Built-in template tags and filters

Built-in Tags

for

A for loop allows you to iterate over an array found by variable lookup.

<ul>
  {% for user in users %}
    <li>{{ user }}</li>
  {% endfor %}
</ul>

The for tag can take an optional {% empty %} block that will be displayed if the given list is empty or could not be found.

<ul>
  {% for user in users %}
    <li>{{ user }}</li>
  {% empty %}
    <li>There are no users.</li>
  {% endfor %}
</ul>

The for block sets a few variables available within the loop:

• first - True if this is the first time through the loop
• last - True if this is the last time through the loop
• counter - The current iteration of the loop

if

The {% if %} tag evaluates a variable, and if that variable evaluates to true the contents of the block are processed. Being true is defined as:

• Present in the context
• Being non-empty (dictionaries or arrays)
• Not being a false boolean value
• Not being a numerical value of 0 or below
• Not being an empty string

{% if variable %}
  The variable was found in the current context.
{% else %}
  The variable was not found.
{% endif %}

Operators

if tags may combine and, or and not to test multiple variables or to negate a variable.

{% if one and two %}
    Both one and two evaluate to true.
{% endif %}

{% if not one %}
    One evaluates to false
{% endif %}

{% if one or two %}
    Either one or two evaluates to true.
{% endif %}

{% if not one or two %}
    One does not evaluate to false or two evaluates to true.
{% endif %}

You may use and, or and not multiple times together. not has higest prescidence followed by and. For example:

{% if one or two and three %}

Will be treated as:

one or (two and three)

== operator

{% if value == other_value %}
  value is equal to other_value
{% endif %}

Note

The equality operator only supports numerical, string and boolean types.

!= operator

{% if value != other_value %}
  value is not equal to other_value
{% endif %}

Note

The inequality operator only supports numerical, string and boolean types.

< operator

{% if value < other_value %}
  value is less than other_value
{% endif %}

Note

The less than operator only supports numerical types.

<= operator

{% if value <= other_value %}
  value is less than or equal to other_value
{% endif %}

Note

The less than equal operator only supports numerical types.

> operator

{% if value > other_value %}
  value is more than other_value
{% endif %}

Note

The more than operator only supports numerical types.

>= operator

{% if value >= other_value %}
  value is more than or equal to other_value
{% endif %}

Note

The more than equal operator only supports numerical types.

ifnot

Note

{% ifnot %} is deprecated. You should use {% if not %}.

{% ifnot variable %}
  The variable was NOT found in the current context.
{% else %}
  The variable was found.
{% endif %}

now

include

You can include another template using the include tag.

{% include "comment.html" %}

The include tag requires a FileSystemLoader to be found inside your context with the paths, or bundles used to lookup the template.

let context = Context(dictionary: [
  "loader": FileSystemLoader(bundle: [NSBundle.mainBundle()])
])

extends

block

Built-in Filters

capitalize

The capitalize filter allows you to capitalize a string. For example, stencil to Stencil.

{{ "stencil"|capitalize }}

uppercase

The uppercase filter allows you to transform a string to uppercase. For example, Stencil to STENCIL.

{{ "Stencil"|uppercase }}

lowercase

The uppercase filter allows you to transform a string to lowercase. For example, Stencil to stencil.

{{ "Stencil"|lowercase }}

default

If a variable not present in the context, use given default. Otherwise, use the value of the variable. For example:

Hello {{ name|default:"World" }}

join

Join an array with a string.

{{ value|join:", " }}

Note

The value MUST be an array of Strngs and the separator must be a string.