Enum ViewNode 

pub enum ViewNode {
    Scan {
        df: Rc<DataFrame>,
    },
    Filter {
        input: Box<ViewNode>,
        predicate: DExpr,
    },
    Select {
        input: Box<ViewNode>,
        columns: Vec<String>,
    },
    Mutate {
        input: Box<ViewNode>,
        assignments: Vec<(String, DExpr)>,
    },
    Arrange {
        input: Box<ViewNode>,
        keys: Vec<ArrangeKey>,
    },
    GroupSummarise {
        input: Box<ViewNode>,
        group_keys: Vec<String>,
        aggregations: Vec<(String, TidyAgg)>,
    },
    StreamingGroupSummarise {
        input: Box<ViewNode>,
        group_keys: Vec<String>,
        aggregations: Vec<(String, StreamingAgg)>,
    },
    Distinct {
        input: Box<ViewNode>,
        columns: Vec<String>,
    },
    Join {
        left: Box<ViewNode>,
        right: Box<ViewNode>,
        on: Vec<(String, String)>,
        kind: JoinType,
    },
}

A node in the lazy evaluation tree.

Variants

Scan

Leaf: scan a base DataFrame.

Fields

df: Rc<DataFrame>

Filter

Filter rows by predicate.

Fields

input: Box<ViewNode>

predicate: DExpr

Select

Project to subset of columns.

Fields

input: Box<ViewNode>

columns: Vec<String>

Mutate

Add/replace columns via expressions.

Fields

input: Box<ViewNode>

assignments: Vec<(String, DExpr)>

Arrange

Sort by keys.

Fields

input: Box<ViewNode>

keys: Vec<ArrangeKey>

GroupSummarise

Group + summarise (pipeline breaker).

Fields

input: Box<ViewNode>

group_keys: Vec<String>

aggregations: Vec<(String, TidyAgg)>

StreamingGroupSummarise

v3 Phase 6: streaming-friendly group + summarise. Produced by the lazy optimizer (annotate_streamable_summarise) when every aggregation is one of {Count, Sum, Mean, Min, Max, Var, Sd}. At execution this dispatches to TidyView::summarise_streaming, avoiding the per-group Vec<usize> materialisation.

Fields

input: Box<ViewNode>

group_keys: Vec<String>

aggregations: Vec<(String, StreamingAgg)>

Distinct

Distinct on columns.

Fields

input: Box<ViewNode>

columns: Vec<String>

Join

Join two inputs.

Fields

left: Box<ViewNode>

right: Box<ViewNode>

on: Vec<(String, String)>

kind: JoinType

Implementations

impl ViewNode

pub fn count_filters(&self) -> usize

Count the number of Filter nodes in the tree.

pub fn is_filter_on_scan(&self) -> bool

Check if the immediate child (input) of the outermost node is a Scan. Useful for verifying predicate pushdown moved a filter near the scan.

pub fn innermost(&self) -> &ViewNode

Return the innermost node (the leaf Scan) by walking input chains.

pub fn kind(&self) -> &'static str

Return the node kind name (for test assertions).

pub fn node_kinds(&self) -> Vec<&'static str>

Walk the plan tree depth-first and collect node kinds top-down.

Trait Implementations

impl Clone for ViewNode

fn clone(&self) -> ViewNode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ViewNode

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

Formats the value using the given formatter.