Commit 2020-12-21 20:56 3b9cbdfe

feat(data/ordmap): Ordered maps (like rb_map but better) (#5353) This cleans up an old mathlib branch from 2 years ago, so it probably isn't in very modern style, but it would be best to get it merged and kept up to date rather than leaving it to rot. It is an implementation of size balanced ordered maps based on Haskell's Data.Map.Strict. The ordnode structure can be used directly if one is only interested in using it for programming purposes, and the ordset structure bundles the proofs so that you can prove theorems about inserting and deleting doing what you expect.