How does the {{ form }} tag work in Django-registration app

Question

I downloaded and installed django-registration app. I also downloaded a template that has this strange piece of code

{{ form }}

that magically creates 4 labels and 4 textboxes for the user to enter his registration information. How does it work?

{% extends "registration/registration_base.html" %}
{% block title %}Register for an account{% endblock %}
{% block content %}

<table>
    <form method='post' action=''>{% csrf_token %}
        {{ form }}
        <tr><td></td><td><input type="submit" value="Send activation email" /></td>
    </form>
</table>
{% endblock %}

Answer 1

It is part of django forms. See the documentation for more info.

https://docs.djangoproject.com/en/1.3/topics/forms/

If you are really interested check out the source code.

https://code.djangoproject.com/browser/django/trunk/django/forms

Answer 2

A django form (but other objects, too) has a unicode method, which is invoked, when a string representation of the object is requested. As you can see in the code, it just passes the call on to as_table - which in turn uses a generic helper function: _html_output . This basically loops over all the fields and constructs the HTML which then is returned and displayed on the page.