Trait differential_dataflow::trace::layers::Trie

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pub trait Trie: Sized {
    type Item;
    type Cursor: Cursor<Self>;
    type MergeBuilder: MergeBuilder<Trie = Self>;
    type TupleBuilder: TupleBuilder<Trie = Self, Item = Self::Item>;

    // Required methods
    fn keys(&self) -> usize;
    fn tuples(&self) -> usize;
    fn cursor_from(&self, lower: usize, upper: usize) -> Self::Cursor;

    // Provided methods
    fn cursor(&self) -> Self::Cursor { ... }
    fn merge(&self, other: &Self) -> Self { ... }
}

Expand description

A collection of tuples, and types for building and enumerating them.

There are some implicit assumptions about the elements in trie-structured data, mostly that the items have some (key, val) structure. Perhaps we will nail these down better in the future and get a better name for the trait.

Required Associated Types§

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type Item

The type of item from which the type is constructed.

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type Cursor: Cursor<Self>

The type of cursor used to navigate the type.

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type MergeBuilder: MergeBuilder<Trie = Self>

The type used to merge instances of the type together.

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type TupleBuilder: TupleBuilder<Trie = Self, Item = Self::Item>

The type used to assemble instances of the type from its Items.

Required Methods§

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fn keys(&self) -> usize

The number of distinct keys, as distinct from the total number of tuples.

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fn tuples(&self) -> usize

The total number of tuples in the collection.

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fn cursor_from(&self, lower: usize, upper: usize) -> Self::Cursor

Returns a cursor over a range of data, commonly used by others to restrict navigation to sub-collections.

Provided Methods§

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fn cursor(&self) -> Self::Cursor

Returns a cursor capable of navigating the collection.

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fn merge(&self, other: &Self) -> Self

Merges two collections into a third.

Collections are allowed their own semantics for merging. For example, unordered collections simply collect values, whereas weighted collections accumulate weights and discard elements whose weights are zero.