Yams without Foundation?

[t089]

Yams without Foundation?

[jpsim]

ok that makes sense.

I hacked up a proof-of-concept to remove Foundation here: https://github.com/jpsim/Yams/compare/jp-no-foundation

It removes a ton of useful features from Yams, but it gets the following compiling without Foundation:

import Yams

let yaml = """
a: 0
b: 1.2
c: [1, 2, 3]
d:
  - a
  - b
  - c
"""

dump(try Yams.load(yaml: yaml)!)

And it builds and runs on Linux

$ docker run -it -v `pwd`:`pwd` -w `pwd` swift:latest swift run -c release
Building for production...
Build complete! (0.20s)
▿ 4 key/value pairs
  ▿ (2 elements)
    ▿ key: AnyHashable("a")
      - value: "a"
    - value: 0
  ▿ (2 elements)
    ▿ key: AnyHashable("d")
      - value: "d"
    ▿ value: 3 elements
      - "a"
      - "b"
      - "c"
  ▿ (2 elements)
    ▿ key: AnyHashable("b")
      - value: "b"
    - value: 1.2
  ▿ (2 elements)
    ▿ key: AnyHashable("c")
      - value: "c"
    ▿ value: 3 elements
      - 1
      - 2
      - 3

There are linker errors when passing --static-swift-stdlib though, so that would need to be sorted out.

But his demonstrates that the core functionality of Yams should be usable without the Foundation dependency.

[t089]

🤔 Bad timing, maybe there is something brewing at the fruit company.
https://twitter.com/ktosopl/status/1601145297077686272?s=46&t=C2w1wZhSOLAErfvayJ24KQ

[jpsim]

As an example, a simple "Hello World" Swift binary compiled with swift build -c release --static-swift-stdlib on swift:5.7.1 weighs in at 7.6M. Adding the Yams dependency increases the binary size to 50M.

Yikes, that's a pretty heavy dependency.

Why do you need the statically compile the Swift stdlib if you're running it on what appears to be a Docker image with Swift installed?

On macOS, a simple import Yams; print(try Yams.load(yaml: "a: 0")!) CLI executable is 920 KB when built for release for arm64.

[t089]

Why do you need the statically compile the Swift stdlib if you're running it on what appears to be a Docker image with Swift installed?

Usually, we build on docker swift:5.7 but then deploy on a distroless image which has no (swift) runtime dependencies pre-installed to make the final image as small as possible.

[t089]

Nice, that's already a great start. I think you also removed the entire Codable support, that seems like a big loss and sth we should look into maybe. I will check it out in more details as well.

[jpsim]

Nice, that's already a great start. I think you also removed the entire Codable support, that seems like a big loss and sth we should look into maybe. I will check it out in more details as well.

Yes, I removed most of what wasn't needed for my simple Yams.load(yaml:) demo. It's a proof-of-concept and not something meant to be seriously considered, I just wanted to show that the core Yams functionality doesn't strictly require Foundation.

[jpsim]

Re-added YAMLDecoder:

let bandYAML = """
members:
  - name: John Coltrane
    age: 27
  - name: Miles Davis
    age: 23
"""

struct Person: Codable {
    let name: String
    let age: Int
}

struct Band: Codable {
    let members: [Person]
}

let band = try YAMLDecoder().decode(Band.self, from: bandYAML)
dump(band)

$ docker run -it -v `pwd`:`pwd` -w `pwd` swift:latest swift run -c release
Building for production...
Build complete! (0.19s)
▿ 4 key/value pairs
  ▿ (2 elements)
    ▿ key: AnyHashable("b")
      - value: "b"
    - value: 1.2
  ▿ (2 elements)
    ▿ key: AnyHashable("d")
      - value: "d"
    ▿ value: 3 elements
      - "a"
      - "b"
      - "c"
  ▿ (2 elements)
    ▿ key: AnyHashable("a")
      - value: "a"
    - value: 0
  ▿ (2 elements)
    ▿ key: AnyHashable("c")
      - value: "c"
    ▿ value: 3 elements
      - 1
      - 2
      - 3
▿ yams_cli.Band
  ▿ members: 2 elements
    ▿ yams_cli.Person
      - name: "John Coltrane"
      - age: 27
    ▿ yams_cli.Person
      - name: "Miles Davis"
      - age: 23

[jpsim]

It's definitely possible to do this for real, not just as a proof-of-concept demo, it's just a matter of refactoring and time.

Also some questions around what to do for Foundation types. Should Date, UUID & Data just be parsed as String?

[t089]

It's definitely possible to do this for real, not just as a proof-of-concept demo, it's just a matter of refactoring and time.

That's really cool. I think it would be a great initiative.

Also some questions around what to do for Foundation types. Should Date, UUID & Data just be parsed as String?

Probably yes. The alternative to Data usually is a simple [UInt8].