| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671 |
- <html xmlns="http://www.w3.org/1999/xhtml">
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
- <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon">
- <head>
- <title>
-
- Inheritance
- —
- Mako 0.7.2 Documentation
- </title>
- <link rel="stylesheet" href="_static/pygments.css" type="text/css" />
- <link rel="stylesheet" href="_static/docs.css" type="text/css" />
- <script type="text/javascript">
- var DOCUMENTATION_OPTIONS = {
- URL_ROOT: '#',
- VERSION: '0.7.2',
- COLLAPSE_MODINDEX: false,
- FILE_SUFFIX: '.html'
- };
- </script>
- <script type="text/javascript" src="_static/jquery.js"></script>
- <script type="text/javascript" src="_static/underscore.js"></script>
- <script type="text/javascript" src="_static/doctools.js"></script>
- <link rel="index" title="Index" href="genindex.html" />
- <link rel="search" title="Search" href="search.html" />
- <link rel="top" title="Mako 0.7.2 Documentation" href="index.html" />
- <link rel="next" title="Filtering and Buffering" href="filtering.html" />
- <link rel="prev" title="Namespaces" href="namespaces.html" />
- <link rel="stylesheet" href="_static/site.css"></link>
- </head>
- <body>
- <div id="wrap">
- <div class="rightbar">
- <div class="slogan">
- Hyperfast and lightweight templating for the Python platform.
- </div>
- </div>
- <a href="http://www.makotemplates.org/"><img src="_static/makoLogo.png" /></a>
- <hr/>
-
- <div id="docs-container">
- <div id="docs-header">
- <h1>Mako 0.7.2 Documentation</h1>
- <div id="docs-search">
- Search:
- <form class="search" action="search.html" method="get">
- <input type="text" name="q" size="18" /> <input type="submit" value="Search" />
- <input type="hidden" name="check_keywords" value="yes" />
- <input type="hidden" name="area" value="default" />
- </form>
- </div>
- <div id="docs-version-header">
- Release: <span class="version-num">0.7.2</span>
- </div>
- </div>
- <div id="docs-top-navigation">
- <div id="docs-top-page-control" class="docs-navigation-links">
- <ul>
- <li>Prev:
- <a href="namespaces.html" title="previous chapter">Namespaces</a>
- </li>
- <li>Next:
- <a href="filtering.html" title="next chapter">Filtering and Buffering</a>
- </li>
- <li>
- <a href="index.html">Table of Contents</a> |
- <a href="genindex.html">Index</a>
- | <a href="_sources/inheritance.txt">view source
- </li>
- </ul>
- </div>
- <div id="docs-navigation-banner">
- <a href="index.html">Mako 0.7.2 Documentation</a>
- »
- Inheritance
-
- <h2>
-
- Inheritance
-
- </h2>
- </div>
- </div>
- <div id="docs-body-container">
- <div id="docs-sidebar">
- <h3><a href="index.html">Table of Contents</a></h3>
- <ul>
- <li><a class="reference internal" href="#">Inheritance</a><ul>
- <li><a class="reference internal" href="#nesting-blocks">Nesting Blocks</a></li>
- <li><a class="reference internal" href="#rendering-a-named-block-multiple-times">Rendering a Named Block Multiple Times</a></li>
- <li><a class="reference internal" href="#but-what-about-defs">But what about Defs?</a></li>
- <li><a class="reference internal" href="#using-the-next-namespace-to-produce-content-wrapping">Using the <tt class="docutils literal"><span class="pre">next</span></tt> Namespace to Produce Content Wrapping</a></li>
- <li><a class="reference internal" href="#using-the-parent-namespace-to-augment-defs">Using the <tt class="docutils literal"><span class="pre">parent</span></tt> Namespace to Augment Defs</a></li>
- <li><a class="reference internal" href="#inheritable-attributes">Inheritable Attributes</a></li>
- </ul>
- </li>
- </ul>
- <h4>Previous Topic</h4>
- <p>
- <a href="namespaces.html" title="previous chapter">Namespaces</a>
- </p>
- <h4>Next Topic</h4>
- <p>
- <a href="filtering.html" title="next chapter">Filtering and Buffering</a>
- </p>
- <h4>Quick Search</h4>
- <p>
- <form class="search" action="search.html" method="get">
- <input type="text" name="q" size="18" /> <input type="submit" value="Search" />
- <input type="hidden" name="check_keywords" value="yes" />
- <input type="hidden" name="area" value="default" />
- </form>
- </p>
- </div>
- <div id="docs-body" class="withsidebar" >
-
- <div class="section" id="inheritance">
- <span id="inheritance-toplevel"></span><h1>Inheritance<a class="headerlink" href="#inheritance" title="Permalink to this headline">¶</a></h1>
- <div class="admonition note">
- <p class="first admonition-title">Note</p>
- <p class="last">Most of the inheritance examples here take advantage of a feature that’s
- new in Mako as of version 0.4.1 called the “block”. This tag is very similar to
- the “def” tag but is more streamlined for usage with inheritance. Note that
- all of the examples here which use blocks can also use defs instead. Contrasting
- usages will be illustrated.</p>
- </div>
