From 968041a8b2ec86c39b5074024ce97d136ecd9a95 Mon Sep 17 00:00:00 2001 From: Mike Hommey Date: Thu, 26 Oct 2006 11:17:37 +0200 Subject: Load /tmp/libxml2-2.6.27 into libxml2/branches/upstream/current. --- doc/example.html | 70 +++++++++++++++++++++++++++----------------------------- 1 file changed, 34 insertions(+), 36 deletions(-) (limited to 'doc/example.html') diff --git a/doc/example.html b/doc/example.html index 194f619..894f03a 100644 --- a/doc/example.html +++ b/doc/example.html @@ -7,11 +7,11 @@ H1 {font-family: Verdana,Arial,Helvetica} H2 {font-family: Verdana,Arial,Helvetica} H3 {font-family: Verdana,Arial,Helvetica} A:link, A:visited, A:active { text-decoration: underline } -A real example
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Here is a real size example, where the actual content of -theapplicationdata is not kept in the DOM tree but uses internal structures. -Itis based ona proposal to keep a database of jobs related to Gnome, with -anXML basedstorage structure. Here is an XML -encodedjobsbase:

<?xml version="1.0"?>
+A real example
Action against software patentsGnome2 LogoW3C LogoRed Hat Logo
Made with Libxml2 Logo
The XML C parser and toolkit of Gnome
A real example
Developer Menu
API Indexes
Related links
Here is a real size example, where the actual content of the application
+data is not kept in the DOM tree but uses internal structures. It is based on
+a proposal to keep a database of jobs related to Gnome, with an XML based
+storage structure. Here is an XML encoded jobs
+base:
<?xml version="1.0"?>
 <gjob:Helping xmlns:gjob="http://www.gnome.org/some-location">
   <gjob:Jobs>
 
@@ -66,14 +66,13 @@ encodedjobsbase:
<?xml version="1.0"?>
     </gjob:Job>
 
   </gjob:Jobs>
-</gjob:Helping>
While loading the XML file into an internal DOM tree is a matter
-ofcallingonly a couple of functions, browsing the tree to gather the data
-andgeneratethe internal structures is harder, and more error prone.
The suggested principle is to be tolerant with respect to
-theinputstructure. For example, the ordering of the attributes is
-notsignificant,the XML specification is clear about it. It's also usually a
-goodidea not todepend on the order of the children of a given node, unless
-itreally makesthings harder. Here is some code to parse the information for
-aperson:
/*
+</gjob:Helping>
While loading the XML file into an internal DOM tree is a matter of
+calling only a couple of functions, browsing the tree to gather the data and
+generate the internal structures is harder, and more error prone.
The suggested principle is to be tolerant with respect to the input
+structure. For example, the ordering of the attributes is not significant,
+the XML specification is clear about it. It's also usually a good idea not to
+depend on the order of the children of a given node, unless it really makes
+things harder. Here is some code to parse the information for a person:
/*
  * A person record
  */
 typedef struct person {
@@ -114,22 +113,21 @@ DEBUG("parsePerson\n");
     }
 
     return(ret);
-}
Here are a couple of things to notice:
  • Usually a recursive parsing style is the more convenient one: XMLdatais
-    by nature subject to repetitive constructs and usually
-    exhibitshighlystructured patterns.
    • 
-  
  • The two arguments of type xmlDocPtrand
-    xmlNsPtr,i.e.the pointer to the global XML document and the
-    namespace reserved totheapplication. Document wide information are needed
-    for example todecodeentities and it's a good coding practice to define a
-    namespace foryourapplication set of data and test that the element and
-    attributesyou'reanalyzing actually pertains to your application space.
-    This isdone by asimple equality test (cur->ns == ns).
    • 
-  
  • To retrieve text and attributes value, you can use
-    thefunctionxmlNodeListGetStringto gather all the text and
-    entityreferencenodes generated by the DOM output and produce an single
-    textstring.
    • 
-
Here is another piece of code used to parse another level
-ofthestructure:
#include <libxml/tree.h>
+}
Here are a couple of things to notice:
  • Usually a recursive parsing style is the more convenient one: XML data
+    is by nature subject to repetitive constructs and usually exhibits highly
+    structured patterns.
    • 
+  
  • The two arguments of type xmlDocPtr and xmlNsPtr,
+    i.e. the pointer to the global XML document and the namespace reserved to
+    the application. Document wide information are needed for example to
+    decode entities and it's a good coding practice to define a namespace for
+    your application set of data and test that the element and attributes
+    you're analyzing actually pertains to your application space. This is
+    done by a simple equality test (cur->ns == ns).
    • 
+  
  • To retrieve text and attributes value, you can use the function
+    xmlNodeListGetString to gather all the text and entity reference
+    nodes generated by the DOM output and produce an single text string.
    • 
+
Here is another piece of code used to parse another level of the
+structure:
#include <libxml/tree.h>
 /*
  * a Description for a Job
  */
@@ -179,10 +177,10 @@ DEBUG("parseJob\n");
     }
 
     return(ret);
-}
Once you are used to it, writing this kind of code is quite
-simple,butboring. Ultimately, it could be possible to write stubbers taking
-eitherCdata structure definitions, a set of XML examples or an XML DTD
-andproducethe code needed to import and export the content between C data
-andXMLstorage. This is left as an exercise to the reader :-)
Feel free to use the code for the
-fullCparsing exampleas a template, it is also available with Makefile
-intheGnome CVS base under gnome-xml/example
Daniel Veillard

+}

Once you are used to it, writing this kind of code is quite simple, but +boring. Ultimately, it could be possible to write stubbers taking either C +data structure definitions, a set of XML examples or an XML DTD and produce +the code needed to import and export the content between C data and XML +storage. This is left as an exercise to the reader :-)

Feel free to use the code for the full C +parsing example as a template, it is also available with Makefile in the +Gnome CVS base under gnome-xml/example

Daniel Veillard

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