Struct EventId 

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

A type-safe wrapper around a Felt that represents an event identifier.

Event IDs are used to identify events that can be emitted by the VM or handled by the host. This newtype provides type safety and ensures that event IDs are not accidentally confused with other Felt values.

While not enforced by this type, the values 0..256 are reserved for SystemEvents.

Implementations

impl EventId

pub fn from_name(name: impl AsRef<str>) -> Self

Computes the canonical event identifier for the given name.

This function provides a stable, deterministic mapping from human-readable event names to field elements that can be used as event identifiers in the VM. The mapping works by:

1. Computing the BLAKE3 hash of the event name (produces 32 bytes)
2. Taking the first 8 bytes of the hash
3. Interpreting these bytes as a little-endian u64
4. Reducing modulo the field prime to create a valid Felt

Note that this is the same procedure performed by hash_string_to_word, where we take the first element of the resulting Word.

This ensures that identical event names always produce the same event ID, while providing good distribution properties to minimize collisions between different names.

pub const fn from_felt(value: Felt) -> Self

Creates a new event ID from a Felt.

pub const fn from_u64(value: u64) -> Self

Creates a new event ID from a u64, converting it to a Felt.

pub const fn as_felt(&self) -> Felt

Returns the underlying Felt value.

pub const fn is_reserved(&self) -> bool

Returns true if this event ID is reserved for a SystemEvent.

Trait Implementations

impl Clone for EventId

fn clone(&self) -> EventId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EventId

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

Formats the value using the given formatter.

impl Display for EventId

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

Formats the value using the given formatter.

impl From<SystemEvent> for EventId

fn from(system_event: SystemEvent) -> Self

Converts to this type from the input type.

impl Ord for EventId

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 EventId

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

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 TryFrom<EventId> for SystemEvent

type Error = EventId

The type returned in the event of a conversion error.

fn try_from(event_id: EventId) -> Result<Self, Self::Error>

Performs the conversion.

impl Copy for EventId

impl Eq for EventId

impl StructuralPartialEq for EventId