On Sun, Sep 21, 2014, at 01:18, David Wilson wrote:
Coming from this perspective, I'd prefer that further additions were limited to clean and far better understood structures. In this light, could we perhaps instead discuss the merits of a collections.Tree, collections.SortedDict or similar?
As I understand it, the problem with a tree, SortedDict/SortedSet, or in general any collection that relies on comparison relationships (heap, etc), is: unlike hashing (where Hashable implies an immutable hash relationship), there is no way to detect whether an object implements an immutable well-defined ordering. And that, unlike a mutable hashed object (which can AIUI only lose itself), a mutable sorted object (or a badly-behaved one like NaN) can cause other objects in the set to be inserted in the wrong place or not found.