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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>LuaExpat: XML Expat parsing for the Lua programming language</title>
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<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>
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<h1>LuaExpat</h1>
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<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>
<ul>
<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>
</ul>
<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><key>=<value></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 = [[<abc a1="A1" a2="A2">inside tag `abc'</abc>]]
</pre>
<p>A call like</p>
<pre class="example">
tab = lxp.lom.parse (s))
</pre>
<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",
}
</pre>
<p>Now an example with an element nested inside another element</p>
<pre class="example">
tab = lxp.lom.parse(
[[<qwerty q1="q1" q2="q2">
<asdf>some text</asdf>
</qwerty>]]
)
</pre>
<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",
}
</pre>
<p>Note that even the <em>new-line</em> and <em>tab</em> characters are stored
on the table.</p>
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