Trait Precompile 

pub trait Precompile: Send + Sync {
    // Required methods
    fn name(&self) -> &'static str;
    fn id(&self) -> Felt;
    fn decode(&self, args: [Felt; 3]) -> Option<NodeType>;
    fn evaluate(
        &self,
        args: [Felt; 3],
        payload: &Payload,
        context: &mut DeferredContext<'_>,
    ) -> Result<Node, PrecompileError>;

    // Provided method
    fn init(&self) -> Vec<Node> { ... }
}

Semantic module installed in a PrecompileRegistry.

Each precompile owns one stable id and interprets that id’s three local tag felts.

Required Methods

fn name(&self) -> &'static str

Stable name hashed into the precompile id; renaming changes every tag this precompile owns.

fn id(&self) -> Felt

Stable tag id for this precompile.

The registry validates this against precompile_id and rejects framework-reserved ids, turning id drift into a setup-time failure.

fn decode(&self, args: [Felt; 3]) -> Option<NodeType>

Declares the body shape for recognized local tag arguments.

Returning None rejects the tag. The registry has already matched the precompile id, so this only interprets the tag’s local arguments.

fn evaluate( &self, args: [Felt; 3], payload: &Payload, context: &mut DeferredContext<'_>, ) -> Result<Node, PrecompileError>

Evaluates one owned node to its canonical form.

The registry has already matched the tag id; implementors receive only local args and a payload whose outer shape passed Self::decode. Use DeferredContext to evaluate registered child digests (digests present in the state’s node store) or to register helper nodes referenced by a compound canonical.

Common conventions:

• canonical values return themselves after validating payload contents;
• producing ops evaluate structural children and return the resulting canonical node;
• predicates return Node::TRUE on success and PrecompileError::AssertionFailed on mismatch;
• multi-chunk data nodes usually evaluate to a single-chunk value.

Provided Methods

fn init(&self) -> Vec<Node>

Canonical constants this precompile wants registered before execution.

State initialization loads every installed precompile’s init nodes into one bootstrap set, then evaluates each init node to ensure the set resolves under the installed registry. The default contributes no constants.

Dyn Compatibility

This trait is dyn compatible.

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

Implementors