Make sure we don't create an infinite loop with a self-referencing foreign key.
Many times I have needed category models that reference themselves, providing a flexible way to make children categories, grandchildren categories, etc. If you chain the slugs (or even ids) there's a chance you could end up with an infinite loop.
Assumes a required, unique slug field ('slug') and an optional self-referencing foreign key
('parent'). All_data doesn't give you the object's ID, so we will find it via the unique slug.
If either is not present we pass -- if there's no parent chosen it's not a problem, and if there
is no slug present the submission will fail on that validation instead. It is worth noting that
if the user changes the slug field on submission AND picks a bad parent it will not be caught.
Infinite loop cases:
1. A references A
2. A tries to reference B, which is currently referencing A
A simple macro system that makes it possible to reuse previously defined
blocks, optionally with a custom context, similar to the macro
functionality in Jinja.
It requires some workarounds/hacks because we cannot reach
all the data from inside the django template system that we need, but it
seems to work pretty well so far. It is, however, also pretty untested at this point, so use at your own risk.
Examples:
base.html:
<!--
This is mandatory if you want to use the repeat-tag in
a template. It should as placed as earily as possible.
See below for how to mix with template inheritance.
-->
{% enablemacros %}
<!-- Note that {{ param }} does not exist. -->
{% block foo %}
A standard django block that will be written to the output.
{% if param %}{{ param }}{% endif %}
{% endblock %}
{% macro bar %}
Pretty much the same thing as a django block (can even be
overridden via template inheritance), but it's content
will NOT be rendered per default. Please note that it
ends with ENDBLOCK!
{% if param %}{{ param }}{% endif %}
{% endblock %}
<!-- Render foo for the second time -->
{% repeat foo %}
<!-- Render foo bar the first time -->
{% repeat bar %}
<!-- Render both blocks again, and pass a parameter -->
{% repeat foo with "Hello World" as param %}
{% repeat bar with "Hello World" as param %}
{% macro form %}do stuff with: {{ form }}{% endblock %}
{% for form in all_forms %}
{% repeat display %} <!-- will have access to {{ form }}
{% endfor %}
extend.html:
<!--
{% extends %} requires that it be the first thing in a template,
and if it is, everything except for block tags is ignored, so
{% enablemacros %} won't work. Instead, use:
-->
{% extends_with_macros 'base.html' %}
{% block foo %}
Will override "foo" in base.html
{% endblock %}
{% block bar %}
Will override the macro block "bar" in base.html. Whether
this is defined as block or macro doesn't matter.
{% endblock %}
Todo:
* This (both tags used) results in infinite recursion:
{% extends_with_macros "somefile" %}{% enablemacros %}
- templates
- macro
- jinja
- repeat
- reuse
- variables