Enum Index 

pub enum Index {
    Unique,
    Grouped {
        by: Core,
        param: VarId,
        answers: Answers,
    },
}

The index a lookup is answered from — the one difference between the two shapes recognised.

Variants

Unique

map_get(m, k(x)): the collection is a Map whose own key is the join key, so the index is the crate::plan::Op::MapValues arrangement that already exists and hash-consing shares it with every other reader of the same collection. At most one row answers.

Grouped

filter_list(xs, lambda y: by(y) == k(x)): nothing keys xs by by, so the index is an crate::plan::Op::ArrangeBy built for the purpose. Several rows share a key and the group answers — either its rows or a question about them.

Fields

by: Core

What the collection is arranged by, as a function of one of its own elements.

param: VarId

The parameter by is written over — the filtered element, not the loop’s.

answers: Answers

What the body asked the group for.

Trait Implementations

impl Clone for Index

fn clone(&self) -> Index

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Index

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

Formats the value using the given formatter.