Enum JsonValue 

pub enum JsonValue {
    Null,
    Boolean(bool),
    Number(f64),
    String(String),
    Array(Vec<JsonValue>),
    Object(BTreeMap<String, JsonValue>),
    // some variants omitted
}

An in-memory JSON value.

This is the currency of the FieldCodec trait: a codec produces a JsonValue when encoding and is handed one when decoding. The codec itself never deals with JSON syntax — serialising and parsing are handled by this crate.

use capnp_json::JsonValue;

let value = JsonValue::Array(vec![
  JsonValue::String("hello".into()),
  JsonValue::Number(42.0),
  JsonValue::Null,
]);
assert_eq!(value, value.clone());

Numbers

Number is an f64, matching JSON’s own numeric model. A codec that needs the full 64-bit integer range should encode to String, which is what this crate does for Int64 and UInt64 fields.

Object ordering

Object is a BTreeMap, so its members are written in sorted key order. JSON objects are unordered by definition, so no order is more correct than another, but a deterministic one matters: the same value must encode to the same bytes every time, or golden-file tests, response caching and anything signing the output stop working. Sorted order is also the canonical form specified by RFC 8785.

Members of schema structs never pass through this map — they are written in schema declaration order — so this affects only the objects a custom FieldCodec builds.

Duplicate keys are rejected when parsing, so an Object decoded by this crate never loses a member.

Variants

Null

JSON null. Also the encoding of a Cap’n Proto Void.

Boolean(bool)

JSON true or false.

Number(f64)

A JSON number. See the note on numbers.

String(String)

A JSON string, already unescaped.

Array(Vec<JsonValue>)

A JSON array.

Object(BTreeMap<String, JsonValue>)

A JSON object. See the note on ordering.

Trait Implementations

impl Clone for JsonValue

fn clone(&self) -> JsonValue

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for JsonValue

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for JsonValue

fn eq(&self, other: &JsonValue) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for JsonValue