ponyc VS verona

For example, the actor's model is not used by a lot of languages, Pony (https://www.ponylang.io/) and Elixir are the only ones that I know, but they address the concurrency problem quite well, while it's a pain to deal with in other languages at large scale.

And that last point is critical. If the language flatly can't represent some concepts it uses, they have to be implemented somewhere else. I had a similar discussion with a proponent for Pony once- the language itself is 100% safe, and fully dependent on C for its runtime and data structures. One of Rust's core strengths is being able to express unsafe concepts, meaning the unsafe code can expose a safe interface that accurately describes its requirements rather than an opaque C ABI. Vale doesn't seem to do that.

"Exterior iteration. Iteration used to be by stack / non-escaping coroutines, which we also called "interior" iteration, as opposed to "exterior" iteration by pointer-like things that live in variables you advance. Such coroutines are now finally supported by LLVM (they weren't at the time) and are actually a fairly old and reliable mechanism for a linking-friendly, not-having-to-inline-tons-of-library-code abstraction for iteration. They're in, like, BLISS and Modula-2 and such. Really normal thing to have, early Rust had them, and they got ripped out for a bunch of reasons that, again, mostly just form "an argument I lost" rather than anything I disagree with today. I wish Rust still had them. Maybe someday it will!"

I remember that one. The change was shortly after I started fooling with Rust and was major. Major as in it broke all the code that I'd written to that point.

"Async/await. I wanted a standard green-thread runtime with growable stacks -- essentially just "coroutines that escape, when you need them too"."

I remember that one, too; it was one of the things that drew me to the language---I was imagining something more like Pony (https://www.ponylang.io/).

"The Rust I Wanted probably had no future, or at least not one anywhere near as good as The Rust We Got."

Almost certainly true. But The Rust We Got is A Better C++, which was never appealing to me because I never liked C++ anyway.

Pony or bust.

If you have a value in mutable storage, and want to treat it as an immutable parameter without copying it first, you will need to provide some way to guarantee that it won't be mutated while being treated as immutable! There doesn't seem to be a definitive best way to do that (although the likes of Pony make a try at it).

The love child of Erlang and Rust exists already: Pony.

https://www.ponylang.io

It really is the best of both languages... unfortunately, the main supporter of Pony seems to have stopped using it in favour of Rust though :D.

But if that's really what you want, Pony is your language. It definitely deserves more love.

You can actually try to have a magic language which "does not ignore decades of PL research" but you are likely to get either something broken or a project that is likely not going to release in our lifetime.

Never a bad time to plug Pony lang[1] - a safety-oriented actor-model language. In addition to the numerous safety guarantees, you also get a beautiful syntax and automatic memory management. Really a great language that often gets overshadowed by Rust's hype-turfing.

[1]: https://www.ponylang.io/

According to this FAQ, snmalloc was designed for the Verona language:

https://microsoft.github.io/verona/faq.html

Unfortunately, I cannot find any significant code samples for Verona on the website or in the GitHub repo. There are a few types defined in a pretty low-level way:

https://github.com/microsoft/verona/tree/master/std/builtin

I think the future lies in figuring out how to get the benefits of that secret sauce, while mitigating or avoiding the downsides.

Like Boats said, the borrow checker works really well with data, but not so well with resources. I'd also add that it works well with data transformation, but struggles with abstraction, both the good and bad kind. It works well with tree-shaped data, but struggles with programs where the data has more intra-relationships.

So if we can design some paradigms that can harness Rust's borrow checker's benefits without its drawbacks, that could be pretty stellar. Some promising directions off the top of my head:

* Vale-style "region borrowing" [0] layered on top of a more flexible mutably-aliasing model, either involving single-threaded RC (like in Nim) generational references (like in Vale).

* Forty2 [1] or Verona [2] isolation, which let us choose between arenas and GC for isolated subgraphs. Combining that with some annotations could be a real home run. I think Cone [3] was going in this direction for a while.

* Val's simplified borrowing (mutable value semantics) combined with some form of mutable aliasing (this might sound familiar).

[0] https://verdagon.dev/blog/zero-cost-borrowing-regions-part-1... (am author)

[1] http://forty2.is/

[2] https://github.com/microsoft/verona

[3] https://cone.jondgoodwin.com/

Their approach lines up pretty well with how we do regions in Vale. [0]

Specifically, we consider the "spine" of a linked list to be in a separate "region" than the elements. This lets us freeze the spine, while keeping the elements mutable.

This mechanism is particularly promising because it likely means one can iterate over a collection with zero run-time overhead, without the normal restrictions of a more traditional Rust/Cyclone-like borrow checker. We'll know for sure when we finish part 3 (one-way isolation [1]); part 1 landed in the experimental branch only a few weeks ago.

The main difference between Vale and the paper's approach is that Vale doesn't assume that all elements are self-isolated fields, Vale allows references between elements and even references to the outside world. However, this does mean that Vale sometimes needs "region annotations", whereas the paper's system doesn't need any annotations at all, and that's a real strength of their method.

Other languages are experimenting with regions too, such as Forty2 [2] and Verona [3] though they're leaning more towards a garbage-collection-based approach.

Pretty exciting time for languages!

[0] https://verdagon.dev/blog/zero-cost-borrowing-regions-overvi...

[1] https://verdagon.dev/blog/zero-cost-borrowing-regions-part-3...

[2] http://forty2.is/

[3] https://github.com/microsoft/verona

Does this count? https://microsoft.github.io/verona/

What about new Rust that "Microsoft Research" trying to "explore" https://github.com/microsoft/verona/blob/master/docs/explore.md ?

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.

https://github.com/microsoft/verona/tree/master