<?xml version="1.0" encoding="ascii"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>genshi.template.eval.Expression</title> <link rel="stylesheet" href="epydoc.css" type="text/css" /> <script type="text/javascript" src="epydoc.js"></script> </head> <body bgcolor="white" text="black" link="blue" vlink="#204080" alink="#204080"> <!-- ==================== NAVIGATION BAR ==================== --> <table class="navbar" border="0" width="100%" cellpadding="0" bgcolor="#a0c0ff" cellspacing="0"> <tr valign="middle"> <!-- Home link --> <th> <a href="genshi-module.html">Home</a> </th> <!-- Tree link --> <th> <a href="module-tree.html">Trees</a> </th> <!-- Index link --> <th> <a href="identifier-index.html">Indices</a> </th> <!-- Help link --> <th> <a href="help.html">Help</a> </th> <!-- Project homepage --> <th class="navbar" align="right" width="100%"> <table border="0" cellpadding="0" cellspacing="0"> <tr><th class="navbar" align="center" ><a class="navbar" target="_top" href="../index.html">Documentation Index</a></th> </tr></table></th> </tr> </table> <table width="100%" cellpadding="0" cellspacing="0"> <tr valign="top"> <td width="100%"> <span class="breadcrumbs"> <a href="genshi-module.html">Package genshi</a> :: <a href="genshi.template-module.html">Package template</a> :: <a href="genshi.template.eval-module.html">Module eval</a> :: Class Expression </span> </td> <td> <table cellpadding="0" cellspacing="0"> <!-- hide/show private --> </table> </td> </tr> </table> <!-- ==================== CLASS DESCRIPTION ==================== --> <h1 class="epydoc">Class Expression</h1><p class="nomargin-top"></p> <pre class="base-tree"> object --+ | <a href="genshi.template.eval.Code-class.html">Code</a> --+ | <strong class="uidshort">Expression</strong> </pre> <hr /> <p>Evaluates Python expressions used in templates.</p> <pre class="py-doctest"> <span class="py-prompt">>>> </span>data = dict(test=<span class="py-string">'Foo'</span>, <span class="py-builtin">items</span>=[1, 2, 3], dict={<span class="py-string">'some'</span>: <span class="py-string">'thing'</span>}) <span class="py-prompt">>>> </span>Expression(<span class="py-string">'test'</span>).evaluate(data) <span class="py-output">'Foo'</span></pre> <pre class="py-doctest"> <span class="py-prompt">>>> </span>Expression(<span class="py-string">'items[0]'</span>).evaluate(data) <span class="py-output">1</span> <span class="py-output"></span><span class="py-prompt">>>> </span>Expression(<span class="py-string">'items[-1]'</span>).evaluate(data) <span class="py-output">3</span> <span class="py-output"></span><span class="py-prompt">>>> </span>Expression(<span class="py-string">'dict["some"]'</span>).evaluate(data) <span class="py-output">'thing'</span></pre> <p>Similar to e.g. Javascript, expressions in templates can use the dot notation for attribute access to access items in mappings:</p> <pre class="py-doctest"> <span class="py-prompt">>>> </span>Expression(<span class="py-string">'dict.some'</span>).evaluate(data) <span class="py-output">'thing'</span></pre> <p>This also works the other way around: item access can be used to access any object attribute:</p> <pre class="py-doctest"> <span class="py-prompt">>>> </span><span class="py-keyword">class</span> <span class="py-defname">MyClass</span>(object): <span class="py-more">... </span> myattr = <span class="py-string">'Bar'</span> <span class="py-prompt">>>> </span>data = dict(mine=MyClass(), key=<span class="py-string">'myattr'</span>) <span class="py-prompt">>>> </span>Expression(<span class="py-string">'mine.myattr'</span>).evaluate(data) <span class="py-output">'Bar'</span> <span class="py-output"></span><span class="py-prompt">>>> </span>Expression(<span class="py-string">'mine["myattr"]'</span>).evaluate(data) <span class="py-output">'Bar'</span> <span class="py-output"></span><span class="py-prompt">>>> </span>Expression(<span class="py-string">'mine[key]'</span>).evaluate(data) <span class="py-output">'Bar'</span></pre> <p>All of the standard Python operators are available to template expressions. Built-in functions such as <tt class="rst-docutils literal">len()</tt> are also available in template expressions:</p> <pre class="py-doctest"> <span class="py-prompt">>>> </span>data = dict(<span class="py-builtin">items</span>=[1, 2, 3]) <span class="py-prompt">>>> </span>Expression(<span class="py-string">'len(items)'</span>).evaluate(data) <span class="py-output">3</span></pre> <!-- ==================== INSTANCE METHODS ==================== --> <a name="section-InstanceMethods"></a> <table class="summary" border="1" cellpadding="3" cellspacing="0" width="100%" bgcolor="white"> <tr bgcolor="#70b0f0" class="table-header"> <td align="left" colspan="2" class="table-header"> <span class="table-header">Instance Methods</span></td> </tr> <tr> <td width="15%" align="right" valign="top" class="summary"> <span class="summary-type"> </span> </td><td class="summary"> <table width="100%" cellpadding="0" cellspacing="0" border="0"> <tr> <td><span class="summary-sig"><a href="genshi.template.eval.Expression-class.html#evaluate" class="summary-sig-name">evaluate</a>(<span class="summary-sig-arg">self</span>, <span class="summary-sig-arg">data</span>)</span><br /> Evaluate the expression against the given data dictionary.