cxx-interop-test VS swift

Yes, it has been in the Swift compiler for some time now

The original flag was "-experimental-cxx-interop", now it is "-enable-cxx-interop"

See here for examples of it in use, including interop with the C++ std library types:

https://github.com/plotfi/cxx-interop-test

For a real-world example of using this, here's a test repo from the core developers:

  https://github.com/plotfi/cxx-interop-test

Because of C/C++ interop, and integration with CMake, you can just add Swift to a Zephyr project and it pretty much Just Works. [The docs](https://github.com/apple/swift/blob/main/docs/EmbeddedSwift/...) should mostly apply to the Zephyr SDK as well.

Fortunately, the Observation framework is part of the Swift 5.9 standard library. We can learn more information by examining its source code.

They do! See https://github.com/apple/swift/blob/main/docs/LibraryEvoluti...

You can also see an example of what a different high level language integration with Swift ABI looks like here: https://github.com/dotnet/designs/blob/main/proposed/swift-i...

So is differentiable Swift a package for Swift or is it part of the Swift standard library? The video says go to swift.org but I can't find any info about differentiable Swift on that site.

Swift's Differentiable Programming Manifesto. Swift has a powerful differentiable programming component, integrated with the compiler.

You can do the same thing the other way around - https://github.com/apple/swift/blob/main/docs/Android.md.

Codable (along with other derived conformances like Equatable, Hashable, and RawRepresentable) is indeed built in to the compiler[0], but unlike Serde, it operates during type-checking on a fully-constructed AST (with access to type information), manipulating the AST to insert code. Because it operates at a later stage of compilation and at a much higher level (with access to type information), the work necessary is significantly less.

With ongoing work for Swift macros, it may eventually be possible to rip this code out of the compiler and rewrite it as a macro, though it would need to be a semantic macro[1] rather a syntactic one, which isn't currently possible in Swift[2].

[0] https://github.com/apple/swift/blob/main/lib/Sema/DerivedCon...

`Int` is a regular struct with a single stored property of type `Builtin.Word` . But the latter is a magical compiler built-in. Source for integer types is generated from this template - https://github.com/apple/swift/blob/9da65ca0a15fdf341649c994b0a77ec3b71f2687/stdlib/public/core/IntegerTypes.swift.gyb