Struct EventId 

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

A type-safe event identifier that semantically represents a Felt value.

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 field element values.

Internally stored as u64 rather than Felt to enable const construction.

EventId contains only the identifier. For events with human-readable names, use EventName instead.

Event IDs are derived from event names using blake3 hashing.

Implementations

impl EventId

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

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 produce a valid field element

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 fn from_felt(event_id: Felt) -> EventId

Creates an EventId from a Felt value (e.g., from the stack).

pub const fn from_u64(event_id: u64) -> EventId

Creates an EventId from a u64 value, reducing modulo the field prime.

pub const fn as_felt(&self) -> Felt

Converts this event ID to a Felt.

pub const fn as_u64(&self) -> u64

Returns the inner u64 representation.

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 Copy for EventId

impl Debug for EventId

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

Formats the value using the given formatter.

impl Deserializable for EventId

fn read_from<R>(source: &mut R) -> Result<EventId, DeserializationError>

where R: ByteReader,

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn min_serialized_size() -> usize

Returns the minimum serialized size for one instance of this type.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

fn read_from_bytes_with_budget( bytes: &[u8], budget: usize, ) -> Result<Self, DeserializationError>

Deserializes Self from bytes with a byte budget limit.

impl<'de> Deserialize<'de> for EventId

fn deserialize<__D>( __deserializer: __D, ) -> Result<EventId, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for EventId

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

Formats the value using the given formatter.

impl Eq for EventId

impl From<Event> for EventId

fn from(event: Event) -> EventId

Converts to this type from the input type.

impl Hash for EventId

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

where __H: Hasher,

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 EventId

fn cmp(&self, other: &EventId) -> 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.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for EventId

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for EventId

fn partial_cmp(&self, other: &EventId) -> 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 Serializable for EventId

fn write_into<W>(&self, target: &mut W)

where W: ByteWriter,

Serializes self into bytes and writes these bytes into the target.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

impl Serialize for EventId

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for EventId