Struct Sequence 

pub struct Sequence(/* private fields */);

Monotonic event sequence number for event ordering.

Each event processed by a driver is assigned a unique sequence number via World::next_sequence. Handlers can read the current sequence via Seq or advance it via SeqMut.

Uses i64 for wire-format compatibility (FIX/SBE, Protobuf, Avro all have native signed 64-bit; unsigned is awkward or absent) and to support sentinel values (NULL, UNINITIALIZED) without Option overhead.

Wrapping is harmless — at one increment per event, the positive i64 space takes ~292 years at 1 GHz to exhaust.

Sentinels

Constant	Value	Meaning
NULL	i64::MIN	No sequence exists (SBE null convention)
UNINITIALIZED	-1	Not yet assigned
ZERO	0	Starting point before any events

Examples

use nexus_rt::Sequence;

let a = Sequence::ZERO;
let b = a.next();

assert!(b > a);
assert_eq!(b.as_i64(), 1);
assert_eq!(b.elapsed_since(a), 1);

assert!(Sequence::NULL.is_null());
assert!(!Sequence::ZERO.is_null());

Implementations

impl Sequence

pub const NULL: Self

SBE-compatible null — i64::MIN. Indicates no sequence exists.

Maps directly to the SBE int64 null sentinel on the wire.

pub const UNINITIALIZED: Self

Uninitialized sentinel — -1. Indicates a sequence has not yet been assigned.

pub const ZERO: Self

The zero sequence — the starting point before any events.

pub const fn new(value: i64) -> Self

Create a sequence from a raw i64 value.

Use for construction in tests, deserialization, or replay.

pub const fn from_i64(value: i64) -> Self

Create a sequence from a raw i64 value.

Symmetric with as_i64. Use for wire protocol deserialization.

pub const fn as_i64(self) -> i64

Returns the raw i64 value.

Use for logging, metrics, serialization, or passing to external systems.

pub const fn is_null(self) -> bool

Returns true if this is the NULL sentinel.

pub const fn is_uninitialized(self) -> bool

Returns true if this is the UNINITIALIZED sentinel.

pub const fn next(self) -> Self

Returns the next sequence number (wrapping).

This is a pure computation — it does not advance any world state. Use World::next_sequence to actually advance the world’s current sequence.

pub const fn elapsed_since(self, earlier: Self) -> i64

Returns the number of events between earlier and self.

Wrapping-aware: if self has wrapped past earlier, the result is the wrapping distance. Returns 0 if self == earlier.

Trait Implementations

impl Clone for Sequence

fn clone(&self) -> Sequence

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Sequence

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

Formats the value using the given formatter.

impl Default for Sequence

fn default() -> Sequence

Returns the “default value” for a type.

impl Display for Sequence

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

Formats the value using the given formatter.

impl Hash for Sequence

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 Sequence

fn cmp(&self, other: &Sequence) -> 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 Sequence

fn eq(&self, other: &Sequence) -> 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 Sequence

fn partial_cmp(&self, other: &Sequence) -> 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 Copy for Sequence

impl Eq for Sequence

impl StructuralPartialEq for Sequence