Method reverse_udf

datafusion/expr/src/udaf.rs:294–296

Reserves the `AggregateUDF` (e.g. returns the `AggregateUDF` that will generate same result with this `AggregateUDF` when iterated in reverse order, and `None` if there is no such `AggregateUDF`).

(&self)

    /// generate same result with this `AggregateUDF` when iterated in reverse
    /// order, and `None` if there is no such `AggregateUDF`).
    pub fn reverse_udf(&self) -> ReversedUDAF {
        self.inner.reverse_expr()
    }

    /// Returns this aggregate function's simplification hook, if any.
    ///