Q:

Writing a Template Tag in Django

I'm trying to customise a CMS written in Django.  The content editors aren't flexible enough so I'm trying to come up with a better solution. 
Without over-explaining it, I'd like it to be a bit like django-better-chunks or django-flatblocks.  You set up an editable region entirely from within the template.  I want to bind these editable regions to a mix of strings and object instances.  One example would be having multiple editable regions based on one product:
{% block product_instance "title" %}
{% block product_instance "product description" %}

So if you have a view with another product as product_instance those two blocks would show different data.  I would also see there being use for site-wide blocks that only pass through the string part.  Essentially, I would like to be able to pass 1-infinity identifiers. 
But I'm really struggling on two fronts here:

How do I define the relationship between the mixed identifier and the actual content "block" instance?  I have a feeling contenttypes might feature here but I've really no idea where to start looking! 
And how do I write a template tag to read the above syntax and convert that into an object for rendering? 

A:

for this you can create an inclusion tag and use it like:
{% load my_tags %}
{% product bicycle <extra vars ...> %}

To define the tag, add to your app/templatetags/mytags.py:
@register.inclusion_tag('results.html')
def product(item, *extra):
    #maybe repackage extra variables
    #and add them to the returned dictionary
    item_form = ItemForm(item) #form. ModelForm instance
    return {'item': item, 'item_form':item_form, ...}

Then you'll need a template that returns html for the item:
<h1>{{item.title}}</h1>
{{item_form}}
... add some conditional statements depending on extra vars

