diff options
Diffstat (limited to 'docs/manual/xpath.html')
| -rw-r--r-- | docs/manual/xpath.html | 44 |
1 files changed, 19 insertions, 25 deletions
diff --git a/docs/manual/xpath.html b/docs/manual/xpath.html index 513bb90..731a969 100644 --- a/docs/manual/xpath.html +++ b/docs/manual/xpath.html @@ -54,9 +54,6 @@ at tizag.com</a>, and <a href="http://www.w3.org/TR/xpath/" target="_top">the XPath 1.0 specification</a>. </p> -<p> - $$ - </p> <div class="note"><table border="0" summary="Note"> <tr> <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> @@ -123,11 +120,9 @@ You can also create XPath nodes with one of tree constructors: the default constructor, the constructor that takes node argument, and the constructor that takes attribute and node arguments (in which case the attribute must - belong to the attribute list of the node). The constructor from <code class="computeroutput"><span class="identifier">xml_node</span></code> is implicit, so you can usually - pass <code class="computeroutput"><span class="identifier">xml_node</span></code> to functions - that expect <code class="computeroutput"><span class="identifier">xpath_node</span></code>. Apart - from that you usually don't need to create your own XPath node objects, since - they are returned to you via selection functions. + belong to the attribute list of the node). However, usually you don't need + to create your own XPath node objects, since they are returned to you via + selection functions. </p> <a name="xpath_node_set"></a><p> XPath expressions operate not on single nodes, but instead on node sets. @@ -314,21 +309,20 @@ <a name="xpath_query::evaluate_boolean"></a><a name="xpath_query::evaluate_number"></a><a name="xpath_query::evaluate_string"></a><a name="xpath_query::evaluate_node_set"></a><p> You can evaluate the query using one of the following functions: </p> -<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_boolean</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xpath_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> -<span class="keyword">double</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_number</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xpath_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> -<span class="identifier">string_t</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_string</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xpath_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> -<span class="identifier">xpath_node_set</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_node_set</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xpath_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_boolean</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> +<span class="keyword">double</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_number</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> +<span class="identifier">string_t</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_string</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> +<span class="identifier">xpath_node_set</span> <span class="identifier">xpath_query</span><span class="special">::</span><span class="identifier">evaluate_node_set</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">xml_node</span><span class="special">&</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> </pre> <p> - $$ exception, evaluate_string nostl All functions take the context node as - an argument, compute the expression and return the result, converted to the - requested type. By XPath specification, value of any type can be converted - to boolean, number or string value, but no type other than node set can be - converted to node set. Because of this, <code class="computeroutput"><span class="identifier">evaluate_boolean</span></code>, - <code class="computeroutput"><span class="identifier">evaluate_number</span></code> and <code class="computeroutput"><span class="identifier">evaluate_string</span></code> always return a result, - but <code class="computeroutput"><span class="identifier">evaluate_node_set</span></code> throws - an <code class="computeroutput"><span class="identifier">xpath_exception</span></code> if the - return type is not node set. + All functions take the context node as an argument, compute the expression + and return the result, converted to the requested type. By XPath specification, + value of any type can be converted to boolean, number or string value, but + no type other than node set can be converted to node set. Because of this, + <code class="computeroutput"><span class="identifier">evaluate_boolean</span></code>, <code class="computeroutput"><span class="identifier">evaluate_number</span></code> and <code class="computeroutput"><span class="identifier">evaluate_string</span></code> + always return a result, but <code class="computeroutput"><span class="identifier">evaluate_node_set</span></code> + throws an <code class="computeroutput"><span class="identifier">xpath_exception</span></code> + if the return type is not node set. </p> <div class="note"><table border="0" summary="Note"> <tr> @@ -376,7 +370,7 @@ <a name="manual.xpath.errors"></a><a class="link" href="xpath.html#manual.xpath.errors" title="Error handling"> Error handling</a> </h3></div></div></div> <a name="xpath_exception"></a><a name="xpath_exception::what"></a><p> - $$ As of version 0.9, all XPath errors result in thrown exceptions. The errors + As of version 0.9, all XPath errors result in thrown exceptions. The errors can arise during expression compilation or node set evaluation. In both cases, an <code class="computeroutput"><span class="identifier">xpath_exception</span></code> object is thrown. This is an exception object that implements <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception</span></code> @@ -385,8 +379,8 @@ <pre class="programlisting"><span class="keyword">virtual</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">xpath_exception</span><span class="special">::</span><span class="identifier">what</span><span class="special">()</span> <span class="keyword">const</span> <span class="keyword">throw</span><span class="special">();</span> </pre> <p> - $$ This function returns the error message. Currently it is impossible to - get the exact place where query compilation failed. This functionality, along + This function returns the error message. Currently it is impossible to get + the exact place where query compilation failed. This functionality, along with optional error handling without exceptions, will be available in version 1.0. </p> @@ -470,7 +464,7 @@ </li> </ul></div> <p> - $$ Some of these incompatibilities will be fixed in version 1.0. + Some of these incompatibilities will be fixed in version 1.0. </p> </div> </div> |