#derive #lightweight #framework

macro sval_derive

Custom derive for sval

2 releases

0.0.1 Dec 3, 2018
0.0.0 Dec 3, 2018
Download history 7/week @ 2018-12-03

2 downloads per month
Used in 1 crate

Apache-2.0 OR MIT

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Build Status Latest version Documentation Latest Documentation Master

A prototype, lightweight, no-std, object-safe, serialization-only API for structured values with serde support.

Producers of structured values use the value module. Consumers of structured values use the stream module. sval offers a json-like data model, which is more limiting than serde's, but capable enough to represent Rust datastructures in one form or another.

This library is designed to plug a no-std-object-safe sized hole in Rust's current serialization ecosystem. The driving use-case is structured logging, where individual events are typically small, and there's no complete schema that can tie values in any one event to values in another.

sval_json and sval_derive are mostly pilfered from dtolnay's excellent miniserde project.

Minimum rustc

This library requires Rust 1.31.0, which is currently in beta.

See also

How to use it

Add sval to your crate dependencies:

version = "0.0.4"

To support my datastructures

Simple struct-like datastructures can derive sval::Value:

features = ["derive"]
extern crate sval;

struct MyData {
    id: u64,
    name: String,

Other datastructures can implement sval::Value manually:

use sval::value::{self, Value};

struct MyId(u64);

impl Value for MyId {
    fn stream(&self, stream: &mut value::Stream) -> Result<(), value::Error> {

To format my data

The sval_json crate can format any sval::Value as json:

version = "0.0.4"
let my_json = sval_json::to_string(my_data)?;

To integrate with serde

sval has out-of-the-box serde integration between sval::Values and serde::Serializes. Add the serde feature to sval to enable it:

features = ["serde"]

Then convert between serde and sval:

let my_serialize = sval::serde::to_serialize(my_data);


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