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CXML/doc/dom.html
2005-12-29 00:31:30 +00:00

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<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Closure XML</title>
<link rel="stylesheet" type="text/css" href="cxml.css"/>
</head>
<body>
<div class="sidebar">
<p>
<a href="../README.html">CXML Homepage</a>
</p>
<ul class="main">
<li>
<a href="installation.html">Installing Closure XML</a>
<ul class="sub">
<li><a href="installation.html#download"><b>Download</b></a></li>
<li><a href="installation.html#implementations">Implementation-specific notes</a></li>
<li><a href="installation.html#compilation">Compilation</a></li>
<li><a href="installation.html#tests">Tests</a></li>
</ul>
</li>
<li>
<ul class="hack">
<li>
<a href="quickstart.html"><b>Quick-Start Example</b></a>
</li>
</ul>
</li>
<li>
<a href="using.html">SAX parser</a>
<ul class="sub">
<li><a href="using.html#parser">Parsing and Validating</a></li>
<li><a href="using.html#serialization">Serialization</a></li>
<li><a href="using.html#misc">Miscellaneous SAX handlers</a></li>
<li><a href="using.html#rods">Recoders</a></li>
<li><a href="using.html#dtdcache">Caching of DTD Objects</a></li>
<li><a href="using.html#catalogs">XML Catalogs</a></li>
<li><a href="using.html#sax">SAX Interface</a></li>
</ul>
</li>
<li>
<a href="using.html">DOM implementation</a>
<ul class="sub">
<li><a href="dom.html#parser">Parsing with the DOM builder</a></li>
<li><a href="dom.html#serialization">Serialization</a></li>
<li><a href="dom.html#mapping">DOM/Lisp mapping</a></li>
</ul>
</li>
<li>
<ul class="hack">
<li><a href="xmls-compat.html">XMLS Builder</a></li>
</ul>
</li>
</ul>
</div>
<h1>The DOM implementation</h1>
<p>
CXML implements the DOM Level 2 Core interfaces.&nbsp; For details
on DOM, please refer to the <a
href="http://www.w3.org/TR/DOM-Level-2-Core/core.html">specification</a>.
</p>
<a name="parser"/>
<h3>Parsing into DOM</h3>
<p>
To parse an XML document into a DOM tree, use the SAX parser with a
DOM builder as the SAX handler. Example:
</p>
<pre>(cxml:parse-file "test.xml" (cxml-dom:make-dom-builder))</pre>
<p>
<div class="def">Function CXML-DOM:MAKE-DOM-BUILDER ()</div>
Create a SAX handler which builds a DOM document.
<p>
</p>
This functions returns a DOM builder that will work with the default
configuration of the SAX parser and is guaranteed to use
characters/strings instead of runes/rods, if that makes a
difference on the Lisp in question.
<p>
</p>
This is the same as <tt>rune-dom:make-dom-builder</tt> on Lisps
with Unicode support, and the same as
<tt>utf8-dom:make-dom-builder</tt> otherwise.
</p>
<p>
<div class="def">Function RUNE-DOM:MAKE-DOM-BUILDER ()</div>
Create a SAX handler which builds a DOM document using runes and rods.
</p>
<p>
<div class="def">Function UTF8-DOM:MAKE-DOM-BUILDER ()</div>
(Only on Lisps without Unicode support:)
Create a SAX handler which builds a DOM document using
UTF-8-encoded strings.
</p>
<a name="serialization"/>
<h3>Serializing DOM</h3>
<p>
To serialize a DOM document, use a SAX serialization sink as the
argument to <tt>dom:map-document</tt>, which generates SAX events
for the DOM tree.
</p>
<p>
Applications dealing with namespaces might want to inject a
<a href="using.html#misc">namespace normalizer</a> into the
sink chain.
</p>
<p>
<div class="def">Function DOM:MAP-DOCUMENT (handler document &key include-xmlns-attributes include-default-values include-doctype)</div>
Traverse a DOM document and call SAX functions as if an XML
representation of the document was processed by a SAX parser.
</p>
<p>Keyword arguments:</p>
<ul>
<li>
<tt>include-xmlns-attributes</tt> -- defaults to
<tt>sax:*include-xmlns-attributes*</tt>
</li>
<li>
<tt>include-doctype</tt> -- One of <tt>nil</tt> (no doctype
declaration), <tt>:full-internal-subset</tt> (include a doctype
declaration and the full internal subset), or
<tt>:canonical-notations</tt> (write a doctype declaration
with an internal subset including only notations, as required
for canonical serialization).
</li>
<li>
<tt>include-default-values</tt> -- include attribute nodes with nil
<tt>dom:specified</tt>.
</li>
<li>
<tt>recode</tt> -- (ignored on Lisps with Unicode support.) If
true, recode UTF-8 strings to rods. Defaults to true if used
with a UTF-8 DOM document. It can be set to false manually to
suppress recoding in this case.
</li>
</ul>
<a name="mapping"/>
<h3>DOM/Lisp mapping</h3>
<p>
Note that there is no "standard" DOM mapping for Lisp.
</p>
<p>
DOM is <a
href="http://www.w3.org/TR/DOM-Level-2-Core/idl-definitions.html">specified
in CORBA IDL</a>, but it refrains from using object-oriented IDL
features, allowing for a much more natural Lisp implemenation than
the the ordinary IDL/Lisp mapping would.&nbsp;
Differences between CXML's DOM and the direct IDL/Lisp mapping:
</p>
<ul>
<li>
DOM function names are symbols in the <tt>DOM</tt> package (not
the <tt>OP</tt> package).
</li>
<li>
DOM functions have proper required arguments, not a huge
<tt>&rest</tt> lambda list.
</li>
<li>
Although most IDL interfaces are implemented as CLOS classes by
CXML, the Lisp types of DOM objects is not documented and cannot
be relied upon.&nbsp; A node's type can be determined using
<tt>dom:node-type</tt> instead.
</li>
<li>
<tt>DOMString</tt> is mapped to <tt>rod</tt>, which is either
an <tt>(unsigned-byte 16)</tt> array type or a string type.
</li>
<li>
The IDL/Lisp mapping maps CORBA enums to Lisp keywords.&nbsp;
Unfortunately, the DOM IDL does not use enums.&nbsp; Instead,
both exception types and node types are defined integer
constants.&nbsp; CXML chooses to ignore this definition and uses
keywords instead.
</li>
<li>
DOM uses StudlyCaps.&nbsp; Lisp programmers don't.&nbsp; We
insert <tt>#\-</tt> before every upper case letter preceded by a
lower case letter and before every upper case letter which is
followed by a lower case letter, but preceded by a capital
letter.&nbsp; This algorithms leads to the natural Lisp spelling
of DOM function names.
</li>
<li>
Implementation note: DOM's <tt>NodeList</tt> does not
necessarily map to a native "sequence" type.&nbsp; (For example,
node lists are objects in Java, not arrays.)&nbsp;
<tt>NodeList</tt> is specified to reflect changes done after a
node list was created, so node lists cannot be Lisp lists.&nbsp;
(A node list could be implemented as a CLOS object pointing to
said list though.)&nbsp; Instead, CXML currently implements node
lists as adjustable vectors.&nbsp; Note that code which relies on
this implementation and uses Lisp sequence functions
instead of sticking to <tt>dom:item</tt> and <tt>dom:length</tt>
is not portable.&nbsp; As a compromise, you can use our
extensions <tt>dom:map-node-list</tt> or
<tt>dom:do-node-list</tt>, which can be implemented portably.
</li>
</ul>
</body>
</html>