- <p>Using template inheritance, two or more templates can organize
- themselves into an <strong>inheritance chain</strong>, where content and
- functions from all involved templates can be intermixed. The
- general paradigm of template inheritance is this: if a template
- <tt class="docutils literal"><span class="pre">A</span></tt> inherits from template <tt class="docutils literal"><span class="pre">B</span></tt>, then template <tt class="docutils literal"><span class="pre">A</span></tt> agrees
- to send the executional control to template <tt class="docutils literal"><span class="pre">B</span></tt> at runtime
- (<tt class="docutils literal"><span class="pre">A</span></tt> is called the <strong>inheriting</strong> template). Template <tt class="docutils literal"><span class="pre">B</span></tt>,
- the <strong>inherited</strong> template, then makes decisions as to what
- resources from <tt class="docutils literal"><span class="pre">A</span></tt> shall be executed.</p>
- <p>In practice, it looks like this. Here’s a hypothetical inheriting
- template, <tt class="docutils literal"><span class="pre">index.html</span></tt>:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"base.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is some header content</span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x">this is the body content.</span>
- </pre></div>
- </div>
- <p>And <tt class="docutils literal"><span class="pre">base.html</span></tt>, the inherited template:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## base.html</span><span class="x"></span>
- <span class="x"><html></span>
- <span class="x"> <body></span>
- <span class="x"> <div class="header"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> <div class="footer"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"footer"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is the footer</span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </body></span>
- <span class="x"></html></span>
- </pre></div>
- </div>
- <p>Here is a breakdown of the execution:</p>
- <ol class="arabic">
- <li><p class="first">When <tt class="docutils literal"><span class="pre">index.html</span></tt> is rendered, control immediately passes to
- <tt class="docutils literal"><span class="pre">base.html</span></tt>.</p>
- </li>
- <li><p class="first"><tt class="docutils literal"><span class="pre">base.html</span></tt> then renders the top part of an HTML document,
- then invokes the <tt class="docutils literal"><span class="pre"><%block</span> <span class="pre">name="header"></span></tt> block. It invokes the
- underlying <tt class="docutils literal"><span class="pre">header()</span></tt> function off of a built-in namespace
- called <tt class="docutils literal"><span class="pre">self</span></tt> (this namespace was first introduced in the
- <a class="reference internal" href="namespaces.html"><em>Namespaces chapter</em></a> in <a class="reference internal" href="namespaces.html#namespace-self"><em>self</em></a>). Since
- <tt class="docutils literal"><span class="pre">index.html</span></tt> is the topmost template and also defines a block
- called <tt class="docutils literal"><span class="pre">header</span></tt>, it’s this <tt class="docutils literal"><span class="pre">header</span></tt> block that ultimately gets
- executed – instead of the one that’s present in <tt class="docutils literal"><span class="pre">base.html</span></tt>.</p>
- </li>
- <li><p class="first">Control comes back to <tt class="docutils literal"><span class="pre">base.html</span></tt>. Some more HTML is
- rendered.</p>
- </li>
- <li><p class="first"><tt class="docutils literal"><span class="pre">base.html</span></tt> executes <tt class="docutils literal"><span class="pre">self.body()</span></tt>. The <tt class="docutils literal"><span class="pre">body()</span></tt>
- function on all template-based namespaces refers to the main
- body of the template, therefore the main body of
- <tt class="docutils literal"><span class="pre">index.html</span></tt> is rendered.</p>
- </li>
- <li><p class="first">When <tt class="docutils literal"><span class="pre"><%block</span> <span class="pre">name="header"></span></tt> is encountered in <tt class="docutils literal"><span class="pre">index.html</span></tt>
- during the <tt class="docutils literal"><span class="pre">self.body()</span></tt> call, a conditional is checked – does the
- current inherited template, i.e. <tt class="docutils literal"><span class="pre">base.html</span></tt>, also define this block? If yes,
- the <tt class="docutils literal"><span class="pre"><%block></span></tt> is <strong>not</strong> executed here – the inheritance
- mechanism knows that the parent template is responsible for rendering
- this block (and in fact it already has). In other words a block
