algebraic lists, maps, and sets (jdk 23+)

Used some of the newer features of java to create short and (hopefully) efficient immutable collections. Specifically provides the following immutable structures:

• sorted map adt (VTreeMap) - implemented using the Arne-Andersson tree described in this paper by Prabhakar Ragde; this development also incorporates some bug fixes to the algorithms listed in the paper

  • the bugfixes and adjust fn specifically were from this formally verified Isabelle development

• list adt VList - a fairly standard immutable polymorphic list type modeled algebraically using sealed interfaces

• tree set adt VTreeSet - a polymorphic tree set that is implemented using the balanced Arne-Andersson tree mentioned

NOTE: This isn't so much a library as it is a collection of reusable half complete immutable data structures (that is far smaller scope and intent than vavr, e.g.). So don't rely on it for a huge production system. Requires jdk23+

Contains some unit tests and property tests (via jqwik). I expect additional methods will be added and tested in future versions. Good enough for now.