pub struct BoundVar {
pub debruijn: DebruijnIndex,
pub index: usize,
}
Expand description
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§
source§impl BoundVar
impl BoundVar
sourcepub fn new(debruijn: DebruijnIndex, index: usize) -> Self
pub fn new(debruijn: DebruijnIndex, index: usize) -> Self
Creates a new bound variable.
sourcepub fn to_lifetime<I: Interner>(self, interner: I) -> Lifetime<I>
pub fn to_lifetime<I: Interner>(self, interner: I) -> Lifetime<I>
Wrap the bound variable in a lifetime.
sourcepub fn to_const<I: Interner>(self, interner: I, ty: Ty<I>) -> Const<I>
pub fn to_const<I: Interner>(self, interner: I, ty: Ty<I>) -> Const<I>
Wraps the bound variable in a constant.
sourcepub fn bound_within(self, outer_binder: DebruijnIndex) -> bool
pub fn bound_within(self, outer_binder: DebruijnIndex) -> bool
True if this variable is bound within the amount
innermost binders.
sourcepub fn shifted_in(self) -> Self
pub fn shifted_in(self) -> Self
Adjusts the debruijn index (see DebruijnIndex::shifted_in
).
sourcepub fn shifted_in_from(self, outer_binder: DebruijnIndex) -> Self
pub fn shifted_in_from(self, outer_binder: DebruijnIndex) -> Self
Adjusts the debruijn index (see DebruijnIndex::shifted_in
).
sourcepub fn shifted_out(self) -> Option<Self>
pub fn shifted_out(self) -> Option<Self>
Adjusts the debruijn index (see DebruijnIndex::shifted_in
).
sourcepub fn shifted_out_to(self, outer_binder: DebruijnIndex) -> Option<Self>
pub fn shifted_out_to(self, outer_binder: DebruijnIndex) -> Option<Self>
Adjusts the debruijn index (see DebruijnIndex::shifted_in
).
sourcepub fn index_if_innermost(self) -> Option<usize>
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
.
sourcepub fn index_if_bound_at(self, debruijn: DebruijnIndex) -> Option<usize>
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§
source§impl Ord for BoundVar
impl Ord for BoundVar
source§impl PartialEq<BoundVar> for BoundVar
impl PartialEq<BoundVar> for BoundVar
source§impl PartialOrd<BoundVar> for BoundVar
impl PartialOrd<BoundVar> for BoundVar
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read more