gistfile1.txt

{# =====================================================================
  COMMENTS (all forms)
===================================================================== #}

{# single line #}
{##
  multiline
  block
##}

{# =====================================================================
  EXPRESSIONS & LITERALS
===================================================================== #}

{{ "string" }}
{{ 'string' }}
{{ 0 }}
{{ -1 }}
{{ 3.1415 }}
{{ true }}
{{ false }}
{{ none }}

{{ [] }}
{{ {} }}
{{ () }}

{{ [1, "a", true, none] }}
{{ {"a": 1, "b": [1, 2], "c": {"x": 1}} }}
{{ (1, 2, 3) }}

{{ "a" ~ 1 ~ true }}

{{ 1 + 2 }}
{{ 5 - 3 }}
{{ 2 * 3 }}
{{ 8 / 4 }}
{{ 7 // 3 }}
{{ 7 % 3 }}

{{ (1 + 2) * (3 + 4) }}

{{ 1 < 2 }}
{{ 2 > 1 }}
{{ 1 <= 1 }}
{{ 2 >= 1 }}
{{ 1 == 1 }}
{{ 1 != 2 }}

{{ true and false }}
{{ true or false }}
{{ not false }}

{{ a if a is defined else "fallback" }}

{# =====================================================================
  SET STATEMENTS
===================================================================== #}

{% set a = 1 %}
{% set b = 2 %}
{% set c = a + b %}

{% set x, y = 10, 20 %}
{% set x = x + 1 %}

{% set ns = namespace(total=0, items=[]) %}
{% set ns.total = ns.total + 1 %}

{# =====================================================================
  IF / ELIF / ELSE (deep nesting + expressions)
===================================================================== #}

{% if a is defined and a > 0 %}
  {% if b is defined and b > 0 %}
    BOTH POSITIVE
  {% elif b == 0 %}
    B ZERO
  {% else %}
    B NEGATIVE
  {% endif %}
{% elif a == 0 %}
  A ZERO
{% else %}
  A NEGATIVE
{% endif %}

{# inline if-expression #}
{{ "yes" if a > 0 else "no" }}

{# =====================================================================
  FOR LOOPS (all legal variants)
===================================================================== #}

{# simple for #}
{% for i in [1, 2, 3] %}
  {{ i }}
{% endfor %}

{# for with unpacking #}
{% for k, v in {"a": 1, "b": 2}.items() %}
  {{ k }}={{ v }}
{% endfor %}

{# for with if filter #}
{% for i in [1, 2, 3, 4, 5] if i is odd %}
  ODD {{ i }}
{% endfor %}

{# for with loop variables #}
{% for i in [10, 20, 30] %}
  {{ loop.index }} {{ loop.index0 }}
  {{ loop.first }} {{ loop.last }}
  {{ loop.length }}
{% endfor %}

{# nested for #}
{% for row in [[1, 2], [3, 4]] %}
  {% for col in row %}
    {{ col }}
  {% endfor %}
{% endfor %}

{# for + else #}
{% for x in empty %}
  {{ x }}
{% else %}
  EMPTY ITERABLE
{% endfor %}

{# =====================================================================
  FILTERS (all application forms)
===================================================================== #}

{{ "abc"|upper }}
{{ "ABC"|lower }}
{{ " abc "|trim }}
{{ [3, 2, 1]|sort }}
{{ {"a": 1, "b": 2}|length }}

{{ value|default("fallback") }}
{{ value|default("fallback", true) }}

{{ [1, 2, 3]|join(",") }}
{{ "hello"|replace("h", "H") }}

{{ " abc "|trim|upper|replace("A", "X") }}

{# filter in expression #}
{{ ("abc"|upper) == "ABC" }}

{# =====================================================================
  TESTS (all base tests + compositions)
===================================================================== #}

{% if value is defined %}DEFINED{% endif %}
{% if value is not defined %}NOT DEFINED{% endif %}

{% if value is none %}NONE{% endif %}
{% if value is boolean %}BOOLEAN{% endif %}
{% if value is string %}STRING{% endif %}
{% if value is number %}NUMBER{% endif %}
{% if value is sequence %}SEQUENCE{% endif %}
{% if value is mapping %}MAPPING{% endif %}
{% if value is iterable %}ITERABLE{% endif %}
{% if value is callable %}CALLABLE{% endif %}

{% if 3 is odd %}ODD{% endif %}
{% if 4 is even %}EVEN{% endif %}

{% if 2 is greaterthan 1 %}GT{% endif %}
{% if 1 is lessthan 2 %}LT{% endif %}
{% if 2 is equalto 2 %}EQ{% endif %}

{% if "a" in ["a", "b", "c"] %}IN{% endif %}
{% if "x" not in ["a", "b"] %}NOT IN{% endif %}

{# =====================================================================
  MACROS (args, defaults, nesting)
===================================================================== #}

{% macro greet(name, title="Mr.") %}
Hello {{ title }} {{ name }}
{% endmacro %}

{{ greet("John") }}
{{ greet("John", title="Dr.") }}

{% macro list_items(items) %}
{% for item in items %}
- {{ item }}
{% endfor %}
{% endmacro %}

{{ list_items([1, 2, 3]) }}

{% macro outer(value) %}
  {% macro inner(v) %}
    {{ v }}
  {% endmacro %}
  {{ inner(value) }}
{% endmacro %}

{{ outer("X") }}

{# =====================================================================
  CALL / CALLER (nested)
===================================================================== #}

{% macro wrapper(tag="div") %}
<{{ tag }}>
  {{ caller() }}
</{{ tag }}>
{% endmacro %}

{% call wrapper("section") %}
  {% call wrapper("span") %}
    TEXT
  {% endcall %}
{% endcall %}

{# =====================================================================
  BLOCKS (nested, override-safe)
===================================================================== #}

{% block header %}
  HEADER
{% endblock %}

{% block content %}
  {% block inner %}
    INNER
  {% endblock %}
{% endblock %}

{% block footer %}
  FOOTER
{% endblock %}

{# =====================================================================
  WHITESPACE CONTROL
===================================================================== #}

{%- if true -%}
TRIMMED
{%- endif -%}

{{- "LEFT" }}
{{ "RIGHT" -}}

{# =====================================================================
  RAW
===================================================================== #}

{% raw %}
{{ not_evaluated }}
{% if also_not %}
{% endraw %}

{# =====================================================================
  ESCAPING
===================================================================== #}

{{ "<b>bold</b>" }}
{{ "<b>bold</b>"|safe }}

{# =====================================================================
  IMPORT / FROM (syntax only)
===================================================================== #}

{% import "macros.j2" as m %}
{% from "macros.j2" import greet as imported_greet %}

{# =====================================================================
  INCLUDE (syntax only)
===================================================================== #}

{% include "partial.j2" %}

{# =====================================================================
  EXTENDS (syntax only)
===================================================================== #}

{% extends "base.j2" %}