Struct Position 

pub struct Position {
    pub numerator: i64,
    pub denominator: u64,
    pub unique_id: Uuid,
}

Represents a position in a CRDT list using rational numbers.

This type provides a stable ordering mechanism for list elements that allows insertion between any two existing elements without requiring renumbering. Each position consists of:

• A rational number (numerator/denominator) for ordering
• A unique UUID for deterministic tie-breaking

Examples

use eidetica::crdt::doc::list::Position;

let pos1 = Position::new(10, 1);
let pos2 = Position::new(20, 1);
let between = Position::between(&pos1, &pos2);

assert!(pos1 < between);
assert!(between < pos2);

Fields

numerator: i64

Numerator of the rational number

denominator: u64

Denominator of the rational number (always positive)

unique_id: Uuid

Unique identifier for deterministic ordering

Implementations

impl Position

pub fn new(numerator: i64, denominator: u64) -> Self

Creates a new position with the specified rational number.

Arguments

• numerator - The numerator of the rational number
• denominator - The denominator of the rational number (must be > 0)

Examples

use eidetica::crdt::doc::list::Position;

let pos = Position::new(3, 2); // Represents 3/2 = 1.5

pub fn beginning() -> Self

Creates a position at the beginning of the sequence.

Examples

use eidetica::crdt::doc::list::Position;

let beginning = Position::beginning();
let after = Position::new(1, 1);
assert!(beginning < after);

pub fn end() -> Self

Creates a position at the end of the sequence.

Examples

use eidetica::crdt::doc::list::Position;

let end = Position::end();
let before = Position::new(1000, 1);
assert!(before < end);

pub fn between(left: &Position, right: &Position) -> Self

Creates a position between two existing positions.

This method finds the rational number that falls between the two given positions and creates a new position with that value.

Arguments

• left - The left (smaller) position
• right - The right (larger) position

Examples

use eidetica::crdt::doc::list::Position;

let pos1 = Position::new(1, 1);
let pos2 = Position::new(3, 1);
let between = Position::between(&pos1, &pos2);

assert!(pos1 < between);
assert!(between < pos2);

pub fn as_f64(&self) -> f64

Returns the rational value as a floating point number.

Note: This is primarily for debugging and should not be used for ordering.

Trait Implementations

impl Clone for Position

fn clone(&self) -> Position

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Position

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Position

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for Position

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Position

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Position

fn eq(&self, other: &Position) -> 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 PartialOrd for Position

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Position

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for Position

impl StructuralPartialEq for Position