Struct ConstantSymbol 

pub struct ConstantSymbol { /* private fields */ }

Constant symbol used in Datalog terms.

Like VariableSymbol, carries a precomputed FxHash of its value alongside the Arc<str>. Constants often dominate evaluator hot paths — a hash-join frontier index (FxHashMap<GroundTerm, _>) hashes a constant on every probe, and unify_one compares constants on every fact cell — so a cached hash (fed as a single u64) plus a hash-prefiltered equality cut the per-fact term cost. Profile justification: profiling of a bulk rule-materialization benchmark showed GroundTerm PartialEq plus hash-join index’s GroundTerm hashing at ~20 % of total samples, all content-based on the constant Arc<str>.

Ordering stays content-based so BTreeSet / BTreeMap order (a relation prefix index may rely on it for range queries) is independent of the hasher seed — the same split VariableSymbol makes.

Implementations

impl ConstantSymbol

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

Construct a constant symbol. Computes the cached hash of value once; subsequent Hash calls feed that u64 to whatever hasher the map uses.

pub fn as_str(&self) -> &str

Access the raw constant identifier.

Trait Implementations

impl Clone for ConstantSymbol

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConstantSymbol

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

Formats the value using the given formatter.

impl Eq for ConstantSymbol

impl From<ConstantSymbol> for GroundTerm

fn from(c: ConstantSymbol) -> Self

Converts to this type from the input type.

impl Hash for ConstantSymbol

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 ConstantSymbol

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.

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 ConstantSymbol

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for ConstantSymbol

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.