templates.py

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

import re

from django.template import Variable, VariableDoesNotExist
from django.template.base import FilterExpression, kwarg_re, TemplateSyntaxError

"""
Extra features for template file handling
"""


QUOTED_STRING = re.compile(r'^["\'](?P<noquotes>.+)["\']$')


def handle_var(value, context):
    # Resolve FilterExpression and Variable immediately
    if isinstance(value, FilterExpression) or isinstance(value, Variable):
        return value.resolve(context)
    # Return quoted strings unquotes, from djangosnippets.org/snippets/886
    stringval = QUOTED_STRING.search(value)
    if stringval:
        return stringval.group('noquotes')
    # Resolve variable or return string value
    try:
        return Variable(value).resolve(context)
    except VariableDoesNotExist:
        return value


def parse_token_contents(parser, token):
    bits = token.split_contents()
    tag = bits.pop(0)
    args = []
    kwargs = {}
    asvar = None
    if len(bits) >= 2 and bits[-2] == 'as':
        asvar = bits[-1]
        bits = bits[:-2]
    if len(bits):
        for bit in bits:
            match = kwarg_re.match(bit)
            if not match:
                raise TemplateSyntaxError(
                      'Malformed arguments to tag "{}"'.format(tag))
            name, value = match.groups()
            if name:
                kwargs[name] = parser.compile_filter(value)
            else:
                args.append(parser.compile_filter(value))
    return {
        'tag': tag,
        'args': args,
        'kwargs': kwargs,
        'asvar': asvar,
    }