- only renders in its <em>basemost scope</em>.</p>
- </li>
- <li><p class="first">Control comes back to <tt class="docutils literal"><span class="pre">base.html</span></tt>. More HTML is rendered,
- then the <tt class="docutils literal"><span class="pre"><%block</span> <span class="pre">name="footer"></span></tt> expression is invoked.</p>
- </li>
- <li><p class="first">The <tt class="docutils literal"><span class="pre">footer</span></tt> block is only defined in <tt class="docutils literal"><span class="pre">base.html</span></tt>, so being
- the topmost definition of <tt class="docutils literal"><span class="pre">footer</span></tt>, it’s the one that
- executes. If <tt class="docutils literal"><span class="pre">index.html</span></tt> also specified <tt class="docutils literal"><span class="pre">footer</span></tt>, then
- its version would <strong>override</strong> that of the base.</p>
- </li>
- <li><p class="first"><tt class="docutils literal"><span class="pre">base.html</span></tt> finishes up rendering its HTML and the template
- is complete, producing:</p>
- <div class="highlight-html"><div class="highlight"><pre><span class="nt"><html></span>
- <span class="nt"><body></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"header"</span><span class="nt">></span>
- this is some header content
- <span class="nt"></div></span>
- this is the body content.
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"footer"</span><span class="nt">></span>
- this is the footer
- <span class="nt"></div></span>
- <span class="nt"></body></span>
- <span class="nt"></html></span>
- </pre></div>
- </div>
- </li>
- </ol>
- <p>...and that is template inheritance in a nutshell. The main idea
- is that the methods that you call upon <tt class="docutils literal"><span class="pre">self</span></tt> always
- correspond to the topmost definition of that method. Very much
- the way <tt class="docutils literal"><span class="pre">self</span></tt> works in a Python class, even though Mako is
- not actually using Python class inheritance to implement this
- functionality. (Mako doesn’t take the “inheritance” metaphor too
- seriously; while useful to setup some commonly recognized
- semantics, a textual template is not very much like an
- object-oriented class construct in practice).</p>
- <div class="section" id="nesting-blocks">
- <h2>Nesting Blocks<a class="headerlink" href="#nesting-blocks" title="Permalink to this headline">¶</a></h2>
- <p>The named blocks defined in an inherited template can also be nested within
- other blocks. The name given to each block is globally accessible via any inheriting
- template. We can add a new block <tt class="docutils literal"><span class="pre">title</span></tt> to our <tt class="docutils literal"><span class="pre">header</span></tt> block:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## base.html</span><span class="x"></span>
- <span class="x"><html></span>
- <span class="x"> <body></span>
- <span class="x"> <div class="header"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <h2></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"title"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"> </h2></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> <div class="footer"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"footer"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is the footer</span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </body></span>
- <span class="x"></html></span>
- </pre></div>
- </div>
- <p>The inheriting template can name either or both of <tt class="docutils literal"><span class="pre">header</span></tt> and <tt class="docutils literal"><span class="pre">title</span></tt>, separately
- or nested themselves:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"base.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is some header content</span>
- <span class="x"> </span><span class="cp">${</span><span class="n">parent</span><span class="o">.</span><span class="n">header</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"title"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is the title</span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x">this is the body content.</span>
- </pre></div>
- </div>
- <p>Note when we overrode <tt class="docutils literal"><span class="pre">header</span></tt>, we added an extra call <tt class="docutils literal"><span class="pre">${parent.header()}</span></tt> in order to invoke
- the parent’s <tt class="docutils literal"><span class="pre">header</span></tt> block in addition to our own. That’s described in more detail below,
- in <a class="reference internal" href="#parent-namespace"><em>Using the parent Namespace to Augment Defs</em></a>.</p>
- </div>
- <div class="section" id="rendering-a-named-block-multiple-times">
