Crate netidx_value

Expand description

Universal value type for netidx pub/sub.

This crate provides Value, a dynamically-typed enum that can represent any data type publishable in netidx. Values support 25+ built-in types including integers, floats, strings, bytes, arrays, maps, decimals, timestamps, and durations.

§Key Features

Rich type system: Integers (with LEB128 varint encoding), floats, strings, bytes, arrays, maps, decimals, timestamps, durations
Efficient cloning: Small values (≤64 bits) are bitwise copied; larger values use reference counting
User-defined types: Register custom types with the Abstract wrapper
Wire-efficient: Compact binary encoding via Pack
Parsing & printing: Parse from strings, format for display

§Example

use netidx_value::Value;

let v = Value::I64(42);
assert_eq!(v.clone().cast_to::<f64>()?, 42.0);

let s = Value::String("hello".into());
let arr = Value::Array(vec![v, s].into());

§User-Defined Types

You can register your own types using the abstract type system. Each type needs a unique UUID and must implement Pack, Debug, Hash, Eq, and Ord:

use netidx_value::{Value, Abstract};
use netidx_core::pack::Pack;
use netidx_derive::Pack;
use uuid::uuid;
#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Pack)]
struct Custom {
    field1: u32,
    field2: String,
}

// Register with a unique UUID (generate once, hardcode in your program)
const CUSTOM_TYPE_ID: uuid::Uuid = uuid!("550e8400-e29b-41d4-a716-446655440000");

let wrapper = Abstract::register::<Custom>(CUSTOM_TYPE_ID)?;
let t = Custom { field1: 42, field2: "test".into() };
let abstract_value: Value = wrapper.wrap(t).into();

// Later, downcast back to your type
if let Some(t) = abstract_value.downcast_ref::<Custom>() {
    println!("field1: {}", t.field1);
}

§Type Casting

Values support casting between compatible types using Value::cast_to(). For example, integers can be cast to floats, and vice versa (with range checking).