nx-value

NxValue: the value a Rust host passes to compiled NX and reads back from it.

It is a JSON-like tree (booleans, integers, floats, strings, lists and records with an optional type name) and it is the Rust form of an NX canonical value, so a host builds one and passes it as it is. JSON and MessagePack are encodings of it for a wire or a store, both through serde.

use nx_value::NxValue;

let value = NxValue::from_json_str(r#"{ "$type": "Point", "x": 1, "y": 2.5 }"#).unwrap();
let NxValue::Record { type_name, properties } = &value else { unreachable!() };
assert_eq!(type_name.as_deref(), Some("Point"));
assert_eq!(properties.get("x"), Some(&NxValue::Int(1)));
assert_eq!(value.to_json_string().unwrap(), r#"{"$type":"Point","x":1,"y":2.5}"#);

NX has no null: its absent value is the empty list, NxValue::empty(). NxValue::Null is the host's spelling of absence, which NX reads as the empty value and writes in the two places the canonical encoding spells null. Host values in docs/nx-ir-format.md defines the model.

To run compiled NX with these values, depend on nx-ir-runtime.

The crate is versioned with the NX release it ships in, and its API may change between minor versions while NX is 0.x. Depend on it at the same version as nx-ir-runtime.