mytags.py

""" My tag library. """

from django.template import Node, NodeList, Template, Context, Variable
from django.template import TemplateSyntaxError, VariableDoesNotExist, BLOCK_TAG_START, BLOCK_TAG_END, VARIABLE_TAG_STAR
T, VARIABLE_TAG_END, SINGLE_BRACE_START, SINGLE_BRACE_END, COMMENT_TAG_START, COMMENT_TAG_END
from django.template import get_library, Library, InvalidTemplateLibrary
from django.conf import settings
from django.utils.encoding import smart_str, smart_unicode
from django.utils.itercompat import groupby
from django.utils.safestring import mark_safe

register = Library()


class NowWithDeltaNode(Node):
    def __init__(self, format_string, delta):
        self.format_string = format_string
        self.delta = delta
    def render(self, context):
        from datetime import datetime, timedelta
        from django.utils.dateformat import DateFormat
        td = timedelta(int(self.delta)) if self.delta else timedelta(0)
        df = DateFormat(datetime.now() + td)
        return df.format(self.format_string.strip('"'))

#@register.tag
def now_with_delta(parser, token):
    """
    Displays the date, formatted according to the given string with delta.

    Uses the same format as PHP's ``date()`` function; see http://php.net/date
    for all the possible values.

    Sample usage::

    Yesterday is {% now_with_delta "jS F Y H:i" -1 %}
    Tomorrow is {% now_with_delta "jS F Y H:i" 1 %}
    """
    bits = token.split_contents()
    if len(bits) < 2:
        raise TemplateSyntaxError, "%r statement takes at least 1 argument" % bits[0]
    format_string = bits[1]
    delta = None if len(bits) == 2 else bits[2]
    return NowWithDeltaNode(format_string, delta)
now_with_delta = register.tag(now_with_delta)