Trait ConfigShape 

pub trait ConfigShape: Sized {
    // Required methods
    fn schema() -> Schema;
    fn to_value(&self) -> Value;
    fn from_value(value: &Value) -> Result<Self, ShapeError>;
}

A type that can describe its own configuration shape and move through it.

Implemented by #[derive(ConfigShape)] for structs, and by hand for the primitives and containers below. The three methods have to agree: to_value must produce something schema accepts, and from_value must invert to_value. A type where they disagree is a silently lossy option, which is the failure the SDK’s own round-trip test exists to catch.

Provided impls: bool, i64, String, Vec<T> and Option<T> (the last meaning “not required” at field position — see its impl). The derive supports structs with named fields (→ Schema::Record) and all-unit enums (→ Schema::Enum); tuple structs, data-carrying enums and unions are compile errors. The derive is re-exported at the crate root as lattice_plugin_sdk::ConfigShape, beside this trait’s path in shape.

Examples

use lattice_plugin_sdk::ConfigShape;
use lattice_plugin_sdk::shape::{ConfigShape as _, Schema, Value};

/// How a capture is filed.
#[derive(Debug, PartialEq, ConfigShape)]
enum Disposition { Append, FileUnder }

assert_eq!(
    Disposition::schema(),
    Schema::Enum(vec!["append".into(), "file-under".into()]),
);
assert_eq!(
    Disposition::from_value(&Value::Str("file-under".into())),
    Ok(Disposition::FileUnder),
);
assert!(Disposition::from_value(&Value::Str("sideways".into())).is_err());

Required Methods

fn schema() -> Schema

The declared shape, as sent to the host when the option is registered.

fn to_value(&self) -> Value

This value as a tree the host can validate against schema. Must always be accepted by it.

fn from_value(value: &Value) -> Result<Self, ShapeError>

Read a value back; the inverse of to_value.

Errors

A ShapeError carrying the path to the offending node when a kind is wrong, a required field is missing, or an enum string names no variant.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl ConfigShape for String

fn schema() -> Schema

fn to_value(&self) -> Value

fn from_value(value: &Value) -> Result<Self, ShapeError>

impl ConfigShape for bool

fn schema() -> Schema

fn to_value(&self) -> Value

fn from_value(value: &Value) -> Result<Self, ShapeError>

impl ConfigShape for i64

fn schema() -> Schema

fn to_value(&self) -> Value

fn from_value(value: &Value) -> Result<Self, ShapeError>

impl<T: ConfigShape> ConfigShape for Option<T>

Option<T> is how a field says it is not required.

The schema of an Option<T> is T’s — optionality is a property of the FIELD, not of the value, which is why Field::required carries it and this impl does not wrap the schema in anything. A bare Option<T> used as a whole option’s type therefore describes itself as T; None is then indistinguishable from absent, which is the correct reading at a leaf and the reason the derive only consults this at field position.

fn schema() -> Schema

fn to_value(&self) -> Value

fn from_value(value: &Value) -> Result<Self, ShapeError>

impl<T: ConfigShape> ConfigShape for Vec<T>

fn schema() -> Schema

fn to_value(&self) -> Value

fn from_value(value: &Value) -> Result<Self, ShapeError>

Implementors