verona

Fun fact: the person who created Pony, Sylvan Clebsch, has been working on a Microsoft Research project called Verona. From it's README [0]: > Project Verona is a research programming language to explore the concept of concurrent ownership. We are providing a new concurrency model that seamlessly integrates ownership. [0] https://github.com/microsoft/verona/tree/master

Microsoft's Verona language is an interesting point in this design space--it allows references to be scoped to arbitrary heap regions: https://github.com/microsoft/verona/blob/master/docs/explore.... You can have arbitrary aliasing within a region, but the type system ensures that inter-region references obey lifetime rules. In a language like Verona, ParsedFile could have a contents Vec allocated in the same region as the ParsedFile, and a words Vec containing references into the contents Vec. Reference-typed fields by default are constrained to the same region as the parent object, so the above example works straightforwardly. The downside of this is that, in the general case, you have to garbage collect the regions. You can partition the heap using regions but all the same problems apply to the partitioned heap. NB: Rust uses the term