- <h2>Rendering a Named Block Multiple Times<a class="headerlink" href="#rendering-a-named-block-multiple-times" title="Permalink to this headline">¶</a></h2>
- <p>Recall from the section <a class="reference internal" href="defs.html#blocks"><em>Using Blocks</em></a> that a named block is just like a <tt class="docutils literal"><span class="pre"><%def></span></tt>,
- with some different usage rules. We can call one of our named sections distinctly, for example
- a section that is used more than once, such as the title of a page:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="x"><html></span>
- <span class="x"> <head></span>
- <span class="x"> <title></span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">title</span><span class="p">()</span><span class="cp">}</span><span class="x"></title></span>
- <span class="x"> </head></span>
- <span class="x"> <body></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <h2></span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"title"</span><span class="cp">/></span><span class="x"></h2></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </body></span>
- <span class="x"></html></span>
- </pre></div>
- </div>
- <p>Where above an inheriting template can define <tt class="docutils literal"><span class="pre"><%block</span> <span class="pre">name="title"></span></tt> just once, and it will be
- used in the base template both in the <tt class="docutils literal"><span class="pre"><title></span></tt> section as well as the <tt class="docutils literal"><span class="pre"><h2></span></tt>.</p>
- </div>
- <div class="section" id="but-what-about-defs">
- <h2>But what about Defs?<a class="headerlink" href="#but-what-about-defs" title="Permalink to this headline">¶</a></h2>
- <p>The previous example used the <tt class="docutils literal"><span class="pre"><%block></span></tt> tag to produce areas of content
- to be overridden. Before Mako 0.4.1, there wasn’t any such tag – instead
- there was only the <tt class="docutils literal"><span class="pre"><%def></span></tt> tag. As it turns out, named blocks and defs are
- largely interchangeable. The def simply doesn’t call itself automatically,
- and has more open-ended naming and scoping rules that are more flexible and similar
- to Python itself, but less suited towards layout. The first example from
- this chapter using defs would look like:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"base.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"header()"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is some header content</span>
- <span class="cp"></%</span><span class="nb">def</span><span class="cp">></span><span class="x"></span>
- <span class="x">this is the body content.</span>
- </pre></div>
- </div>
- <p>And <tt class="docutils literal"><span class="pre">base.html</span></tt>, the inherited template:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## base.html</span><span class="x"></span>
- <span class="x"><html></span>
- <span class="x"> <body></span>
- <span class="x"> <div class="header"></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">header</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> <div class="footer"></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">footer</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </body></span>
- <span class="x"></html></span>
- <span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"header()"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"footer()"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is the footer</span>
- <span class="cp"></%</span><span class="nb">def</span><span class="cp">></span><span class="x"></span>
- </pre></div>
- </div>
- <p>Above, we illustrate that defs differ from blocks in that their definition
- and invocation are defined in two separate places, instead of at once. You can <em>almost</em> do exactly what a
- block does if you put the two together:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="x"><div class="header"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"header()"</span><span class="cp">></%</span><span class="nb">def</span><span class="cp">>${</span><span class="bp">self</span><span class="o">.</span><span class="n">header</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"></div></span>
- </pre></div>
- </div>
- <p>The <tt class="docutils literal"><span class="pre"><%block></span></tt> is obviously more streamlined than the <tt class="docutils literal"><span class="pre"><%def></span></tt> for this kind
- of usage. In addition,
- the above “inline” approach with <tt class="docutils literal"><span class="pre"><%def></span></tt> does not work with nesting:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="x"><head></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"header()"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <title></span>
