django-smart-load-tag

An attempt to bring namespaces and more control to Django's {% load %} tag.

This project includes two tags: {% import %} and a replacement for the built-in {% load %}. Both provide a similar feature set. The primary difference is that {% import %} namespaces by default, where {% load %} does not, retaining backwards compatibility with Django's built-in {% load %} tag.

installation

To install, first install the package to your system using either of the following:

pip install django-smart-load-tag
easy_install django-smart-load-tag

Then you must install into your Django project by adding "smart_load_tag" to your settings.INSTALLED_APPS.

If you want to use django-smart-load-tag without loading it into every template, you can install it globally by adding it to your builtin tags. Just add the following to your urlconf (usually urls.py):

try:
    from django.template.base import add_to_builtins
except ImportError:  # Django < 1.8
    from django.template import add_to_builtins
add_to_builtins('smart_load_tag.templatetags.smart_load')

introduction

After loading, the smart {% load %} tag replaces the existing load tag, as it is backwards-compatible. It provides features that the existing load tag lacks:

templatetag namespaces:

{% load my_tags into cool_tags %}    # Load library ``my_tags`` into namespace ``cool_tags``.
{% cool_tags.my_tag %}               # Usage of tag ``my_tag`` imported above as part of the template library ``my_tags``.

load only a single tag from a library:

{% load lib.tag_name %}    # Load tag ``tag_name`` from templatetag library ``lib``.
{% tag_name %}             # Usage of tag imported above.

load library from a specific application:

{% load lib from my_app %}    # Ensure that library is loaded from my_app (by default, this will load the last library of that name in all your INSTALLED_APPS).

load tag as different name

{% load my_tags.foo_tag as my_foo_tag %}    # Load tag ``foo_tag`` from library ``my_tags`` and assign to name ``my_foo_tag``
{% my_foo_tag %}                            # Usage of tag imported above.

Thus, the syntax for the tag is described by this psuedo-regex:

{% load (lib_name(.tag_name)?( from app)?( as name)?( into namespace)?,? )+ %}

examples

Any combination of from, as, and into clauses are acceptable:

{% load foo_tags.my_tag from my_app into cool_tags as my_cool_tag %}    # lib foo_tags, tag my_tag, app my_app, namespace cool_tags, name my_cool_tag
{% cool_tags.my_cool_tag %}                                             # Usage

Note that the combination of into and as are not needed, as the following two lines are equivalent:

{% load foo_tags.my_tag into cool_tags as my_cool_tag %}
{% load foo_tags.my_tag as cool_tags.my_cool_tag %}

Multiple loads can be on the same line, optionally comma separated, enabling more complex combinations such as this:

{% load foo_tags from app1 into app1_foo_tags, foo_tags from app2, bar_tags.render_content as render_bar_content %}
{% app1_foo_tags.render_content %}    # from ``foo_tags from app1 into app1_foo_tags``
{% render_content %}                  # from ``foo_tags from app2``
{% render_bar_content %}              # from ``bar_tags.render_content as render_bar_content``

The functionality provided by django-smart-load-tag is a progressive enhancement, and can be safely loaded into any template, as it remains backwards-compatible with Django's built-in {% load %} tag.

alternative syntax

The {% load %} replacement is intended to be backwards compatible, but a new tag also exists, {% import %} that provides a syntax that defaults to providing a namespace, while allowing you to opt-out of namespacing the loaded tags (using * from).

The following table illustrates the differences in syntax from the smart {% load %} tag.

{% import %} syntax {% load %} syntax

{% import foo_tags %} {% load foo_tags into foo_tags %}

{% import foo_tags from app1 %} {% load foo_tags from app1 into foo_tags %}

{% import foo_tags.my_tag %} {% load foo_tags.my_tag as foo_tags.my_tag %}

{% import foo_tags from my_app as my_foo %} {% load foo_tags from my_app into my_foo %}

{% import foo_tags.my_tag as my_foo_tag %} {% load foo_tags.my_tag as my_foo_tag %}

{% import * from foo_tags %} {% load foo_tags %}

{% import * from foo_tags from app1 %} {% load foo_tags from app1 %}

{% import %} syntax	{% load %} syntax
{% import foo_tags %}	{% load foo_tags into foo_tags %}
{% import foo_tags from app1 %}	{% load foo_tags from app1 into foo_tags %}
{% import foo_tags.my_tag %}	{% load foo_tags.my_tag as foo_tags.my_tag %}
{% import foo_tags from my_app as my_foo %}	{% load foo_tags from my_app into my_foo %}
{% import foo_tags.my_tag as my_foo_tag %}	{% load foo_tags.my_tag as my_foo_tag %}
{% import * from foo_tags %}	{% load foo_tags %}
{% import * from foo_tags from app1 %}	{% load foo_tags from app1 %}

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