org/TR/xmlschema11-2/#f-specValCanMap">specialRepCanonicalMap</a>(<var>nV</var>).
</div></li><li><div class="p">Otherwise, if <var>nV</var> is an integer and <var>aP</var> is zero and
1E-6 ≤ <var>nV</var> ≤ 1E6, then return
<a href="http://www.w3.org/TR/xmlschema11-2/#f-noDecCanMap">noDecimalPtCanonicalMap</a>(<var>nV</var>).
</div></li><li><div class="p">Otherwise, if <var>aP</var> is greater than zero and
1E-6 ≤ <var>nV</var> ≤ 1E6, then let <var>s</var> be
<a href="http://www.w3.org/TR/xmlschema11-2/#f-decCanFragMap">decimalPtCanonicalMap</a>(<var>nV</var>).
Let <var>f</var> be the number of fractional digits in <var>s</var>;
<var>f</var> will invariably be less than or equal to <var>aP</var>.
Return the concatenation of <var>s</var> with
<var>aP</var> − <var>f</var>
occurrences of the digit '<code>0</code>'.</div></li><li><div class="p">Otherwise, it will be the case that
<var>nV</var> is less than 1E−6 or greater than 1E6,
or that <var>aP</var> is less than zero. 
Let <ul><li><div class="p"><var>s</var> be
<a href="http://www.w3.org/TR/xmlschema11-2/#f-sciCanFragMap">scientificCanonicalMap</a>(<var>nV</var>).
</div></li><li><div class="p"><var>m</var> be the part of <var>s</var> which precedes the "E".</div></li><li><div class="p"><var>n</var> be the part of <var>s</var> which follows the "E".</div></li><li><div class="p"><var>p</var> be the integer denoted by <var>n</var>.</div></li><li><div class="p"><var>f</var> be the number of fractional digits in <var>m</var>;
note that <var>f</var> will invariably be less than or equal to
<var>aP</var> + <var>p</var>.
</div></li><li><div class="p"><var>t</var> be a string consisting of
<var>aP</var> + <var>p</var> − <var>f</var>
occurrences of the digit '<code>0</code>',
preceded by a decimal point if and only if
<var>m</var> contains no decimal point and
<var>aP</var> + <var>p</var> − <var>f</var> is
greater than zero.</div></li></ul>
Return the concatenation
<var>m</var> &amp; <var>t</var> &amp; '<code>E</code>' &amp; <var>n</var>.
</div></li></ol>
</div>
</div></div></div></div><div class="back"><div class="div1">
<h2><a name="normative-refs" id="normative-refs"/>A Normative references</h2><dl><dt class="label"><a name="ieee754-2008" id="ieee754-2008"/>IEEE 754-2008</dt><dd>
IEEE. <em>IEEE Standard for Floating-Point Arithmetic</em>. 29
August 2008. <a href="http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=4610933">http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=4610933</a>
</dd><dt class="label"><a name="datatypes-1.1" id="datatypes-1.1"/>XSD 1.1 Part 2: Datatypes</dt><dd>
World Wide Web Consortium.
<em>W3C XML Schema Definition Language (XSD) 1.1 Part 2:
Structures</em>,
ed. David Peterson et al.
W3C Working Draft 3 December 2009.
Available at:
<a href="http://www.w3.org/TR/xmlschema11-2/">http://www.w3.org/TR/xmlschema11-2/</a>
</dd></dl></div><div class="div1">
<h2><a name="non-normative-refs" id="non-normative-refs"/>B Non-normative references</h2><dl><dt class="label"><a name="bib-chamberlin-2006" id="bib-chamberlin-2006"/>Chamberlin 2006</dt><dd>
Chamberlin, Don.
<em>Impact of precisionDecimal on XPath and XQuery</em>
Email to the W3C XML Query and W3C XSL Working
Groups, 16 May 2006. Available online at
<a href="http://www.w3.org/XML/2007/dc.pd.xml">http://www.w3.org/XML/2007/dc.pd.xml</a> and <a href="http://www.w3.org/XML/2007/dc.pd.html">http://www.w3.org/XML/2007/dc.pd.html</a>
</dd><dt class="label"><a name="bib-xdm" id="bib-xdm"/>XDM</dt><dd>
World Wide Web Consortium.
<em>XQuery 1.0 and XPath 2.0 Data Model (XDM)</em>,
ed. Mary Fernández et al.
W3C Recommendation 23 January 2007.
Available at:
<a href="http://www.w3.org/TR/xpath-datamodel/">http://www.w3.org/TR/xpath-datamodel/</a>.
</dd><dt class="label"><a name="bib-xpath2" id="bib-xpath2"/>XPath 2.0</dt><dd>
World Wide Web Consortium.
<em>XML Path Language 2.0</em>,
ed. Anders Berglund et al.
23 January 2007.
Available at:
<a href="http://www.w3.org/TR/2007/REC-xpath20-20070123/">http://www.w3.org/TR/2007/REC-xpath20-20070123/</a>
</dd><dt class="label"><a name="structures-1.1" id="structures-1.1"/>XSD 1.1 Part 1: Structures</dt><dd>
World Wide Web Consortium.
<em>W3C XML Schema Definition Language (XSD) 1.1 Part 1:
Structures</em>, ed. Shudi (Sandy) Gao 高殊镝,
C. M. Sperberg-McQueen,
and Henry S. Thompson.
W3C Working Draft 3 December 2009.
Available at:
<a href="http://www.w3.org/TR/xmlschema11-1/">http://www.w3.org/TR/xmlschema11-1/</a>
</dd></dl></div><div class="div1">
<h2><a name="acknowledgments" id="acknowledgments"/>C Acknowledgements (non-normative)</h2><p>This document was prepared by the W3C
XML Schema Working Group. The
members at the time of publication were:</p><ul><li>Gioele Barabucci, University of Bologna</li><li>Paul V. Biron, Invited expert</li><li>David Ezell, National Association of Convenience Stores (NACS) (<i>chair</i>) </li><li>Shudi (Sandy) Gao 高殊镝, IBM</li><li>Mary Holstege, Mark Logic</li><li>Sam Idicula, Oracle</li><li>Michael Kay, Invited expert</li><li>Nan Ma, China Electronics Standardization Institute</li><li>Paolo Marinelli, University of Bologna</li><li>Jim Melton, Oracle</li><li>Noah Mendelsohn, Invited expert</li><li>Dave Peterson, Invited expert</li><li>Liam Quin, W3C</li><li>C. M. Sperberg-McQueen, Black Mesa Technologies (for W3C) (<i>staff contact</i>) </li><li>Henry S. Thompson, University of Edinburgh</li><li>Scott Tsao, The Boeing Company</li><li>Fabio Vitali, University of Bologna</li><li>Stefano Zacchiroli, University of Bologna</li><li>Kongyi Zhou, Oracle</li></ul></div><div class="div1">
<h2><a name="to-do" id="to-do"/>D To-do list (non-normative)</h2><p>Some changes are expected to be made in future work on this document:</p><ul><li><div class="p">Draft fuller introduction.</div></li><li><div class="p">Add section on conformance to this spec.</div></li><li><div class="p">Add section claiming conformance to XSD 1.1 and pointing to the
required information.</div></li></ul></div></div></body>
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