django-model-utils/model_utils/__init__.py
2010-01-12 21:47:28 -05:00

45 lines
1.3 KiB
Python

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'))
"""
def __init__(self, *choices):
self._choices = tuple(enumerate(choices))
self._choice_dict = dict(self._choices)
self._reverse_dict = dict(((i[1], i[0]) for i in self._choices))
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._choice_dict[key]
def __repr__(self):
return '%s(%s)' % (self.__class__.__name__,
', '.join(("'%s'" % i[1] for i in self._choices)))