- <span class="x"> ## this won't work !</span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"title()"</span><span class="cp">></span><span class="x">default title</span><span class="cp"></%</span><span class="nb">def</span><span class="cp">>${</span><span class="bp">self</span><span class="o">.</span><span class="n">title</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </title></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">def</span><span class="cp">>${</span><span class="bp">self</span><span class="o">.</span><span class="n">header</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"></head></span>
- </pre></div>
- </div>
- <p>Where above, the <tt class="docutils literal"><span class="pre">title()</span></tt> def, because it’s a def within a def, is not part of the
- template’s exported namespace and will not be part of <tt class="docutils literal"><span class="pre">self</span></tt>. If the inherited template
- did define its own <tt class="docutils literal"><span class="pre">title</span></tt> def at the top level, it would be called, but the “default title”
- above is not present at all on <tt class="docutils literal"><span class="pre">self</span></tt> no matter what. For this to work as expected
- you’d instead need to say:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="x"><head></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"header()"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <title></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">title</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </title></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">def</span><span class="cp">>${</span><span class="bp">self</span><span class="o">.</span><span class="n">header</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">def</span> <span class="na">name=</span><span class="s">"title()"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"></head></span>
- </pre></div>
- </div>
- <p>That is, <tt class="docutils literal"><span class="pre">title</span></tt> is defined outside of any other defs so that it is in the <tt class="docutils literal"><span class="pre">self</span></tt> namespace.
- It works, but the definition needs to be potentially far away from the point of render.</p>
- <p>A named block is always placed in the <tt class="docutils literal"><span class="pre">self</span></tt> namespace, regardless of nesting,
- so this restriction is lifted:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## base.html</span><span class="x"></span>
- <span class="x"><head></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <title></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"title"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"> </title></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"></head></span>
- </pre></div>
- </div>
- <p>The above template defines <tt class="docutils literal"><span class="pre">title</span></tt> inside of <tt class="docutils literal"><span class="pre">header</span></tt>, and an inheriting template can define
- one or both in <strong>any</strong> configuration, nested inside each other or not, in order for them to be used:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"base.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"title"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> the title</span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> the header</span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- </pre></div>
- </div>
- <p>So while the <tt class="docutils literal"><span class="pre"><%block></span></tt> tag lifts the restriction of nested blocks not being available externally,
- in order to achieve this it <em>adds</em> the restriction that all block names in a single template need
- to be globally unique within the template, and additionally that a <tt class="docutils literal"><span class="pre"><%block></span></tt> can’t be defined
- inside of a <tt class="docutils literal"><span class="pre"><%def></span></tt>. It’s a more restricted tag suited towards a more specific use case than <tt class="docutils literal"><span class="pre"><%def></span></tt>.</p>
- </div>
- <div class="section" id="using-the-next-namespace-to-produce-content-wrapping">
- <h2>Using the <tt class="docutils literal"><span class="pre">next</span></tt> Namespace to Produce Content Wrapping<a class="headerlink" href="#using-the-next-namespace-to-produce-content-wrapping" title="Permalink to this headline">¶</a></h2>
- <p>Sometimes you have an inheritance chain that spans more than two
- templates. Or maybe you don’t, but you’d like to build your
- system such that extra inherited templates can be inserted in
- the middle of a chain where they would be smoothly integrated.
