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author | William M. Brack <wbrack@src.gnome.org> | 2004-07-03 09:53:08 +0000 |
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committer | William M. Brack <wbrack@src.gnome.org> | 2004-07-03 09:53:08 +0000 |
commit | 63396bd87db785408eba67d4c5ccc2212b7d6a3a (patch) | |
tree | e81eb4a8363320f3602e4536555b99cd705512ed /doc/xslt.html | |
parent | a3a4c25d47e8fd9a817ad25c74c53e13a570cf36 (diff) | |
download | libxslt-63396bd87db785408eba67d4c5ccc2212b7d6a3a.tar.gz libxslt-63396bd87db785408eba67d4c5ccc2212b7d6a3a.tar.bz2 libxslt-63396bd87db785408eba67d4c5ccc2212b7d6a3a.zip |
corrected the URI for libxslt namespace, also a small enhancement of the
* doc/xslt.html, doc/extensions.html: corrected the URI for libxslt
namespace, also a small enhancement of the surrounding text on
extension functions. (bug 145250)
Diffstat (limited to 'doc/xslt.html')
-rw-r--r-- | doc/xslt.html | 70 |
1 files changed, 35 insertions, 35 deletions
diff --git a/doc/xslt.html b/doc/xslt.html index 22f7b801..2b2358bc 100644 --- a/doc/xslt.html +++ b/doc/xslt.html @@ -1833,25 +1833,25 @@ two <a href="http://www.w3.org/TR/xslt">ways to extend an XSLT engine</a>:</p> i.e. an URI used as the name for the extension's namespace (there is no need to have a resource there for this to work).</p> -<p>libxslt provides a few extensions itself, either in libxslt namespace -"http://xmlsoft.org/XSLT/" or in other namespace for well known extensions +<p>libxslt provides a few extensions itself, either in the libxslt namespace +"http://xmlsoft.org/XSLT/namespace" or in namespaces for other well known extensions provided by other XSLT processors like Saxon, Xalan or XT.</p> <h3><a name="Keep">Extension modules</a></h3> <p>Since extensions are bound to a namespace name, usually sets of extensions coming from a given source are using the same namespace name defining in -practice a group of extensions providing elements, functions or both. From +practice a group of extensions providing elements, functions or both. From the libxslt point of view those are considered as an "extension module", and most of the APIs work at a module point of view.</p> <p>Registration of new functions or elements are bound to the activation of -the module, this is currently done by declaring the namespace as an extension +the module. This is currently done by declaring the namespace as an extension by using the attribute <code>extension-element-prefixes</code> on the <code><a href="http://www.w3.org/TR/xslt">xsl:stylesheet</a></code> element.</p> -<p>And extension module is defined by 3 objects:</p> +<p>An extension module is defined by 3 objects:</p> <ul> <li>the namespace name associated</li> <li>an initialization function</li> @@ -1861,11 +1861,11 @@ element.</p> <h3><a name="Registerin">Registering a module</a></h3> <p>Currently a libxslt module has to be compiled within the application using -libxslt, there is no code to load dynamically shared libraries associated to +libxslt. There is no code to load dynamically shared libraries associated to a namespace (this may be added but is likely to become a portability nightmare).</p> -<p>So the current way to register a module is to link the code implementing +<p>The current way to register a module is to link the code implementing it with the application and to call a registration function:</p> <pre>int xsltRegisterExtModule(const xmlChar *URI, xsltExtInitFunction initFunc, @@ -1901,17 +1901,17 @@ typedef void *(*xsltExtInitFunction)(xsltTransformContextPtr ctxt, <p>There are 3 things to notice:</p> <ul> - <li>the function gets passed the namespace name URI as an argument, this - allow a single function to provide the initialization for multiple - logical modules</li> - <li>it also gets passed a transformation context, the initialization is + <li>The function gets passed the namespace name URI as an argument. This + allows a single function to provide the initialization for multiple + logical modules.</li> + <li>It also gets passed a transformation context. The initialization is done at run time before any processing occurs on the stylesheet but it - will be invoked separately each time for each transformation</li> - <li>it returns a pointer, this can be used to store module specific - informations which can be retrieved later when a function or an element - from the extension are used, an obvious example is a connection to a - database which should be kept and reused along the transformation. NULL - is a perfectly valid return, there is no way to indicate a failure at + will be invoked separately each time for each transformation.</li> + <li>It returns a pointer. This can be used to store module specific + information which can be retrieved later when a function or an element + from the extension is used. An obvious example is a connection to a + database which should be kept and reused along with the transformation. NULL + is a perfectly valid return; there is no way to indicate a failure at this level</li> </ul> @@ -1956,7 +1956,7 @@ typedef void (*xmlXPathEvalFunc)(xmlXPathParserContextPtr ctxt, href="internals.html#XPath1">XPath context</a>. However it is possible to find one from the other:</p> <ul> - <li>The function xsltXPathGetTransformContext provide this lookup facility: + <li>The function xsltXPathGetTransformContext provides this lookup facility: <pre>xsltTransformContextPtr xsltXPathGetTransformContext (xmlXPathParserContextPtr ctxt);</pre> @@ -1967,8 +1967,8 @@ find one from the other:</p> </ul> <p>The first thing an extension function may want to do is to check the -arguments passed on the stack, the <code>nargs</code> will precise how many -of them were provided on the XPath expression. The macros valuePop will +arguments passed on the stack, the <code>nargs</code> parameter will tell