| import collections |
| |
| |
| # from jaraco.collections 3.3 |
| class FreezableDefaultDict(collections.defaultdict): |
| """ |
| Often it is desirable to prevent the mutation of |
| a default dict after its initial construction, such |
| as to prevent mutation during iteration. |
| |
| >>> dd = FreezableDefaultDict(list) |
| >>> dd[0].append('1') |
| >>> dd.freeze() |
| >>> dd[1] |
| [] |
| >>> len(dd) |
| 1 |
| """ |
| |
| def __missing__(self, key): |
| return getattr(self, '_frozen', super().__missing__)(key) |
| |
| def freeze(self): |
| self._frozen = lambda key: self.default_factory() |
| |
| |
| class Pair(collections.namedtuple('Pair', 'name value')): |
| @classmethod |
| def parse(cls, text): |
| return cls(*map(str.strip, text.split("=", 1))) |
