Struct datafusion::common::tree_node::Transformed

pub struct Transformed<T> {
    pub data: T,
    pub transformed: bool,
    pub tnr: TreeNodeRecursion,
}

Result of tree walk / transformation APIs

API users control the transformation by returning:

• The resulting (possibly transformed) node,
• transformed: flag indicating whether any change was made to the node
• tnr: TreeNodeRecursion specifying how to proceed with the recursion.

At the end of the transformation, the return value will contain:

• The final (possibly transformed) tree,
• transformed: flag indicating whether any change was made to the node
• tnr: TreeNodeRecursion specifying how the recursion ended.

Example APIs:

• TreeNode,
• TreeNode::rewrite,
• TreeNode::transform_down,
• TreeNode::transform_up,
• TreeNode::transform_down_up

Fields

data: T

transformed: bool

tnr: TreeNodeRecursion

Implementations

impl<T> Transformed<T>

pub fn new(data: T, transformed: bool, tnr: TreeNodeRecursion) -> Transformed<T>

Create a new Transformed object with the given information.

pub fn yes(data: T) -> Transformed<T>

Wrapper for transformed data with TreeNodeRecursion::Continue statement.

pub fn no(data: T) -> Transformed<T>

Wrapper for unchanged data with TreeNodeRecursion::Continue statement.

pub fn update_data<U, F>(self, f: F) -> Transformed<U>

where F: FnOnce(T) -> U,

Applies an infallible f to the data of this Transformed object, without modifying the transformed flag.

pub fn map_data<U, F>(self, f: F) -> Result<Transformed<U>, DataFusionError>

where F: FnOnce(T) -> Result<U, DataFusionError>,

Applies a fallible f (returns Result) to the data of this Transformed object, without modifying the transformed flag.

pub fn transform_data<U, F>( self, f: F, ) -> Result<Transformed<U>, DataFusionError>

where F: FnOnce(T) -> Result<Transformed<U>, DataFusionError>,

Applies a fallible transforming f to the data of this Transformed object.

The returned Transformed object has the transformed flag set if either self or the return value of f have the transformed flag set.

pub fn transform_children<F>( self, f: F, ) -> Result<Transformed<T>, DataFusionError>

where F: FnOnce(T) -> Result<Transformed<T>, DataFusionError>,

Maps the Transformed object to the result of the given f depending on the current TreeNodeRecursion value and the fact that f is changing the current node’s children.

pub fn transform_sibling<F>( self, f: F, ) -> Result<Transformed<T>, DataFusionError>

where F: FnOnce(T) -> Result<Transformed<T>, DataFusionError>,

Maps the Transformed object to the result of the given f depending on the current TreeNodeRecursion value and the fact that f is changing the current node’s sibling.

pub fn transform_parent<F>( self, f: F, ) -> Result<Transformed<T>, DataFusionError>

where F: FnOnce(T) -> Result<Transformed<T>, DataFusionError>,

Maps the Transformed object to the result of the given f depending on the current TreeNodeRecursion value and the fact that f is changing the current node’s parent.

Trait Implementations

impl<T> Debug for Transformed<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T> PartialEq for Transformed<T>

where T: PartialEq,

fn eq(&self, other: &Transformed<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> StructuralPartialEq for Transformed<T>