Extending templates with `extends` and `block`

Start with a template that contains one or more blocks:

<!DOCTYPE html>
<main>
{%- block content %}
  <p>Parent content.</p>
{% endblock -%}
</main>

Then create a template to extend it:

{% extends "layout.html.oxip" %}

This is essentially the same as using layout.html.oxip directly:

<!DOCTYPE html>
<main>
  <p>Parent content.</p>
</main>

Adding to or replacing block content

Anything you add to a block of the same name in a child template will replace the content of the parent block:

  {% extends "layout.html.oxip" %}

+ {% block content %}
+   <p>Replaced content.</p>
+ {% endblock %}

  <!DOCTYPE html>
  <main>
-   <p>Parent content.</p>
+   <p>Replaced content.</p>
  </main>

The parent's content can be kept by using the {% parent %} tag in the block:

  {% extends "layout.html.oxip" %}+

+ {% block(surround) content %}
+   <p>Prefix.</p>
+   {% parent %}
+   <p>Suffix.</p>
+ {% endblock %}

  <!DOCTYPE html>
  <main>
+   <p>Prefix.</p>
    <p>Parent content.</p>
+   <p>Suffix.</p>
  </main>