Jinja2 Support

Accent CMS templates use Jinja2 syntax. This page is a complete reference of every built-in filter, test, function, and syntax construct available to theme developers and content authors.

For Accent CMS-specific template features (custom filters, page context, collections), see the Templating Guide.

Template Syntax

Variables

Output a value with double curly braces:

{{ page.title }}
{{ site.name }}

Tags

Execute logic with {% %} blocks:

{% if page.tags %}
  Tagged content
{% endif %}

{% for item in items %}
  {{ item.title }}
{% endfor %}

Comments

Comments are stripped from output:

{# This is a comment #}

Template Inheritance

Define a base layout with replaceable blocks:

{# base.html.jinja #}
<html>
<body>
  {% block content %}default content{% endblock %}
</body>
</html>

Child templates extend the base and override blocks:

{# page.html.jinja #}
{% extends "base.html.jinja" %}
{% block content %}
  <h1>{{ page.title }}</h1>
  {{ page.content | safe }}
{% endblock %}

The child template’s block content replaces the parent’s. Blocks not overridden keep their default content.

Includes

Pull in another template fragment:

{% include "partials/header.html.jinja" %}

The included template has access to the current context.

Macros

Define reusable template functions:

{# macros.html.jinja #}
{% macro button(label, url) %}
  <a href="{{ url }}" class="btn">{{ label }}</a>
{% endmacro %}

Import and use macros in other templates:

{% from "macros.html.jinja" import button %}
{{ button("Click me", "/action") }}

Whitespace Control

Add a hyphen to strip whitespace around tags:

{%- if true -%}
  tight
{%- endif -%}

This produces tight with no surrounding whitespace. Works with {{- -}} for expressions too.

Auto-escaping

HTML special characters in variable output are automatically escaped:

{# If user_input = "<script>alert(1)</script>" #}
{{ user_input }}
{# Output: &lt;script&gt;alert(1)&lt;/script&gt; #}

Use the safe filter to output trusted HTML without escaping:

{{ page.content | safe }}

For Loops

Basic Loop

{% for item in items %}
  {{ item }}
{% endfor %}

Loop Object

Inside a for loop, the loop variable provides iteration metadata:

Property	Description
loop.index	Current iteration (1-indexed)
loop.index0	Current iteration (0-indexed)
loop.revindex	Iterations remaining (1-indexed)
loop.revindex0	Iterations remaining (0-indexed)
loop.first	true on the first iteration
loop.last	true on the last iteration
loop.length	Total number of items
loop.depth	Nesting depth (starts at 1)
loop.depth0	Nesting depth (starts at 0)

Example:

{% for page in pages %}
  {{ loop.index }}/{{ loop.length }}: {{ page.title }}
  {% if loop.first %}(first){% endif %}
  {% if loop.last %}(last){% endif %}
{% endfor %}

Built-in Filters

Filters transform values using the pipe (|) operator: {{ value|filter }}.

String Filters

Filter	Example	Result
capitalize	{{ "hello WORLD"|capitalize }}	Hello world
lower	{{ "HELLO"|lower }}	hello
upper	{{ "hello"|upper }}	HELLO
title	{{ "hello world"|title }}	Hello World
trim	{{ " hello "|trim }}	hello
replace	{{ "hello"|replace("l", "r") }}	herro
split	{{ "a,b,c"|split(",") }}	["a", "b", "c"]
lines	{{ "a\nb\nc"|lines|list }}	["a", "b", "c"]
indent	{{ "a\nb"|indent(4) }}	Indented lines
format	{{ "%s is %d"|format("age", 30) }}	age is 30

Number Filters

Filter	Example	Result
abs	{{ (-3)|abs }}	3
float	{{ "3.14"|float }}	3.14
int	{{ "42"|int }}	42
round	{{ 3.456|round(2) }}	3.46

List Filters

Filter	Example	Result
first	{{ [10, 20, 30]|first }}	10
last	{{ [10, 20, 30]|last }}	30
length	{{ [1, 2, 3]|length }}	3
join	{{ ["a", "b", "c"]|join(", ") }}	a, b, c
reverse	{{ "abc"|reverse }}	cba
sort	{{ [3, 1, 2]|sort }}	[1, 2, 3]
unique	{{ [1, 2, 2, 3]|unique|list }}	[1, 2, 3]
min	{{ [3, 1, 2]|min }}	1
max	{{ [3, 1, 2]|max }}	3
sum	{{ [1, 2, 3]|sum }}	6
batch	{{ [1,2,3,4,5]|batch(2)|list }}	[[1, 2], [3, 4], [5]]
slice	{{ [1,2,3,4,5]|slice(2)|list }}	[[1, 2, 3], [4, 5]]
chain	{{ [1, 2]|chain([3, 4])|list }}	[1, 2, 3, 4]
zip	{{ [1, 2]|zip(["a", "b"])|list }}	[[1, "a"], [2, "b"]]