</td> <td align="right" valign="top"> </td> </tr> </table> </td> </tr> <tr> <td colspan="2" class="summary"> <p class="indent-wrapped-lines"><b>Inherited from <code><a href="genshi.template.eval.Code-class.html">Code</a></code></b>: <code><a href="genshi.template.eval.Code-class.html#__eq__">__eq__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__getstate__">__getstate__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__hash__">__hash__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__init__">__init__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__ne__">__ne__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__repr__">__repr__</a></code>, <code><a href="genshi.template.eval.Code-class.html#__setstate__">__setstate__</a></code> </p> <p class="indent-wrapped-lines"><b>Inherited from <code>object</code></b>: <code>__delattr__</code>, <code>__format__</code>, <code>__getattribute__</code>, <code>__new__</code>, <code>__reduce__</code>, <code>__reduce_ex__</code>, <code>__setattr__</code>, <code>__sizeof__</code>, <code>__str__</code>, <code>__subclasshook__</code> </p> </td> </tr> </table> <!-- ==================== CLASS VARIABLES ==================== --> <a name="section-ClassVariables"></a> <table class="summary" border="1" cellpadding="3" cellspacing="0" width="100%" bgcolor="white"> <tr bgcolor="#70b0f0" class="table-header"> <td align="left" colspan="2" class="table-header"> <span class="table-header">Class Variables</span></td> </tr> <tr> <td width="15%" align="right" valign="top" class="summary"> <span class="summary-type"> </span> </td><td class="summary"> <a name="mode"></a><span class="summary-name">mode</span> = <code title="'eval'"><code class="variable-quote">'</code><code class="variable-string">eval</code><code class="variable-quote">'</code></code> </td> </tr> </table> <!-- ==================== PROPERTIES ==================== --> <a name="section-Properties"></a> <table class="summary" border="1" cellpadding="3" cellspacing="0" width="100%" bgcolor="white"> <tr bgcolor="#70b0f0" class="table-header"> <td align="left" colspan="2" class="table-header"> <span class="table-header">Properties</span></td> </tr> <tr> <td colspan="2" class="summary"> <p class="indent-wrapped-lines"><b>Inherited from <code><a href="genshi.template.eval.Code-class.html">Code</a></code></b>: <code><a href="genshi.template.eval.Code-class.html#ast">ast</a></code>, <code><a href="genshi.template.eval.Code-class.html#code">code</a></code>, <code><a href="genshi.template.eval.Code-class.html#source">source</a></code> </p> <p class="indent-wrapped-lines"><b>Inherited from <code>object</code></b>: <code>__class__</code> </p> </td> </tr> </table> <!-- ==================== METHOD DETAILS ==================== --> <a name="section-MethodDetails"></a> <table class="details" border="1" cellpadding="3" cellspacing="0" width="100%" bgcolor="white"> <tr bgcolor="#70b0f0" class="table-header"> <td align="left" colspan="2" class="table-header"> <span class="table-header">Method Details</span></td> </tr> </table> <a name="evaluate"></a> <div> <table class="details" border="1" cellpadding="3" cellspacing="0" width="100%" bgcolor="white"> <tr><td> <table width="100%" cellpadding="0" cellspacing="0" border="0"> <tr valign="top"><td> <h3 class="epydoc"><span class="sig"><span class="sig-name">evaluate</span>(<span class="sig-arg">self</span>, <span class="sig-arg">data</span>)</span> </h3> </td><td align="right" valign="top" > </td> </tr></table> Evaluate the expression against the given data dictionary. <dl class="fields"> <dt>Parameters:</dt> <dd><ul class="nomargin-top"> <li><strong class="pname"><code>data</code></strong> - a mapping containing the data to evaluate against</li> </ul></dd> <dt>Returns:</dt> <dd>the result of the evaluation</dd> </dl> </td></tr></table> </div> <br /> <!-- ==================== NAVIGATION BAR ==================== --> <table class="navbar" border="0" width="100%" cellpadding="0" bgcolor="#a0c0ff" cellspacing="0"> <tr valign="middle"> <!-- Home link --> <th> <a href="genshi-module.html">Home</a> </th> <!-- Tree link --> <th> <a href="module-tree.html">Trees</a> </th> <!-- Index link --> <th> <a href="identifier-index.html">Indices</a> </th> <!-- Help link --> <th> <a href="help.html">Help</a> </th> <!-- Project homepage --> <th class="navbar" align="right" width="100%"> <table border="0" cellpadding="0" cellspacing="0"> <tr><th class="navbar" align="center" ><a class="navbar" target="_top" href="../index.html">Documentation Index</a></th> </tr></table></th> </tr> </table> <table border="0" cellpadding="0" cellspacing="0" width="100%%"> <tr> <td align="left" class="footer"> Generated by Epydoc 3.0.1 on Sun Jan 27 18:17:20 2013 </td> <td align="right" class="footer"> <a target="mainFrame" href="http://epydoc.sourceforge.net" >http://epydoc.sourceforge.net</a> </td> </tr> </table> <script type="text/javascript"> <!-- // Private objects are initially displayed (because if // javascript is turned off then we want them to be // visible); but by default, we want to hide them. So hide // them unless we have a cookie that says to show them. checkCookie(); // --> </script> </body> </html>