Struct DeclaredAggregateFn 

pub struct DeclaredAggregateFn { /* private fields */ }

A Cypher-declared aggregate function.

Holds three pre-parsed Expr bodies (init, update, finalize), the positional argument names of the update body, the declared return type, and a precomputed AggSignature.

Implementations

impl DeclaredAggregateFn

pub fn new( init_expr: Expr, update_expr: Expr, finalize_expr: Expr, arg_names: Vec<String>, return_dt: DataType, ) -> Self

Construct a declared aggregate from pre-parsed Cypher bodies.

pub fn build_signature(returns: DataType, arg_names: &[String]) -> AggSignature

Build a default AggSignature for a declared aggregate.

All update args are declared Utf8 (the M9 declared-scalar convention — promotions happen at row-decode time). The returned signature disables partial aggregation: state_fields is empty and supports_partial = false.

pub fn return_dt(&self) -> &DataType

The configured return DataType.

Trait Implementations

impl AggregatePluginFn for DeclaredAggregateFn

fn signature(&self) -> &AggSignature

Static signature.

fn create_accumulator(&self) -> Box<dyn PluginAccumulator>

Construct a fresh per-group accumulator.

impl Debug for DeclaredAggregateFn

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.