New submission from Daniel Urban <urban.dani...@gmail.com>: Currently instances of classes which inherit an ABC in collections.abc will have a __dict__. This can be a problem for example a tree-like data structure. It would make sense to inherit for example MutableMapping, but that would possibly mean, that every node in the tree would have a __dict__, which is probably a waste of memory.
A workaround for this problem is not inheriting the ABC, and using ABCMeta.register (and optionally adding the mixin methods explicitly), but this feels like a hack. The attached patch adds an empty __slots__ to the ABCs in collections.abc. I excluded the mapping views (MappingView, KeysView, ItemsView and ValuesView), because they can't have an empty __slots__, and I think using a nonempty __slots__ possibly can cause problems in some cases with multiple inheritance. ---------- components: Library (Lib) files: collections_abc_slots.diff keywords: patch messages: 129534 nosy: durban, rhettinger, stutzbach priority: normal severity: normal status: open title: Add empty __slots__ to collections.abc abstract base classes type: feature request versions: Python 3.3 Added file: http://bugs.python.org/file20910/collections_abc_slots.diff _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue11333> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
