Trait Schema 

pub trait Schema {
    // Required method
    fn schema() -> DynamicSchema;
}

A type whose postcard wire shape is describable by a DynamicSchema.

Schema is implemented for every T: Document (via the M9 derive, see obj_derive::Document) and also for hand-written “historical” types that describe the wire shape of an older version of a Document. Historical types never need to be Documents themselves — they exist purely to describe bytes the current reader still has on disk.

Separating Schema from Document keeps the migration registry (#82) honest: a historical_schemas() entry refers to a Schema-only type that owns no collection name and has no Document::VERSION of its own (the (u32, ...) pair on the outside carries the version).

Power-of-ten posture

• Rule 9. No dyn; static dispatch via the associated function below.
• Rule 5. Implementations return a fresh DynamicSchema by value — pure data, no shared mutable state.

Required Methods

fn schema() -> DynamicSchema

Return the postcard wire-shape description for Self.

Implementations build the schema bottom-up from the variants in DynamicSchema. The derive (M10 #82) emits a Schema impl for every #[derive(Document)] type alongside the Document impl; hand-impls follow the same shape.

Dyn Compatibility

This trait is not dyn compatible.

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

Implementors