#serialization #no_std

no-std sval

A no-std, object-safe serialization framework

9 releases

✓ Uses Rust 2018 edition

0.1.2 Jan 23, 2019
0.1.1 Jan 17, 2019
0.0.5 Jan 10, 2019
0.0.4 Dec 6, 2018

#85 in No standard library

Download history 43/week @ 2018-12-06 22/week @ 2018-12-13 9/week @ 2018-12-20 41/week @ 2018-12-27 23/week @ 2019-01-10 28/week @ 2019-01-17 27/week @ 2019-01-24

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Used in 1 crate

Apache-2.0 OR MIT

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Build Status Latest version Documentation Latest Documentation Master

A 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.

See also

Crate features

  • std: assume std is available and add support for std types.
  • derive: add support for #[derive(Value)].
  • serde: enable integration with serde.
  • arbitrary-depth: support stateful values with any depth.
  • test: add helpers for testing implementations of Value.

How to use it

Add sval to your crate dependencies:

version = "0.1.2"

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 = "0.1.2"
features = ["std"]
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"]

Use the to_serialize function to turn any sval::Value into a serde::Serialize:

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

Use the to_value function to turn any serde::Serialize into a sval::Value:

let my_value = sval::serde::to_value(my_data);