Selection Filters

Filter	Example	Result
select	{{ [1,2,3,4]|select("odd")|list }}	[1, 3]
reject	{{ [1,2,3,4]|reject("odd")|list }}	[2, 4]
selectattr	{{ items|selectattr("active")|list }}	Items where active is truthy
rejectattr	{{ items|rejectattr("draft")|list }}	Items where draft is falsy
map	{{ items|map(attribute="title")|list }}	List of title values
groupby	{{ items|groupby("category") }}	Items grouped by category

Dictionary Filters

Filter	Example	Result
items	{{ {"a": 1}|items|list }}	[["a", 1]]
dictsort	{{ {"b": 2, "a": 1}|dictsort }}	[["a", 1], ["b", 2]]
attr	{{ obj|attr("name") }}	Value of obj.name

Type Conversion Filters

Filter	Example	Result
bool	{{ ""|bool }}	false
int	{{ "42"|int }}	42
float	{{ "3.14"|float }}	3.14
string	{{ 42|string }}	42
list	{{ "abc"|list }}	["a", "b", "c"]

Output Filters

Filter	Example	Result
default	{{ missing|default("fallback") }}	fallback
escape / e	{{ "<b>"|escape }}	&lt;b&gt;
safe	{{ "<b>bold</b>"|safe }}	<b>bold</b> (no escaping)
pprint	{{ value|pprint }}	Debug representation

Built-in Tests

Tests check conditions using the is operator: {% if value is test %}.

Type Tests

Test	Example	True when
boolean	value is boolean	Value is true or false
integer	value is integer	Value is an integer
float	value is float	Value is a floating-point number
number	value is number	Value is any number (integer or float)
string	value is string	Value is a string
sequence	value is sequence	Value is a list/array
mapping	value is mapping	Value is a dictionary/object
iterable	value is iterable	Value can be iterated over

Value Tests

Test	Example	True when
true	value is true	Value is exactly true
false	value is false	Value is exactly false
sameas	a is sameas b	a and b are the same object
in	1 is in [1, 2, 3]	Value is contained in the sequence

Comparison Tests

Test	Example	True when
eq / equalto / ==	value is eq 1	Equal to
ne / !=	value is ne 2	Not equal to
gt / greaterthan / >	value is gt 5	Greater than
ge / >=	value is ge 5	Greater than or equal
lt / lessthan / <	value is lt 5	Less than
le / <=	value is le 5	Less than or equal

Number Tests

Test	Example	True when
odd	value is odd	Value is an odd number
even	value is even	Value is an even number
divisibleby	value is divisibleby(3)	Value is divisible by the argument

String Tests

Test	Example	True when
lower	value is lower	All characters are lowercase
upper	value is upper	All characters are uppercase
startingwith	value is startingwith "foo"	String starts with the argument
endingwith	value is endingwith "bar"	String ends with the argument

Introspection Tests

Test	Example	True when
filter	"lower" is filter	The named filter exists
test	"boolean" is test	The named test exists

Built-in Functions

Functions are called directly in expressions.

range

Generate a sequence of numbers:

{{ range(5)|list }}
{# [0, 1, 2, 3, 4] #}

{{ range(2, 8)|list }}
{# [2, 3, 4, 5, 6, 7] #}

{{ range(0, 10, 2)|list }}
{# [0, 2, 4, 6, 8] #}

dict

Create a dictionary:

{{ dict(name="Alice", age=30) }}

Can merge with an existing dictionary:

{% set base = {"a": 1, "b": 2} %}
{{ dict(base, c=3) }}

namespace

Create a mutable namespace object. Useful for updating values inside loops (regular variables are scoped to blocks):

{% set ns = namespace(count=0) %}
{% for item in items %}
  {% set ns.count = ns.count + 1 %}
{% endfor %}
Total: {{ ns.count }}

debug

Output debug information about a value. Accent requires a value argument:

{{ debug(page) }}

Returns a string representation of the given value. Useful during template development.