Template Inheritance

Ibis supports Django-style template inheritance. Template inheritance allows you to create a single parent template containing common boilerplate code and then override specific sections of it in child templates.

Template inheritance is best explained with an example. Let's start with a skeleton HTML template which we'll call base.html:

<!DOCTYPE html>
<html>
    <head>
        <title>
            {% block title %}My Site Title{% endblock %}
        </title>
    </head>
    <body>
        <div id="sidebar">
            {% block sidebar %}
                <ul>
                    <li><a href="/">Home</a></li>
                    <li><a href="/blog/">Blog</a></li>
                </ul>
            {% endblock %}
        </div>
        <div id="content">
            {% block content %}{% endblock %}
        </div>
    </body>
</html>

This template uses block tags to define three blocks of content that child templates can override with specific content of their own. Child templates use the extends tag to declare that they inherit from a particular base template:

{% extends "base.html" %}

{% block title %}My Homepage{% endblock %}

{% block content %}
    <h1>My Homepage</h1>
    <p>Here's some waffle about my wonderful site...</p>
{% endblock %}

In this case we didn't override the sidebar block so the default content from the parent template will be used as a fallback.

Some points to note:

The extends tag should be the first tag in a child template.
Apart from the extends tag, the child template should contain only block tags and their content.
The extends tag takes a string-literal argument specifying the name of the parent template.
You need to configure a template loader so Ibis can locate the appropriate parent template.
You can use as many levels of inheritance as you like.
Within a child block, the built-in {{ super() }} function gives you access to the content of the parent block.