this post was submitted on 14 Jan 2025
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I'm making a language with a lot of inspiration from rust and was experimenting with alternative enum syntax. It relies on literals to be types in order to convey information on the different options.

I don't really get on well with Typescript but having the ability to use literals as types is something I really liked as a lot of the times I use static string literals as errors. and having all the variants upcast through types makes it easier to do pattern matching.

Plain-text transcription of the image:

// using rust like enum syntax
Option<T> (
  | "Some" T
  | "None"
)

fn match_demo() {
  let some_option = Option "Some" "text";
  let none_option = Option "None";

  match some_option {
    "Some" "hello" => print("oh hi there"),
    "Some" text => print("Option is {text}"),
    "None" => print("Option is {text}"),
  }
}

// Or maybe more experimental syntax
Option<T> (
  | T
  | ()
)

fn match_demo2() {
  let opt = Option "something";
  match opt {
    "text" => "matching directly",
    var => "bind to variable",
    () => "nothing",
  }
}
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[–] calcopiritus@lemmy.world 14 points 1 day ago

I hate both of them. The first one is very clunky with all the ". The second one is not self-docummenting at all, and it makes some enums impossible.

For example, you can't represent:

enum A {
    B(u32)
    C(u32)
    D
}

It would be

A {
    | u32
    | u32
    | ()
}

Also, the pipe is very awkward to type, specially depending on keyboard layout. Since it's a rare character. If you need to separate between enums and struts and really don't want to use the enum and struct keywords, you can use different delimiters, like:

A [
 u32,
 u32
]

B {
 u32,
 u32
}