ponyc VS frank

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/

For the curious, "do be do be do" is a seminal paper in the literature on algebraic effects that introduces _frank_, quirky little language that has algebraic effects but not handlers, at least in the traditional sense.

Traditionally, an effect handler is an interpreter for a stream of commands, conforming to a specific interface. Generally, handlers surface in languages as a sort of generalized try/catch mechanism, that receive a "callback" to resume the "exception" that produced the command. In frank, not so.

Frank is based around the idea of _operators_, which generalize functions with the capability of interpreting multiple streams of commands. A plain function can be seen, in fact, as the special case of an operator that interprets no commands.

Operators are organized around ports and pegs. Pegs are the set of side effects that a computation needs. Each port is an offer to extend that set for downstream callers. Instead of building up a union of effects that each function needs, Frank propogated ambient ability inwards. Operators can then be composed based on the ports and pegs they offer.

operator: X → [peg]Y

This works partially because operators are shallow handlers and not deep handlers. Handlers interpret commands: if the handler itself is in scope when interpreting a command, then the language is said to have deep handlers. Frank has shallow handlers, meaning that commands are interpreted in an environment without the handling operator present. Shallow handlers give greater control to the programmer with respect to how commands are interpreted.

(This is a bad explanation because you already need to know what I'm talking about to understand what I'm talking about, but oh well.)

My one critism of frank is that the effect model is kinda hard for the working programmer to understand. I can explain Koka effects as "exceptions plus multiple resumption". I don't really have a categorical phrase for frank, and that's its innovation. This isn't so much a criticism but a plea for the pedagogical ramp to this research to improve.

do be do be do.

If you're still curious, check out the compiler github repo:

https://github.com/frank-lang/frank

And if anything is wrong in the above explanation, please correct me, because we all benefit from Cunningham's Law in the end. Allow me to be the fool.

How does this compare to other effect-oriented languages like Koka, Frank, and Eff?

I've been doing some work with Koka lately, but I briefly looked into the other three (including Effekt) and it mostly came down to, 'Koka seems most active in development'[1] and 'Koka had the easiest to use documentation for me'[2].

[1] E.g. https://github.com/effekt-lang/effekt had its last commit back in June; https://github.com/frank-lang/frank last commit last year; but https://github.com/koka-lang/koka last update was Oct 15. Effekt seems semi-active, at least, compared to Frank. While stability is good, I wouldn't expect it in a language actively being used for research.

[2] Comparing https://koka-lang.github.io/koka/doc/book.html and https://effekt-lang.org/docs/ and https://www.eff-lang.org/learn/

Frank's effect handling. "A strict functional programming language with a bidirectional effect type system designed from the ground up around a novel variant of Plotkin and Pretnar's effect handler abstraction. ... Frank [is different from other PLs with effect type systems in that it is based on] generalising the basic mechanism of functional abstraction itself. A function is simply the special case of a Frank operator that interprets no commands. Moreover, Frank's operators can be multihandlers which simultaneously interpret commands from several sources at once, without disturbing the direct style of functional programming with values. Effect typing in Frank employs a novel form of effect polymorphism which avoid mentioning effect variables in source code. This is achieved by propagating an ambient ability inwards, rather than accumulating unions of potential effects outwards."