pub trait WindowUDFImpl: Debug + Send + Sync {

    /// Invoke the function, returning the [`PartitionEvaluator`] instance
    fn partition_evaluator(
        &self,
        partition_evaluator_args: PartitionEvaluatorArgs,
    ) -> Result<Box<dyn PartitionEvaluator>>;

}

/// Defines the state of the user-defined window function during
/// physical execution.
#[derive(Debug, Default)]
pub struct PartitionEvaluatorArgs<'a> {
    /// The expressions passed as arguments to the user-defined window
    /// function.
    input_exprs: &'a [Arc<dyn PhysicalExpr>],
    /// The corresponding data types of expressions passed as arguments
    /// to the user-defined window function.
    input_types: &'a [DataType],
    /// Set to `true` if the user-defined window function is reversed.
    is_reversed: bool,
    /// Set to `true` if `IGNORE NULLS` is specified.
    ignore_nulls: bool,
}