Sometimes, we might want to calculate or process a value directly in the templates. Jinja2 maintains a notion that the processing of logic should be handled in views and not in templates, and thus, it keeps the templates clean. A context processor becomes a handy tool in this case. We can pass our values to a method; this will then be processed in a Python method, and our resultant value will be returned. Therefore, we are essentially just adding a function to the template context (thanks to Python for allowing us to pass around functions just like any other object).

@product_blueprint.context_processor:
def some_processor():
    def full_name(product):
        return '{0} / {1}'.format(product['category'], product['name'])
    return {'full_name': full_name}