how many +of them were provided on the XPath expression. The macro valuePop will extract them from the XPath stack:</p> <pre>#include <libxml/xpath.h> #include <libxml/xpathInternals.h> @@ -1978,7 +1978,7 @@ xmlXPathObjectPtr obj = valuePop(ctxt); </pre> <p>Note that <code>ctxt</code> is the XPath context not the XSLT one. It is then possible to examine the content of the value. Check <a href="internals.html#Descriptio">the description of XPath objects</a> if -necessary. The following is a common sequcnce checking whether the argument +necessary. The following is a common sequence checking whether the argument passed is a string and converting it using the built-in XPath <code>string()</code> function if this is not the case:</p> <pre>if (obj->type != XPATH_STRING) { @@ -1997,7 +1997,7 @@ can be done using the xsltGetExtData:</p> <pre>void * xsltGetExtData(xsltTransformContextPtr ctxt, const xmlChar *URI);</pre> -<p>again the URI to be provided is the one used which was used when +<p>Again the URI to be provided is the one which was used when registering the module.</p> <p>Once the function finishes, don't forget to:</p> @@ -2010,7 +2010,7 @@ registering the module.</p> <h3><a name="Examples">Examples for extension functions</a></h3> -<p>The module libxslt/functions.c containsthe sources of the XSLT built-in +<p>The module libxslt/functions.c contains the sources of the XSLT built-in functions, including document(), key(), generate-id(), etc. as well as a full example module at the end. Here is the test function implementation for the libxslt:test function:</p> @@ -2057,7 +2057,7 @@ xsltExtFunctionTest(xmlXPathParserContextPtr ctxt, int nargs) except that the signature of an extension element implementation is different.</p> -<p>The registration is bound to a single transformation instance referred by +<p>The registration is bound to a single transformation instance referred to by ctxt, name is the UTF8 encoded name for the NCName of the element, and URI is the namespace name for the extension (no checking is done, a module could register elements for a different namespace, but it is not recommended).</p> @@ -2088,7 +2088,7 @@ href="internals.html#libxml">representation of XML nodes</a>. They are respectively <code>node</code> from the the input document being transformed by the stylesheet and <code>inst</code> the extension element in the stylesheet. The last argument is <code>comp</code> a pointer to a precompiled -representation of <code>inst</code> but usually for extension function this +representation of <code>inst</code> but usually for an extension function this value is <code>NULL</code> by default (it could be added and associated to the instruction in <code>inst->_private</code>).</p> @@ -2096,20 +2096,20 @@ the instruction in <code>inst->_private</code>).</p> element as in an extension function, including <code>xsltGetExtData()</code>.</p> -<p>The goal of extension element being usually to enrich the generated +<p>The goal of an extension element being usually to enrich the generated output, it is expected that they will grow the currently generated output -tree, this can be done by grabbing ctxt->insert which is the current +tree. This can be done by grabbing ctxt->insert which is the current libxml node being generated (Note this can also be the intermediate value tree being built for example to initialize a variable, the processing should be similar). The functions for libxml tree manipulation from <a href="http://xmlsoft.org/html/libxml-tree.html"><libxml/tree.h></a> can be employed to extend or modify the tree, but it is required to preserve the -insertion node and its ancestors since there is existing pointers to those +insertion node and its ancestors since there are existing pointers to those elements still in use in the XSLT template execution stack.</p> <h3><a name="Example">Example for extension elements</a></h3> -<p>The module libxslt/transform.c containsthe sources of the XSLT built-in +<p>The module libxslt/transform.c contains the sources of the XSLT built-in elements, including xsl:element, xsl:attribute, xsl:if, etc. There is a small but full example in functions.c providing the implementation for the libxslt:test element, it will output a comment in the result tree:</p> @@ -2158,7 +2158,7 @@ xsltExtElementTest(xsltTransformContextPtr ctxt, xmlNodePtr node, <h3><a name="shutdown">The shutdown of a module</a></h3> <p>When the XSLT processor ends a transformation, the shutdown function (if -it exists) of all the modules initialized are called.The +it exists) for each of the modules initialized is called. The xsltExtShutdownFunction type defines the interface for a shutdown function:</p> <pre>/** @@ -2173,17 +2173,17 @@ typedef void (*xsltExtShutdownFunction) (xsltTransformContextPtr ctxt, const xmlChar *URI, void *data);</pre> -<p>this is really similar to a module initialization function except a third +<p>This is really similar to a module initialization function except a third argument is passed, it's the value that was returned by the initialization -function. This allow to deallocate resources from the module for example +function. This allows the routine to deallocate resources from the module for example close the connection to the database to keep the same example.</p> <h3><a name="Future">Future work</a></h3> -<p>Well some of the pieces missing:</p> +<p>Well, some of the pieces missing:</p> <ul> - <li>a way to load shared libraries to instanciate new modules</li> - <li>a better detection of extension function usage and their registration + <li>a way to load shared libraries to instantiate new modules</li> + <li>a better detection of extension functions usage and their registration without having to use the extension prefix which ought to be reserved to element extensions.</li> <li>more examples</li> |