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A small patch and more doc, Daniel.

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Daniel Veillard 1998-10-28 01:00:12 +00:00
parent baf4cd58df
commit 10c6a8fdde
3 changed files with 93 additions and 10 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
Tue Oct 27 17:54:00 EST 1998 Daniel Veillard <Daniel.Veillard@w3.org>
* tree.c: corrected a small bug
* doc/xml.html: continuing writing documentation.
Tue Oct 27 17:54:00 EST 1998 Daniel Veillard <Daniel.Veillard@w3.org>
* debugXML.h debugXML.c: added debugging utilities.

96
doc/xml.html
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@ -17,8 +17,8 @@ href="http://www.w3.org/DOM/">DOM</a> interfaces.</p>
<h2>xml</h2>
<p>
XML is a standard for markup based structured documents, here is an
example:</p>
XML is a standard for markup based structured documents, here is <a
name="example">an example</a>:</p>
<pre>&lt;?xml version="1.0"?>
&lt;EXAMPLE prop1="gnome is great" prop2="&amp;linux; too">
&lt;head>
@ -32,9 +32,12 @@ example:</p>
&lt;/chapter>
&lt;/EXAMPLE></pre>
<p>
</p>
<h2>Invoking the parser</h2>
The first line specify that it's an XML document and gives useful informations
about it's encoding. Then the document is a text format whose structure is
specified by tags between brackets. <strong>Each tag opened have to be
closed</strong> XML is pedantic about this, not that for example the image
tage has no content (just an attribute) and is closed by ending up the tag
with <code>/></code>.</p>
<h2>The tree output</h2>
<p>
@ -53,13 +56,88 @@ one ELEMENT under the root):</p>
<p>
<img src="structure.gif" alt=" structure.gif "></p>
<p>
</p>
In the source package there is a small program (not installed by default)
called <strong>tester</strong> which parses XML files given as argument and
prints them back as parsed, this is useful to detect errors both in XML code
and in the XML parser itself. It has an option <strong>--debug</strong> which
prints the actual in-memory structure of the document, here is the result with
the <a href="#example">example</a> given before:</p>
<pre>DOCUMENT
version=1.0
standalone=true
ELEMENT EXAMPLE
ATTRIBUTE prop1
TEXT
content=gnome is great
ATTRIBUTE prop2
ENTITY_REF
TEXT
content= too
ELEMENT head
ELEMENT title
content=Welcome to Gnome
ELEMENT chapter
ELEMENT title
content=The Linux adventure
ELEMENT p
content=bla bla bla ...
ELEMENT image
ATTRIBUTE href
TEXT
content=linus.gif
ELEMENT p
content=...</pre>
<p>
This should be useful to learn the internal representation model.</p>
<h2>Modifying the tree</h2>
<h2>The XML library interfaces</h2>
<p>
This section is directly intended to help programmers getting bootstrapped
using the XML library from the C language. It doesn't intent to be extensive,
I hope the automatically generated docs will provide the completeness
required, but as a separated set of documents. The interfaces of the XML
library are by principle low level, there is nearly zero abstration. Those
interested in a higher level API should <a href="#DOM">look at DOM</a>
(unfortunately not completed).</p>
<h2>Saving a tree</h2>
<h3>Invoking the parser</h3>
<p>
Usually, the first thing to do is to read an XML input, the parser accepts to
parse both memory mapped documents or direct files. The functions are defined
in "parser.h":</p>
<dl>
<dt>xmlDocPtr xmlParseMemory(char *buffer, int size);</dt>
<dd><p>
parse a zero terminated string containing the document</p>
</dd>
</dl>
<dl>
<dt>xmlDocPtr xmlParseFile(const char *filename);</dt>
<dd><p>
parse an XML document contained in a file (possibly compressed)</p>
</dd>
</dl>
<p>
This returns a pointer to the document structure (or NULL in case of
failure).</p>
<p>
A couple of comments can be made, first this mean that the parser is
memory-hungry, first to load the document in memory, second to build the tree.
Reading a document without building the tree will be possible in the future by
pluggin the code to the SAX interface (see SAX.c).</p>
<h2>DOM interfaces</h2>
<h3>Traversing the tree</h3>
<p>
Basically by including "tree.h" your code has access to the internal structure
of all the element of the tree. The names should be somewhat simple like
<strong>parent</strong>, <strong>childs</strong>, <strong>next</strong>,
<strong>prev</strong>, <strong>properties</strong>, etc... </p>
<h3>Modifying the tree</h3>
<h3>Saving a tree</h3>
<h2><a name="DOM">DOM interfaces</a></h2>
<p>
<a href="http://www.w3.org/DOM/">DOM</a> stands for the <em>Document Object
Model</em> this is an API for accessing XML or HTML structured documents.

2
tree.c
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@ -747,7 +747,7 @@ xmlNewReference(xmlDocPtr doc, const CHAR *name) {
}
cur->type = XML_ENTITY_REF_NODE;
cur->doc = NULL;
cur->doc = doc;
cur->parent = NULL;
cur->next = NULL;
cur->prev = NULL;