Jsony

An experimental fast compiling serialization and deserialization rust library for JSON like formats.

WARNING: Jsony is currently in early development and makes extensive use of unsafe.

Features

• Fast compile times
• Competitive runtime performance
• Featureful derive macros for implementing To/From for various data formats
• Encoding checked at compile time, infallible at runtime
• Data formats
  • JSON (optional extension: trailing commas, comments, unquoted keys)
  • Custom Binary Encoding
• Lazy JSON parser for efficiently extracting small fragments.
• JSON templating macros
• Encode directly to a file or stack allocated to buffer.

Example

use jsony::Jsony;

#[derive(Jsony, Debug)]
#[jsony(FromJson, ToJson, tag = "kind")]
enum Status<'a> {
    Online,
    Error {
        #[jsony(default = i64::MAX)]
        code: i64,
        message: Cow<'a, str>,
        #[jsony(flatten, via = Iterator)]
        properties: Vec<(String, JsonItem<'a>)>,
    },
    Offline,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let input: String = jsony::object! {
        kind: "Error",
        code: 300,
        message: "System Failure",
        data: [1, 2, 3],
        value: {
          previous: {
            kind: "Offline",
          }
        }
    };

    let previous: Status = jsony::drill(&input)["value"]["previous"].parse()?;
    assert!(matches!(previous, Status::Offline));

    let status: Status = jsony::from_json(&input)?;

    assert_eq!(
      input,
      jsony::to_json(&status)
    );

    Ok(())
}

Acknowledgements

The derive feature set is largely based of serde and serde_with.
The json parser is heavily inspire by jiter and serde_json.