- If each template wants to define its layout just within its main
- body, you can’t just call <tt class="docutils literal"><span class="pre">self.body()</span></tt> to get at the
- inheriting template’s body, since that is only the topmost body.
- To get at the body of the <em>next</em> template, you call upon the
- namespace <tt class="docutils literal"><span class="pre">next</span></tt>, which is the namespace of the template
- <strong>immediately following</strong> the current template.</p>
- <p>Lets change the line in <tt class="docutils literal"><span class="pre">base.html</span></tt> which calls upon
- <tt class="docutils literal"><span class="pre">self.body()</span></tt> to instead call upon <tt class="docutils literal"><span class="pre">next.body()</span></tt>:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## base.html</span><span class="x"></span>
- <span class="x"><html></span>
- <span class="x"> <body></span>
- <span class="x"> <div class="header"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </span><span class="cp">${</span><span class="nb">next</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> <div class="footer"></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"footer"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is the footer</span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"> </div></span>
- <span class="x"> </body></span>
- <span class="x"></html></span>
- </pre></div>
- </div>
- <p>Lets also add an intermediate template called <tt class="docutils literal"><span class="pre">layout.html</span></tt>,
- which inherits from <tt class="docutils literal"><span class="pre">base.html</span></tt>:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## layout.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"base.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="x"><ul></span>
- <span class="x"> </span><span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"toolbar"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> <li>selection 1</li></span>
- <span class="x"> <li>selection 2</li></span>
- <span class="x"> <li>selection 3</li></span>
- <span class="x"> </span><span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x"></ul></span>
- <span class="x"><div class="mainlayout"></span>
- <span class="x"> </span><span class="cp">${</span><span class="nb">next</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"></div></span>
- </pre></div>
- </div>
- <p>And finally change <tt class="docutils literal"><span class="pre">index.html</span></tt> to inherit from
- <tt class="docutils literal"><span class="pre">layout.html</span></tt> instead:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"layout.html"</span><span class="cp">/></span>
- <span class="cp">## .. rest of template</span><span class="x"></span>
- </pre></div>
- </div>
- <p>In this setup, each call to <tt class="docutils literal"><span class="pre">next.body()</span></tt> will render the body
- of the next template in the inheritance chain (which can be
- written as <tt class="docutils literal"><span class="pre">base.html</span> <span class="pre">-></span> <span class="pre">layout.html</span> <span class="pre">-></span> <span class="pre">index.html</span></tt>). Control
- is still first passed to the bottommost template <tt class="docutils literal"><span class="pre">base.html</span></tt>,
- and <tt class="docutils literal"><span class="pre">self</span></tt> still references the topmost definition of any
- particular def.</p>
- <p>The output we get would be:</p>
- <div class="highlight-html"><div class="highlight"><pre><span class="nt"><html></span>
- <span class="nt"><body></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"header"</span><span class="nt">></span>
- this is some header content
- <span class="nt"></div></span>
- <span class="nt"><ul></span>
- <span class="nt"><li></span>selection 1<span class="nt"></li></span>
- <span class="nt"><li></span>selection 2<span class="nt"></li></span>
- <span class="nt"><li></span>selection 3<span class="nt"></li></span>
- <span class="nt"></ul></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"mainlayout"</span><span class="nt">></span>
- this is the body content.
