swift-evolution VS KEEP

[A Vision for Embedded Swift](https://github.com/apple/swift-evolution/blob/main/visions/e...) has the details on this new build mode and is quite interesting.

> Effectively, there will be two bottom layers of Swift, and the lower one, “non-allocating” Embedded Swift, will necessarily be a more restricted compilation mode (e.g. classes will be disallowed as they fundamentally require heap allocations) and likely to be used only in very specialized use cases. “Allocating” Embedded Swift should allow classes and other language facilities that rely on the heap (e.g. indirect enums).

Also, this seems to maybe hint at the Swift runtime eventually being reimplemented in non-allocating Embedded Swift rather than the C++ (?) that it uses now:

> The Swift runtime APIs will be provided as an implementation that’s optimized for small codesize and will be available as a static library in the toolchain for common CPU architectures. Interestingly, it’s possible to write that implementation in “non-allocating” Baremetal Swift.

I may be out of my depth here as I've only casually used Rust, but this seems similar to Swift's proposed lifetime dependencies[1]. They're not in the type system formally so maybe they're closer to poloneius work

[1]: https://github.com/apple/swift-evolution/blob/3055becc53a3c3...

Swift recently adopted a region-based approach for safe concurrency that builds on Milano et al’s ideas: https://github.com/apple/swift-evolution/blob/main/proposals...

No, it's not. Refcounting CAN be a garbage collection algorithm, but in Swift it's deterministic and done at compile time. Not to mention recently added support for non-copyable types that enforces unique ownership: https://github.com/apple/swift-evolution/blob/main/proposals...

You can stackallocate buffers with unsafe Swift but it's not exactly fun to use. https://github.com/apple/swift-evolution/blob/main/proposals/0322-temporary-buffers.md

If the docs do not suffice, read the concurrency proposals of Swift Evolution. The authors describe the semantics in a very detailed way there.

`Either foo()` and `Foo foo() throws MyError` and are pretty much isomorphic.

https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/...

Nice. So for example, it looks like Kotlin has a nearly identical feature at the language level which will be optimizable when Valhalla ships: https://github.com/Kotlin/KEEP/blob/master/notes/value-class...

> In the future, in a Valhalla-capable JVM, JVM primitive classes will enable efficient representation of Kotlin value classes with an arbitrary number of underlying fields on JVM.

Most other languages agree that checked exceptions are not good by not having them.

As for alternatives, Try/Result and similar monads have decent adoption even in Java, but personally I quite like the Kotlin philosophy [1] to not have generic error containers and either use runtime exceptions or make failures of the return type.

[1] https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/...

If you want to read more and don't want to google it: https://github.com/Kotlin/KEEP/blob/data-objects/proposals/data-objects.md

Under the hood: https://github.com/Kotlin/KEEP/blob/master/proposals/coroutines.md .

you can check more here

You can use explicit API mode, then everything needs explicit visibility