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comparison: doc/us/lom.html

doc/us/lom.html

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1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3 <html>
4 <head>
5 <title>LuaExpat: XML Expat parsing for the Lua programming language</title>
6 <link rel="stylesheet" href="http://www.keplerproject.org/doc.css" type="text/css"/>
7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
8 </head>
9 <body>
10
11 <div id="container">
12
13 <div id="product">
14 <div id="product_logo"><a href="http://www.keplerproject.org">
15 <img alt="LuaExpat logo" src="luaexpat.png"/>
16 </a></div>
17 <div id="product_name"><big><strong>LuaExpat</strong></big></div>
18 <div id="product_description">XML Expat parsing for the Lua programming language</div>
19 </div> <!-- id="product" -->
20
21 <div id="main">
22
23 <div id="navigation">
24 <h1>LuaExpat</h1>
25 <ul>
26 <li><a href="index.html">Home</a>
27 <ul>
28 <li><a href="index.html#overview">Overview</a></li>
29 <li><a href="index.html#status">Status</a></li>
30 <li><a href="index.html#download">Download</a></li>
31 <li><a href="index.html#history">History</a></li>
32 <li><a href="index.html#references">References</a></li>
33 <li><a href="index.html#credits">Credits</a></li>
34 <li><a href="index.html#contact">Contact</a></li>
35 </ul>
36 </li>
37 <li><a href="manual.html">Manual</a>
38 <ul>
39 <li><a href="manual.html#introduction">Introduction</a></li>
40 <li><a href="manual.html#installation">Installation</a></li>
41 <li><a href="manual.html#parser">Parser Objects</a></li>
42 </ul>
43 </li>
44 <li><a href="examples.html">Examples</a></li>
45 <li><strong>Lua Object Model</strong></li>
46 <li><a href="http://luaforge.net/projects/luaexpat/">Project</a>
47 <ul>
48 <li><a href="http://luaforge.net/tracker/?group_id=13">Bug Tracker</a></li>
49 <li><a href="http://luaforge.net/scm/?group_id=13">CVS</a></li>
50 </ul>
51 </li>
52 <li><a href="license.html">License</a></li>
53 </ul>
54 </div> <!-- id="navigation" -->
55
56 <div id="content">
57
58 <h2><a name="introduction"></a>Introduction</h2>
59
60 <p>Lua Object Model (LOM) is a representation of XML elements
61 through Lua data types. Currently it is not supposed to be 100%
62 complete, but simple.</p>
63
64 <p>LuaExpat's distribution provides an implementation of LOM that
65 gets an XML documenta (a string) and transforms it to a Lua table.
66 The only function exported is <strong><code>lxp.lom.parse</code></strong>.</p>
67
68
69 <h2><a name="characteristics"></a>Characteristics</h2>
70
71 <p>The model represents each XML element as a Lua table. A LOM
72 table has three special characteristics:</p>
73
74 <ul>
75 <li>a special field called <strong><code>tag</code></strong> that holds the
76 element's name;</li>
77
78 <li>an optional field called <strong><code>attr</code></strong> that stores
79 the element's attributes (see <a href="#attributes">attribute's
80 section</a>); and</li>
81
82 <li>the element's children are stored at the <em>array-part</em> of
83 the table. A child could be an ordinary string or another XML
84 element that will be represented by a Lua table following these
85 same rules.</li>
86 </ul>
87
88
89 <h3><a name="attributes"></a>Attributes</h3>
90
91 <p>The special field <strong><code>attr</code></strong> is a Lua table that
92 stores the XML element's attributes as pairs
93 <em>&lt;key&gt;=&lt;value&gt;</em>. To assure an order (if
94 necessary), the sequence of <em>key</em>s could be placed at the
95 <em>array-part</em> of this same table.</p>
96
97
98 <h2><a name="examples"></a>Examples</h2>
99
100 <p>For a simple string like</p>
101
102 <pre class="example">
103 s = [[&lt;abc a1="A1" a2="A2"&gt;inside tag `abc'&lt;/abc&gt;]]
104 </pre>
105
106 <p>A call like</p>
107
108 <pre class="example">
109 tab = lxp.lom.parse (s))
110 </pre>
111
112 <p>Would result in a table equivalent to</p>
113
114 <pre class="example">
115 tab = {
116 ["attr"] = {
117 [1] = "a1",
118 [2] = "a2",
119 ["a2"] = "A2",
120 ["a1"] = "A1",
121 },
122 [1] = "inside tag `abc'",
123 ["tag"] = "abc",
124 }
125 </pre>
126
127 <p>Now an example with an element nested inside another element</p>
128
129 <pre class="example">
130 tab = lxp.lom.parse(
131 [[&lt;qwerty q1="q1" q2="q2"&gt;
132 &lt;asdf&gt;some text&lt;/asdf&gt;
133 &lt;/qwerty&gt;]]
134 )
135 </pre>
136
137 <p>The result would have been a table equivalent to</p>
138
139 <pre class="example">
140 tab = {
141 [1] = "\
142 ",
143 [2] = {
144 ["attr"] = {
145 },
146 [1] = "some text",
147 ["tag"] = "asdf",
148 },
149 ["attr"] = {
150 [1] = "q1",
151 [2] = "q2",
152 ["q2"] = "q2",
153 ["q1"] = "q1",
154 },
155 [3] = "\
156 ",
157 ["tag"] = "qwerty",
158 }
159 </pre>
160
161 <p>Note that even the <em>new-line</em> and <em>tab</em> characters are stored
162 on the table.</p>
163
164 </div> <!-- id="content" -->
165
166 </div> <!-- id="main" -->
167
168 <div id="about">
169 <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>
170 <p><small>
171 $Id: lom.html,v 1.6 2006/03/20 22:26:00 carregal Exp $
172 </small></p>
173 </div> <!-- id="about" -->
174
175 </div> <!-- id="container" -->
176
177 </body>
178 </html>

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