<title>LuaExpat: XML Expat parsing for the Lua programming language</title>

<link rel="stylesheet" href="http://www.keplerproject.org/doc.css" type="text/css"/>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>

<div id="container">

<div id="product">

<div id="product_logo"><a href="http://www.keplerproject.org">

<img alt="LuaExpat logo" src="luaexpat.png"/>

</a></div>

<div id="product_name"><big><strong>LuaExpat</strong></big></div>

<div id="product_description">XML Expat parsing for the Lua programming language</div>

</div> <!-- id="product" -->

<div id="main">

<div id="navigation">

<h1>LuaExpat</h1>

<ul>

<li><a href="index.html">Home</a>

<ul>

<li><a href="index.html#overview">Overview</a></li>

<li><a href="index.html#status">Status</a></li>

<li><a href="index.html#download">Download</a></li>

<li><a href="index.html#history">History</a></li>

<li><a href="index.html#references">References</a></li>

<li><a href="index.html#credits">Credits</a></li>

<li><a href="index.html#contact">Contact</a></li>

</ul>

</li>

<li><a href="manual.html">Manual</a>

<ul>

<li><a href="manual.html#introduction">Introduction</a></li>

<li><a href="manual.html#installation">Installation</a></li>

<li><a href="manual.html#parser">Parser Objects</a></li>

</ul>

</li>

<li><a href="examples.html">Examples</a></li>

<li><strong>Lua Object Model</strong></li>

<li><a href="http://luaforge.net/projects/luaexpat/">Project</a>

<ul>

<li><a href="http://luaforge.net/tracker/?group_id=13">Bug Tracker</a></li>

<li><a href="http://luaforge.net/scm/?group_id=13">CVS</a></li>

</ul>

</li>

<li><a href="license.html">License</a></li>

</ul>

</div> <!-- id="navigation" -->

<div id="content">

<h2><a name="introduction"></a>Introduction</h2>

<p>Lua Object Model (LOM) is a representation of XML elements

through Lua data types. Currently it is not supposed to be 100%

complete, but simple.</p>

<p>LuaExpat's distribution provides an implementation of LOM that

gets an XML documenta (a string) and transforms it to a Lua table.

The only function exported is <strong><code>lxp.lom.parse</code></strong>.</p>

<h2><a name="characteristics"></a>Characteristics</h2>

<p>The model represents each XML element as a Lua table. A LOM

table has three special characteristics:</p>

<li>a special field called <strong><code>tag</code></strong> that holds the

element's name;</li>

<li>an optional field called <strong><code>attr</code></strong> that stores

the element's attributes (see <a href="#attributes">attribute's

section</a>); and</li>

<li>the element's children are stored at the <em>array-part</em> of

the table. A child could be an ordinary string or another XML

element that will be represented by a Lua table following these

same rules.</li>

<h3><a name="attributes"></a>Attributes</h3>

<p>The special field <strong><code>attr</code></strong> is a Lua table that

stores the XML element's attributes as pairs

<em>&lt;key&gt;=&lt;value&gt;</em>. To assure an order (if

necessary), the sequence of <em>key</em>s could be placed at the

<em>array-part</em> of this same table.</p>

<h2><a name="examples"></a>Examples</h2>

<p>For a simple string like</p>

<pre class="example">

s = [[&lt;abc a1="A1" a2="A2"&gt;inside tag `abc'&lt;/abc&gt;]]

<p>A call like</p>

<pre class="example">

tab = lxp.lom.parse (s))

<p>Would result in a table equivalent to</p>

<pre class="example">

tab = {

["attr"] = {

[1] = "a1",

[2] = "a2",

["a2"] = "A2",

["a1"] = "A1",

},

[1] = "inside tag `abc'",

["tag"] = "abc",

}

<p>Now an example with an element nested inside another element</p>

<pre class="example">

tab = lxp.lom.parse(

[[&lt;qwerty q1="q1" q2="q2"&gt;

&lt;asdf&gt;some text&lt;/asdf&gt;

&lt;/qwerty&gt;]]

)

<p>The result would have been a table equivalent to</p>

<pre class="example">

tab = {

[1] = "\

",

[2] = {

["attr"] = {

},

[1] = "some text",

["tag"] = "asdf",

},

["attr"] = {

[1] = "q1",

[2] = "q2",

["q2"] = "q2",

["q1"] = "q1",

},

[3] = "\

",

["tag"] = "qwerty",

}

<p>Note that even the <em>new-line</em> and <em>tab</em> characters are stored

on the table.</p>

</div> <!-- id="content" -->

</div> <!-- id="main" -->

<div id="about">

<p><a href="http://validator.w3.org/check?uri=referer"><img src="http://www.w3.org/Icons/valid-xhtml10" alt="Valid XHTML 1.0!" height="31" width="88" /></a></p>

<p><small>

$Id: lom.html,v 1.6 2006/03/20 22:26:00 carregal Exp $

</small></p>

</div> <!-- id="about" -->

</div> <!-- id="container" -->

</html>