Interface Opaque

cel/src/objects.rs:386–403

Trait for user-defined opaque values stored inside [`Value::Opaque`]. Implement this trait for types that should participate in CEL evaluation as opaque/user-defined values. An opaque value: - must report a stable runtime type name via [`Opaque::runtime_type_name`]; - participates in equality via the blanket [`OpaqueEq`] implementation; - can be formatted via [`AsDebug`]; - must be thread-safe (`

/// assert_eq!(a, b);
/// ```
pub trait Opaque: Any + OpaqueEq + AsDebug + Send + Sync {
    /// Returns a stable, fully-qualified type name for this value's runtime type.
    ///
    /// This name is used to check type compatibility before attempting downcasts
    /// during equality checks and other operations. It should be stable across
    /// versions and unique within your application or library (e.g., a package
    /// qualified name like `my.pkg.Type`).
    fn runtime_type_name(&self) -> &str;

    /// Optional JSON representation (requires the `json` feature).
    ///
    /// The default implementation returns `None`, indicating that the value
    /// cannot be represented as JSON.
    #[cfg(feature = "json")]
    fn json(&self) -> Option<serde_json::Value> {
        None
    }
}

impl dyn Opaque {
    pub fn downcast_ref<T: Any>(&self) -> Option<&T> {