Terry Reedy <tjre...@udel.edu>: > Others have answered as to why other special-purpose > constrained-structure trees have not been added to the stdlib.
Ordered O(log n) mappings are not special-purpose data structures. I'd say strings and floats are much more special-purpose than ordered mappings, and yet Python has direct support for those. As I said, I use ordered mappings to implement timers. GvR uses the heapq module for the purpose. The downside of heapq is that canceled timers often flood the heapq structure; in networking you can easily start a thousand timers a second but virtually no timer ever expires. Python's asyncio ignores the problem, but GvR mentioned a periodic "garbage collection" as a potentially effective solution. I tested the garbage collection trick and it did seem very effective. Marko -- https://mail.python.org/mailman/listinfo/python-list
