Struct Rga 

pub struct Rga<T: Clone + Ord> { /* private fields */ }

A Replicated Growable Array (RGA) — an ordered sequence CRDT.

RGA supports insert and delete at arbitrary positions while guaranteeing convergence across replicas. Each element is assigned a unique identifier (actor, counter) which determines causal ordering. When two replicas concurrently insert at the same position, the conflict is resolved deterministically by comparing the unique identifiers, ensuring all replicas converge to the same sequence after merging.

Example

use crdt_kit::prelude::*;

let mut list1 = Rga::new("node-1");
list1.insert_at(0, 'H');
list1.insert_at(1, 'i');

let mut list2 = Rga::new("node-2");
list2.insert_at(0, '!');

list1.merge(&list2);
list2.merge(&list1);

// Both replicas converge to the same sequence
let v1: Vec<&char> = list1.iter().collect();
let v2: Vec<&char> = list2.iter().collect();
assert_eq!(v1, v2);
assert_eq!(list1.len(), 3);

Implementations

impl<T: Clone + Ord> Rga<T>

pub fn new(actor: impl Into<String>) -> Self

Create a new empty RGA for the given actor.

pub fn insert_at(&mut self, index: usize, value: T)

Insert a value at the given index in the visible sequence.

Panics

Panics if index > self.len().

pub fn remove(&mut self, index: usize) -> Option<T>

Remove the element at the given index from the visible sequence.

Returns the removed value, or None if the index is out of bounds.

pub fn get(&self, index: usize) -> Option<&T>

Get a reference to the element at the given index in the visible sequence.

pub fn len(&self) -> usize

Get the number of visible (non-tombstoned) elements.

pub fn is_empty(&self) -> bool

Check if the visible sequence is empty.

pub fn iter(&self) -> impl Iterator<Item = &T>

Iterate over the visible elements in order.

pub fn actor(&self) -> &str

Get this replica’s actor ID.

pub fn to_vec(&self) -> Vec<T>

Collect visible elements into a Vec.

Trait Implementations

impl<T: Clone + Clone + Ord> Clone for Rga<T>

fn clone(&self) -> Rga<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Clone + Ord> Crdt for Rga<T>

fn merge(&mut self, other: &Self)

Merge another replica’s state into this one.

impl<T: Debug + Clone + Ord> Debug for Rga<T>

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

Formats the value using the given formatter.

impl<T: PartialEq + Clone + Ord> PartialEq for Rga<T>

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl<T: Eq + Clone + Ord> Eq for Rga<T>

impl<T: Clone + Ord> StructuralPartialEq for Rga<T>