Trait RowFn 

pub trait RowFn:
    'static
    + Sized
    + Clone
    + Send
    + Sync {
    type Options: 'static + Send + Sync + Clone + Debug + Display + PartialEq + Eq + Hash;

    const ARG_NAMES: &'static [&'static str];
    const INFALLIBLE: bool;

    // Required methods
    fn id(&self) -> ScalarFnId;
    fn dispatch<V: RowVisitor<Self::Options>>(
        &self,
        options: &Self::Options,
        args: &[DType],
        visitor: V,
    ) -> VortexResult<V::VisitResult>;

    // Provided methods
    fn serialize(
        &self,
        options: &Self::Options,
    ) -> VortexResult<Option<Vec<u8>>> { ... }
    fn deserialize(
        &self,
        _metadata: &[u8],
        _session: &VortexSession,
    ) -> VortexResult<Self::Options> { ... }
}

A strict scalar function whose row kernel cannot produce null from valid inputs.

This is stronger than ScalarFnVTable::is_strict, which requires null propagation but permits valid inputs to produce null. The framework derives output validity only from input validity.

A dispatched OutputElement or OutputSink describes the non-nullable values produced for valid rows. The framework widens that dtype when an input dtype is nullable, attaches the input-derived validity, and casts the finished array to the widened dtype. Implementations do not construct nullable placeholders for invalid rows.

Declare argument names and use dispatch to select element and output types. Every implementation receives the standard ScalarFnVTable. A public type that needs custom vtable hooks can delegate its row kernel through row_fn_return_dtype and execute_rows.

Required Associated Constants

const ARG_NAMES: &'static [&'static str]

The arguments in display order. Its length is the function’s exact arity.

const INFALLIBLE: bool

Whether every dispatch is infallible.

See ScalarFnVTable::is_infallible for a more detailed explanation of semantic errors.

The framework checks dispatched element and result types. A conservative false is allowed.

Required Associated Types

type Options: 'static + Send + Sync + Clone + Debug + Display + PartialEq + Eq + Hash

Options for this function, or EmptyOptions for none.

Required Methods

fn id(&self) -> ScalarFnId

Returns the ID of the scalar function.

fn dispatch<V: RowVisitor<Self::Options>>( &self, options: &Self::Options, args: &[DType], visitor: V, ) -> VortexResult<V::VisitResult>

Choose element types for these input dtypes and visit the framework with them.

Planning and execution both call this method, so its result must depend only on options and args. Cross-argument dtype validation belongs here.

Provided Methods

fn serialize(&self, options: &Self::Options) -> VortexResult<Option<Vec<u8>>>

Serialize this function’s options, or return None when the function is not serializable.

fn deserialize( &self, _metadata: &[u8], _session: &VortexSession, ) -> VortexResult<Self::Options>

Restore options written by serialize.

Dyn Compatibility

This trait is not dyn compatible.

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

Implementors