Trait OpFieldModifier 

pub trait OpFieldModifier<T>:
    Send
    + Sync
    + 'static {
    // Required methods
    fn field_name(&self) -> &'static str;
    fn apply(&self, target: &mut T);
    fn diagnostic_value(&self) -> Value;
}

A conditional per-op modifier.

Modifiers are constructed only when the user actually bound the corresponding field in the Polydat scope — the chain pre-filters at build time, so anything reachable through ModifierChain::apply is by construction active. There is no is_active() method.

The target type T is the engine’s per-statement type (e.g. scylla::statement::Statement or cassandra_cpp::Statement). Each engine module provides its own impl OpFieldModifier<EngineStatement> for FooMod types that translate a captured Rust value into the engine’s setter call.

Required Methods

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

User-facing field name. Matches the op-template key and the adapter’s universal-field selector list. Returned as &'static str so trace sinks can keep cheap references.

fn apply(&self, target: &mut T)

Mutate the target with the captured value. Must not look anything up — all state needed for the mutation is already captured in the modifier struct’s fields.

fn diagnostic_value(&self) -> Value

Structured diagnostic representation of the captured value, used by ModifierTraceSink consumers. Called LAZILY — only when a sink is installed AND the sink decides to record this event.

Dyn Compatibility

This trait is dyn compatible.

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

Implementors