class ChoiceEnum(object):
    """
    A class to encapsulate handy functionality for lists of choices
    for a Django model field.

    Accepts verbose choice names as arguments, and automatically
    assigns numeric keys to them. When iterated over, behaves as the
    standard Django choices tuple of two-tuples.

    Attribute access allows conversion of verbose choice name to
    choice key, dictionary access the reverse.

    Example:

    >>> STATUS = ChoiceEnum('DRAFT', 'PUBLISHED')
    >>> STATUS.DRAFT
    0
    >>> STATUS[1]
    'PUBLISHED'
    >>> tuple(STATUS)
    ((0, 'DRAFT'), (1, 'PUBLISHED'))
    
    >>> STATUS = ChoiceEnum(('DRAFT', 'draft'), ('PUBLISHED', 'published'))
    >>> STATUS.DRAFT
    0
    >>> tuple(STATUS)
    ((0, 'draft'), (1, 'published'))

    """

    def __init__(self, *choices):
        self._choices = tuple()
        self._iter_choices = tuple()
        for i, choice in enumerate(self.equalize(choices)):
            self._choices += ((i, choice[0]),)
            self._iter_choices += ((i, choice[1]),)
            self.set_display(choice[0], choice[1])
        self._choice_dict = dict(self._choices)
        self._reverse_dict = dict(((i[1], i[0]) for i in self._choices))

    def equalize(self, choices):
        for choice in choices:
            if isinstance(choice, (list, tuple)):
                yield choice
            else:
                yield (choice, choice)

    def set_display(self, name, value):
        setattr(self, 'get_%s_display' % name.lower(), lambda: value)

    def __iter__(self):
        return iter(self._iter_choices)

    def __getattr__(self, attname):
        try:
            return self._reverse_dict[attname]
        except KeyError:
            raise AttributeError(attname)

    def __getitem__(self, key):
        return self._choice_dict[key]

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__,
                           ', '.join(("'%s'" % i[1] for i in self._choices)))
    

class Choices(object):
    """
    A class to encapsulate handy functionality for lists of choices
    for a Django model field.

    Accepts verbose choice names as arguments, and automatically
    assigns numeric keys to them. When iterated over, behaves as the
    standard Django choices tuple of two-tuples.

    Attribute access allows conversion of verbose choice name to
    choice key, dictionary access the reverse.

    Example:

    >>> STATUS = Choices('DRAFT', 'PUBLISHED')
    >>> STATUS.draft
    DRAFT
    >>> STATUS[1]
    'PUBLISHED'
    >>> tuple(STATUS)
    (('DRAFT', 'DRAFT'), ('PUBLISHED', 'PUBLISHED'))

    >>> STATUS = Choices(('DRAFT', 'is a draft'), ('PUBLISHED', 'is published'))
    >>> STATUS.draft
    DRAFT
    >>> tuple(STATUS)
    (('DRAFT', 'is a draft'), ('PUBLISHED', 'is published'))

    """

    def __init__(self, *choices):
        self._choices = tuple(self.equalize(choices))
        self._choice_dict = dict(self._choices)
        self._reverse_dict = dict(((i[0].lower(), i[0]) for i in self._choices))

    def equalize(self, choices):
        for choice in choices:
            if isinstance(choice, (list, tuple)):
                yield choice
            else:
                yield (choice, choice)

    def __iter__(self):
        return iter(self._choices)

    def __getattr__(self, attname):
        try:
            return self._reverse_dict[attname]
        except KeyError:
            raise AttributeError(attname)

    def __getitem__(self, key):
        return self._choices[key][0]

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__,
                          ', '.join(("'%s'" % i[0] for i in self._choices)))