docs: add alternatives

This commit is contained in:
bytedream 2025-04-11 20:42:14 +02:00
parent 0a12ee6b3f
commit baeb1969fe

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@ -15,6 +15,9 @@ struct Test {
}
fn value_default() -> u32 { 42 }
// let test: Test = serde_json::from_value(json!({})).unwrap();
// -> Test { value: 42 }
```
That can get quiet messy if you have many fields with many (different) default values.
@ -28,11 +31,62 @@ struct Test {
#[serde_inline_default(42)]
value: u32
}
// let test: Test = serde_json::from_value(json!({})).unwrap();
// -> Test { value: 42 }
```
Internally, `#[serde_inline_default(...)]` gets expanded to a function which returns the set value and the attribute is replaced with `#[serde(default = "<function name>")]`.
So this macro is just some syntax sugar for you, but can get quiet handy if you want to keep your code clean or write declarative macros / `macro_rules!`.
## Alternatives
This crate isn't perfect. Thus, you might be more satisfied with alternatives `serde` provides.
With `#[serde(default)]` + `impl Default` on a struct, `serde` uses the default implementation of the struct to get default values for each field ([docs](https://serde.rs/container-attrs.html#default)):
```rust
#[derive(Deserialize)]
#[serde(default)]
struct Test {
value: u32
}
impl Default for Test {
fn default() -> Self {
Self {
value: 42
}
}
}
// let test: Test = serde_json::from_value(json!({})).unwrap();
// -> Test { value: 42 }
```
If you still need/want `serde-inline-default` features, you also can combine them with `#[serde(default))` and `impl Default`:
```rust
#[serde_inline_default]
#[derive(Deserialize)]
#[serde(default)]
struct Test {
value: u32,
#[serde_inline_default(0)]
other_value: u32,
}
impl Default for Test {
fn default() -> Self {
Self {
value: 42,
other_value: 42
}
}
}
// let test: Test = serde_json::from_value(json!({})).unwrap();
// -> Test { value: 42, other_value: 0 }
```
## License
This project is licensed under either of the following licenses, at your option: