E-mail quoting filters and tags

class QuotedEmail(template.Node):
    def __init__(self, template_name):
        self.template_name = template_name

    def render(self, context):
        return quote_text(render_to_string(self.template_name, context))


@register.tag
def quoted_email(parser, token):
    try:
        tag_name, template_name = token.split_contents()
    except ValueError:
        raise template.TemplateSyntaxError, "%r tag requires a template name"

    return QuotedEmail(template_name)


@register.filter
def quote_text(text, level=1):
    lines = text.split("\n")
    quoted = ""

    for line in lines:
        quoted += "%s%s\n" % ("> " * level, line)

    return quoted.rstrip()