Struct canrun::core::LVar

pub struct LVar<T> { /* private fields */ }

A logical variable that represents a potential value of type T.

LVars are are passed into goals to relate values and other variables to each other. They can also be used to query for values.

The main reason to deal with an LVar directly as opposed to just Value::Var is that LVar implements Copy, which makes it more convenient when the same var is shared between various goals, closures and other places.

The identity of each LVar is tracked using an internal id. While this id is visible through the Debug implementation, it should only be used for debugging purposes as no guarantees are made about the type or generation of the id value. Also, these ids are only valid within the context of a single execution. They cannot be safely persisted or shared between processes.

Implementations

impl<T: Unify> LVar<T>

pub fn new() -> Self

Create a new logical var.

Example:

use canrun::LVar;
let x: LVar<isize> = LVar::new();

Trait Implementations

impl<T> Clone for LVar<T>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for LVar<T>

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

Formats the value using the given formatter.

impl<T: Unify> Default for LVar<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Unify> From<&LVar<T>> for Value<T>

fn from(var: &LVar<T>) -> Self

Converts to this type from the input type.

impl<T: Unify> From<LVar<T>> for Value<T>

fn from(var: LVar<T>) -> Self

Converts to this type from the input type.

impl<T> Hash for LVar<T>

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<T> PartialEq<LVar<T>> for LVar<T>

fn eq(&self, other: &LVar<T>) -> bool

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Unify + Reify> Reify for LVar<T>

type Reified = <T as Reify>::Reified

The “concrete” type that Self reifies to.

fn reify_in(&self, state: &State) -> Option<Self::Reified>

Extract a reified Self from a compatible State. This trait is usually used indirectly through the Query trait.

impl<T: Copy> Copy for LVar<T>

impl<T: Eq> Eq for LVar<T>

impl<T> StructuralEq for LVar<T>