Template Markup

There are three kinds of template markup: comments, print statements, and syntax tags. Comments are the simplest kind; they look like this:

{# This is a comment. #}

Comments can span multiple lines and can be used to comment-out sections of template code.

Print statements evaluate and print expressions. They look like this:

{{ post.title }}

Print statements come in two flavours: regular and escaped. Escaped print statements escape HTML syntax characters in their output before printing it. They look like this:

{{{ post.title }}}

Escaped print statements are simply a shortcut for applying the built-in escape filter to their content. The example above is equivalent to:

{{ post.title|escape }}

Print statements can make use of two other constructs. First, print statements can contain multiple expressions separated by the or keyword. The first expression to evaluate as 'truthy' will be printed:

{{ post.title or "Untitled Post" }}

Second, print statements can make use of a C-style ternary operator, ?? :::

{{ is_homepage ?? site.title :: post.title }}

If the first (test) expression evaluates as 'truthy', the value of the second expression will be printed, otherwise the value of the third expression will be used.

Note that a single print statement can make use of or-chaining or the ternary construct, but not both.

Expressions

An expression consists of a variable name or a Python literal, optionally followed by a chain of pipe-separated filters.

Variables use . syntax to drill into nested dictionaries or objects. If a variable evaluates to a callable it gets called automatically. If the callable requires arguments you can supply them using colon or bracket syntax:

{{ some.callable:42:"foo" }}

{{ some.callable(42, "foo") }}

Filters are chainable functions that modify the value of an expression. You apply them using the pipe symbol:

{{ post.title|escape }}

Like callables, filters accept arguments using colon or bracket syntax:

{{ post.content|striptags|truncatewords:50 }}

You can find a list of built-in filters here.

Note that expressions can use simple Python literals in place of variables:

{% if day|lower in ("saturday", "sunday") %}
    It's the weekend!
{% endif %}

The following literal structures can be used in expressions as arguments to callables or in place of variables: strings, bytes, numbers, tuples, lists, dicts, sets, booleans, and None.

Syntax Tags

Syntax tags implement a broad range of behaviours like looping, conditional branching, and template inheritance. They look like this:

{% tag %}

Some syntax tags have block scope and require a closing tag. They look like this:

{% tag %} ... {% endtag %}

Tags with block scope can contain further template markup and can be nested to any depth.

You can find a list of built-in syntax tags here.