Method transform_down_up

datafusion/common/src/tree_node.rs:366–392

Transforms the node using `f_down` while traversing the tree top-down (pre-order), and using `f_up` while traversing the tree bottom-up (post-order). The method behaves the same as calling [`Self::transform_down`] followed by [`Self::transform_up`] on the same node. Use this method if you want to start the `f_up` process right where `f_down` jumps. This can make the whole process faster by reduci

(
        self,
        mut f_down: FD,
        mut f_up: FU,
    )

    ///                                                  +---+
    /// ```
    fn transform_down_up<
        FD: FnMut(Self) -> Result<Transformed<Self>>,
        FU: FnMut(Self) -> Result<Transformed<Self>>,
    >(
        self,
        mut f_down: FD,
        mut f_up: FU,
    ) -> Result<Transformed<Self>> {
        #[cfg_attr(feature = "recursive_protection", recursive::recursive)]
        fn transform_down_up_impl<
            N: TreeNode,
            FD: FnMut(N) -> Result<Transformed<N>>,
            FU: FnMut(N) -> Result<Transformed<N>>,
        >(
            node: N,
            f_down: &mut FD,
            f_up: &mut FU,
        ) -> Result<Transformed<N>> {
            handle_transform_recursion!(
                f_down(node),
                |c| transform_down_up_impl(c, f_down, f_up),
                f_up
            )
        }

        transform_down_up_impl(self, &mut f_down, &mut f_up)
    }

    /// Returns true if `f` returns true for any node in the tree.
    ///