1 unstable release
0.1.0 | Oct 29, 2023 |
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#1523 in Encoding
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16KB
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serde-constant
This crate provides a type that can represent a single-const serde value. For example, asserting that a particular bool is always true.
You can use this for disambiguation in serde(untagged)
structures, or just for validation.
Examples
use serde_constant::ConstBool;
#[derive(Deserialize)]
struct Foo {
bar: String,
baz: ConstBool<true>,
}
assert!(serde_json::from_value::<Foo>(json!({ "bar": "quux", "baz": true })).is_ok());
assert!(serde_json::from_value::<Foo>(json!({ "bar": "quux", "baz": false })).is_err());
use serde_constant::ConstI64;
// int tags? No problem!
#[derive(Deserialize)]
#[serde(untagged)]
enum Foo {
Bar {
tag: ConstI64<1>,
},
Baz {
tag: ConstI64<2>,
x: Option<String>,
},
}
assert!(matches!(
serde_json::from_value(json!({ "tag": 2, "x": null }))?,
// would have been Bar if `tag` were just `i64`
Foo::Baz { x: None, .. },
));
Dependencies
~110–340KB