This crate provides two macros for generating a serde Serialize and
Deserialize implementation for enums.
These are SerializeWithDiscriminant and DeserializeWithDiscriminant
The implementations serializes and deserializes an enum as a struct with the discriminant as the first field and the variant fields as the following fields.
The Deserialize implementation expects the deserializer to call
visit_seq for structs, this is mainly because the deserializers I was
targeting do things this way. visit_map could be implemented but there is a
caveat here which is that this strategy would only work if the map being
deserialized always has the discriminant as the first entry.
Here are some examples
This enum will be serialized / deserialized as a u32
Rust
#[derive(DeserializeWithDiscriminant, SerializeWithDiscriminant, Debug, PartialEq)]
#[repr(u32)]
enum Foo {
A = 1,
B = 2,
C = 3,
}
It also supports enums with fields
This enum will first serialize / deserialize its discriminant value (a u16) then any fields
Rust
#[derive(DeserializeWithDiscriminant, SerializeWithDiscriminant, Debug, PartialEq)]
#[repr(u16)]
enum Bar {
A(String) = 1,
B {
a: i32,
b: u32,
} = 12,
C(i32, u64) = 7,
#[serde(other)]
D = 9,
}
serde attributesother this makes it so any unknown discriminant deserializes as this given
variant