- <span class="nt"></div></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"footer"</span><span class="nt">></span>
- this is the footer
- <span class="nt"></div></span>
- <span class="nt"></body></span>
- <span class="nt"></html></span>
- </pre></div>
- </div>
- <p>So above, we have the <tt class="docutils literal"><span class="pre"><html></span></tt>, <tt class="docutils literal"><span class="pre"><body></span></tt> and
- <tt class="docutils literal"><span class="pre">header</span></tt>/<tt class="docutils literal"><span class="pre">footer</span></tt> layout of <tt class="docutils literal"><span class="pre">base.html</span></tt>, we have the
- <tt class="docutils literal"><span class="pre"><ul></span></tt> and <tt class="docutils literal"><span class="pre">mainlayout</span></tt> section of <tt class="docutils literal"><span class="pre">layout.html</span></tt>, and the
- main body of <tt class="docutils literal"><span class="pre">index.html</span></tt> as well as its overridden <tt class="docutils literal"><span class="pre">header</span></tt>
- def. The <tt class="docutils literal"><span class="pre">layout.html</span></tt> template is inserted into the middle of
- the chain without <tt class="docutils literal"><span class="pre">base.html</span></tt> having to change anything.
- Without the <tt class="docutils literal"><span class="pre">next</span></tt> namespace, only the main body of
- <tt class="docutils literal"><span class="pre">index.html</span></tt> could be used; there would be no way to call
- <tt class="docutils literal"><span class="pre">layout.html</span></tt>‘s body content.</p>
- </div>
- <div class="section" id="using-the-parent-namespace-to-augment-defs">
- <span id="parent-namespace"></span><h2>Using the <tt class="docutils literal"><span class="pre">parent</span></tt> Namespace to Augment Defs<a class="headerlink" href="#using-the-parent-namespace-to-augment-defs" title="Permalink to this headline">¶</a></h2>
- <p>Lets now look at the other inheritance-specific namespace, the
- opposite of <tt class="docutils literal"><span class="pre">next</span></tt> called <tt class="docutils literal"><span class="pre">parent</span></tt>. <tt class="docutils literal"><span class="pre">parent</span></tt> is the
- namespace of the template <strong>immediately preceding</strong> the current
- template. What’s useful about this namespace is that
- defs or blocks can call upon their overridden versions.
- This is not as hard as it sounds and
- is very much like using the <tt class="docutils literal"><span class="pre">super</span></tt> keyword in Python. Lets
- modify <tt class="docutils literal"><span class="pre">index.html</span></tt> to augment the list of selections provided
- by the <tt class="docutils literal"><span class="pre">toolbar</span></tt> function in <tt class="docutils literal"><span class="pre">layout.html</span></tt>:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp">## index.html</span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"layout.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"header"</span><span class="cp">></span><span class="x"></span>
- <span class="x"> this is some header content</span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">block</span> <span class="na">name=</span><span class="s">"toolbar"</span><span class="cp">></span>
- <span class="cp">## call the parent's toolbar first</span><span class="x"></span>
- <span class="x"> </span><span class="cp">${</span><span class="n">parent</span><span class="o">.</span><span class="n">toolbar</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"> <li>selection 4</li></span>
- <span class="x"> <li>selection 5</li></span>
- <span class="cp"></%</span><span class="nb">block</span><span class="cp">></span><span class="x"></span>
- <span class="x">this is the body content.</span>
- </pre></div>
- </div>
- <p>Above, we implemented a <tt class="docutils literal"><span class="pre">toolbar()</span></tt> function, which is meant
- to override the definition of <tt class="docutils literal"><span class="pre">toolbar</span></tt> within the inherited
- template <tt class="docutils literal"><span class="pre">layout.html</span></tt>. However, since we want the content
- from that of <tt class="docutils literal"><span class="pre">layout.html</span></tt> as well, we call it via the
- <tt class="docutils literal"><span class="pre">parent</span></tt> namespace whenever we want it’s content, in this case
- before we add our own selections. So the output for the whole
- thing is now:</p>
- <div class="highlight-html"><div class="highlight"><pre><span class="nt"><html></span>
- <span class="nt"><body></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"header"</span><span class="nt">></span>
- this is some header content
- <span class="nt"></div></span>
- <span class="nt"><ul></span>
- <span class="nt"><li></span>selection 1<span class="nt"></li></span>
- <span class="nt"><li></span>selection 2<span class="nt"></li></span>
- <span class="nt"><li></span>selection 3<span class="nt"></li></span>
- <span class="nt"><li></span>selection 4<span class="nt"></li></span>
- <span class="nt"><li></span>selection 5<span class="nt"></li></span>
- <span class="nt"></ul></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"mainlayout"</span><span class="nt">></span>
- this is the body content.
