Struct chalk_ir::BoundVar

pub struct BoundVar {
    pub debruijn: DebruijnIndex,
    pub index: usize,
}

Identifies a particular bound variable within a binder. Variables are identified by the combination of a DebruijnIndex, which identifies the binder, and an index within that binder.

Consider this case:

forall<'a, 'b> { forall<'c, 'd> { ... } }

Within the ... term:

• the variable 'a have a debruijn index of 1 and index 0
• the variable 'b have a debruijn index of 1 and index 1
• the variable 'c have a debruijn index of 0 and index 0
• the variable 'd have a debruijn index of 0 and index 1

The variables 'a and 'b both have debruijn index of 1 because, counting out, they are the 2nd binder enclosing .... The indices identify the location within that binder.

The variables 'c and 'd both have debruijn index of 0 because they appear in the innermost binder enclosing the .... The indices identify the location within that binder.

Fields

debruijn: DebruijnIndex

Debruijn index, which identifies the binder.

index: usize

Index within the binder.

Implementations

impl BoundVar

pub fn new(debruijn: DebruijnIndex, index: usize) -> Self

Creates a new bound variable.

pub fn to_ty<I: Interner>(self, interner: &I) -> Ty<I>

Casts the bound variable to a type.

pub fn to_lifetime<I: Interner>(self, interner: &I) -> Lifetime<I>

Wrap the bound variable in a lifetime.

pub fn to_const<I: Interner>(self, interner: &I, ty: Ty<I>) -> Const<I>

Wraps the bound variable in a constant.

pub fn bound_within(self, outer_binder: DebruijnIndex) -> bool

True if this variable is bound within the amount innermost binders.

#[must_use]

pub fn shifted_in(self) -> Self

Adjusts the debruijn index (see DebruijnIndex::shifted_in).

#[must_use]

pub fn shifted_in_from(self, outer_binder: DebruijnIndex) -> Self

Adjusts the debruijn index (see DebruijnIndex::shifted_in).

#[must_use]

pub fn shifted_out(self) -> Option<Self>

Adjusts the debruijn index (see DebruijnIndex::shifted_in).

#[must_use]

pub fn shifted_out_to(self, outer_binder: DebruijnIndex) -> Option<Self>

Adjusts the debruijn index (see DebruijnIndex::shifted_in).

pub fn index_if_innermost(self) -> Option<usize>

Return the index of the bound variable, but only if it is bound at the innermost binder. Otherwise, returns None.

pub fn index_if_bound_at(self, debruijn: DebruijnIndex) -> Option<usize>

Return the index of the bound variable, but only if it is bound at the innermost binder. Otherwise, returns None.

Trait Implementations

impl Clone for BoundVar

fn clone(&self) -> BoundVar

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for BoundVar

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

Formats the value using the given formatter.

impl Hash for BoundVar

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, 

Feeds a slice of this type into the given Hasher.

impl Ord for BoundVar

fn cmp(&self, other: &BoundVar) -> Ordering

This method returns an Ordering between self and other.

#[must_use]

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<BoundVar> for BoundVar

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialOrd<BoundVar> for BoundVar

fn partial_cmp(&self, other: &BoundVar) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

#[must_use]

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

This method tests less than (for self and other) and is used by the < operator.

#[must_use]

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

#[must_use]

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

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for BoundVar

impl Eq for BoundVar

impl StructuralEq for BoundVar

impl StructuralPartialEq for BoundVar