Enums with custom types

[RandyMarsh1]

Is it possible to have Enum variants that take a self named struct parameter and output as types?

#[tsync]
enum Message {
    MyStruct1(MyStruct1),
    MyStruct2(MyStruct2),
}

The ideal output: type Message = | MyStruct1 | MyStruct2; where the structs are types, not strings

.

This would allow easy structuring of JSON in Rust and Destructing in TypeScript, Example:

#[tsync]
#[derive(Serialize)]
struct MyStruct1 {
    data1: bool,
    data2: MyStruct2,
}

#[tsync]
#[derive(Serialize)]
struct MyStruct2 {
    data1: String,
    data2: i32,
}

#[tsync]
#[derive(Serialize)]
enum Message {
    MyStruct1(MyStruct1),
    MyStruct2(MyStruct2),
}

fn main() {
    let message = Message::MyStruct2(MyStruct2 {
        data1: "hello".to_string(),
        data2: 42,
    });

    let json = serde_json::to_string(&message).unwrap();
    println!("Send to frontend: {}", json);
    // Output: {"MyStruct2":{"data1":"hello","data2":42}}
}

[Wulf]

hey @RandyMarsh1, thanks for reporting this :)

Let me know if 1.7.0 doesn't work for you. I think eventually what we'll want to do is namespace a lot of this output. Closing this for now, feel free to re-open it

[RandyMarsh1]

Thanks, nested structs within structs now works, this is a great improvement 👍

However the specific scenario I was hoping for was Rust Enums that take a struct of the same name as input parameter like this:

#[tsync]
#[derive(Serialize)]
enum Message {
    MyStruct1(MyStruct1), <-- enum variant name == struct name
    MyStruct2(MyStruct2),
}

This currently does not output anything and is skipped.

The following does output a type but the variants are Strings, not Interfaces.

#[tsync]
#[derive(Serialize)]
enum Message2 {
    MyStruct1,
    MyStruct2,
}

This admittable requires a somewhat opinionated structure but I think is a nice clean way of generating JSON with the Enum variant as key and Struct as Value. The Example code in original post should compile and demonstrates the use case.

[Wulf]

Ah that should be possible too -- do you mind lending me a hand with this one?

• Update fn make_externally_tagged_variant(..) here to output the type separately and use the identifier, similar to the approach used in 1.7.0 Named enum variants (#25) #26.
• Run ./test/enum/tsync.sh and see if the ./test/enum/typescript.d.ts file changes appropriately