Struct TyVar 

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

An inference variable — a placeholder for a type not yet known.

A TyVar is a 32-bit handle minted by Unifier::fresh and stable for the life of that unifier. It is deliberately opaque: there is no public constructor, so a variable can only be obtained from a unifier. Mint and use variables in the same unifier — a handle is an index into that unifier’s id space, and a unifier treats an id it has not minted as an unbound variable, so a handle is only meaningful against the unifier that produced it.

A variable starts life unbound — it stands for “some type” — and unification may bind it to a concrete type or to another variable. Use Unifier::resolve to read back what a variable has become; a variable that is still unbound resolves to itself.

Examples

use type_lang::Unifier;

let mut unifier = Unifier::new();
let a = unifier.fresh();
let b = unifier.fresh();

// Variables are minted in order and stay distinct.
assert_eq!(a.to_u32(), 0);
assert_eq!(b.to_u32(), 1);
assert_ne!(a, b);

Implementations

impl TyVar

pub const fn to_u32(self) -> u32

Returns the raw index this variable wraps.

The value is the variable’s creation order, starting at 0. It is useful as a dense key into a side table of per-variable data; prefer passing the opaque TyVar itself wherever a handle will do.

Examples

use type_lang::Unifier;

let mut unifier = Unifier::new();
let v = unifier.fresh();
assert_eq!(v.to_u32(), 0);

Trait Implementations

impl Clone for TyVar

fn clone(&self) -> TyVar

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TyVar

impl Debug for TyVar

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TyVar

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for TyVar

impl Hash for TyVar

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 TyVar

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

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

fn partial_cmp(&self, other: &TyVar) -> 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 TyVar

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for TyVar