<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><strong>Examples</strong></li>

<li><a href="lom.html">Lua Object Model</a></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="examples"></a>Examples</h2>

<p>The code excerpt below creates a parser with 2 callbacks and

feeds a test string to it. The parsing of the test string triggers

the callbacks, printing the results.</p>

<pre class="example">

require"lxp"

local count = 0

callbacks = {

StartElement = function (parser, name)

io.write("+ ", string.rep(" ", count), name, "\n")

count = count + 1

end,

EndElement = function (parser, name)

count = count - 1

io.write("- ", string.rep(" ", count), name, "\n")

end

}

p = lxp.new(callbacks)

for l in io.lines() do -- iterate lines

p:parse(l) -- parses the line

p:parse("\n") -- parses the end of line

end

p:parse() -- finishes the document

p:close() -- closes the parser

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

<pre class="example">

&lt;elem1&gt;

text

&lt;elem2/&gt;

more text

&lt;/elem1&gt;

<p>The example would print</p>

<pre class="example">

+ elem1

+ elem2

- elem2

- elem1

<p>Note that the text parts are not handled since the corresponding

callback (<em>CharacterData</em>) has not been defined. Also note

that defining this callback after the call to lxp.new would make no

difference. But had the callback table been defined as</p>

<pre class="example">

callbacks = {

StartElement = function (parser, name)

io.write("+ ", string.rep(" ", count), name, "\n")

count = count + 1

end,

EndElement = function (parser, name)

count = count - 1

io.write("- ", string.rep(" ", count), name, "\n")

end,

CharacterData = function (parser, string)

io.write("* ", string.rep(" ", count), string, "\n")

end

}

<p>The results would have been</p>

<pre class="example">

+ elem1

* text

+ elem2

- elem2

* more text

- elem1

<p>Another example would be the use of <em>false</em> as a

placeholder for the callback. Suppose that we would like to print

only the text associated with <em>elem2</em> elements and that the

XML sample is</p>

<pre class="example">

&lt;elem1&gt;

text

&lt;elem2&gt;

inside text

&lt;/elem2&gt;

more text

&lt;/elem1&gt;

<p>We could define the new callback table as</p>

<pre class="example">

callbacks = {

StartElement = function (parser, name)

if name == "elem2" then

-- redefines CharacterData behaviour

callbacks.CharacterData = function (parser, string)

io.write(string, "\n")

end

end

end,

EndElement = function (parser, name)

if name == "elem2" then

callbacks.CharacterData = false -- restores placeholder

end

end,

CharacterData = false -- placeholder

}

<p>The results would have been</p>

<pre class="example">

inside text

<p>Note that this example assumes no other elements are present

inside elem2 tags.</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: examples.html,v 1.5 2006/03/23 00:19:37 carregal Exp $

</small></p>

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

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

</html>