- <span class="nt"></div></span>
- <span class="nt"><div</span> <span class="na">class=</span><span class="s">"footer"</span><span class="nt">></span>
- this is the footer
- <span class="nt"></div></span>
- <span class="nt"></body></span>
- <span class="nt"></html></span>
- </pre></div>
- </div>
- <p>and you’re now a template inheritance ninja!</p>
- </div>
- <div class="section" id="inheritable-attributes">
- <h2>Inheritable Attributes<a class="headerlink" href="#inheritable-attributes" title="Permalink to this headline">¶</a></h2>
- <p>The <a class="reference internal" href="namespaces.html#mako.runtime.Namespace.attr" title="mako.runtime.Namespace.attr"><tt class="xref py py-attr docutils literal"><span class="pre">attr</span></tt></a> accessor of the <a class="reference internal" href="namespaces.html#mako.runtime.Namespace" title="mako.runtime.Namespace"><tt class="xref py py-class docutils literal"><span class="pre">Namespace</span></tt></a> object
- allows access to module level variables declared in a template. By accessing
- <tt class="docutils literal"><span class="pre">self.attr</span></tt>, you can access regular attributes from the
- inheritance chain as declared in <tt class="docutils literal"><span class="pre"><%!</span> <span class="pre">%></span></tt> sections. Such as:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp"><%!</span>
- <span class="n">class_</span> <span class="o">=</span> <span class="s">"grey"</span>
- <span class="cp">%></span><span class="x"></span>
- <span class="x"><div class="</span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">attr</span><span class="o">.</span><span class="n">class_</span><span class="cp">}</span><span class="x">"></span>
- <span class="x"> </span><span class="cp">${</span><span class="bp">self</span><span class="o">.</span><span class="n">body</span><span class="p">()</span><span class="cp">}</span><span class="x"></span>
- <span class="x"></div></span>
- </pre></div>
- </div>
- <p>If an inheriting template overrides <tt class="docutils literal"><span class="pre">class_</span></tt> to be
- <tt class="docutils literal"><span class="pre">"white"</span></tt>, as in:</p>
- <div class="highlight-mako"><div class="highlight"><pre><span class="cp"><%!</span>
- <span class="n">class_</span> <span class="o">=</span> <span class="s">"white"</span>
- <span class="cp">%></span><span class="x"></span>
- <span class="cp"><%</span><span class="nb">inherit</span> <span class="na">file=</span><span class="s">"parent.html"</span><span class="cp">/></span><span class="x"></span>
- <span class="x">This is the body</span>
- </pre></div>
- </div>
- <p>you’ll get output like:</p>
- <div class="highlight-html"><div class="highlight"><pre><span class="nt"><div</span> <span class="na">class=</span><span class="s">"white"</span><span class="nt">></span>
- This is the body
- <span class="nt"></div></span>
- </pre></div>
- </div>
- </div>
- </div>
- </div>
- </div>
- <div id="docs-bottom-navigation" class="docs-navigation-links">
- Previous:
- <a href="namespaces.html" title="previous chapter">Namespaces</a>
- Next:
- <a href="filtering.html" title="next chapter">Filtering and Buffering</a>
- <div id="docs-copyright">
- © Copyright the Mako authors and contributors.
- Documentation generated using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3
- with Mako templates.
- </div>
- </div>
- </div>
- <div class="clearfix">
- <hr/>
- <div class="copyright">Website content copyright © by Michael Bayer.
- All rights reserved. Mako and its documentation are licensed
- under the MIT license. mike(&)zzzcomputing.com</div>
- </div>
- </div>
- </body>
- </html>
|