How to define integer tag in enum?

[lz1998]

https://serde.rs/enum-representations.html#adjacently-tagged

{"t": "Str", "c": "the string"} ➝ {"t": 1, "c": "the string"}
{"t": "Para", "c": [{...}, {...}]} ➝ {"t": 2, "c": [{...}, {...}]}

#[derive(Serialize, Deserialize)]
#[serde(tag = "t", content = "c")]
enum Block {
    Para(Vec<Inline>),
    Str(String),
}

[edgarogh]

Serde's enum variant serializers rely on strings¹ and there's no way around that without modifying serde_json² in your case. You will probably have to implement the (de)serialization of Block yourself if you really need this feature.

For instance, for Serialize :

impl Serialize for Block {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer
    {
        #[derive(Serialize)]
        #[serde(rename = "Block")]
        struct AdjTagged<T> {
            t: u8,
            c: T,
        }

        match self {
            Block::Para(field) => AdjTagged { t: 1, c: field }.serialize(serializer),
            Block::Str(field) => AdjTagged { t: 2, c: field }.serialize(serializer),
        }
    }
}

Footnotes

1. https://docs.rs/serde/latest/serde/trait.Serializer.html#tymethod.serialize_tuple_variant ↩

2. https://docs.rs/serde_json/1.0.85/src/serde_json/ser.rs.html#358-383 ↩

[kangalio]

Duplicate of #745

[Mingun]

While this is essentially a duplicate of #745, the latest changes from #2505 probably could solve the original problem