Struct chalk_engine::ExClause

pub struct ExClause<I: Interner> {
    pub subst: Substitution<I>,
    pub ambiguous: bool,
    pub constraints: Vec<InEnvironment<Constraint<I>>>,
    pub subgoals: Vec<Literal<I>>,
    pub delayed_subgoals: Vec<InEnvironment<Goal<I>>>,
    pub answer_time: TimeStamp,
    pub floundered_subgoals: Vec<FlounderedSubgoal<I>>,
}

The paper describes these as A :- D | G.

Fields

subst: Substitution<I>

The substitution which, applied to the goal of our table, would yield A.

ambiguous: bool

True if any subgoals were depended upon negatively and were not fully evaluated, or if we encountered a CannotProve goal. (In the full SLG algorithm, we would use delayed literals here, but we don’t bother, as we don’t need that support.)

constraints: Vec<InEnvironment<Constraint<I>>>

Region constraints we have accumulated.

subgoals: Vec<Literal<I>>

Subgoals: literals that must be proven

delayed_subgoals: Vec<InEnvironment<Goal<I>>>

We assume that negative literals cannot have coinductive cycles.

answer_time: TimeStamp

Time stamp that is incremented each time we find an answer to some subgoal. This is used to figure out whether any of the floundered subgoals may no longer be floundered: we record the current time when we add something to the list of floundered subgoals, and then we can compare whether its value has changed since then. This is not the same TimeStamp of Forest’s clock.

floundered_subgoals: Vec<FlounderedSubgoal<I>>

List of subgoals that have floundered. See FlounderedSubgoal for more information.

Trait Implementations

impl<I: Clone + Interner> Clone for ExClause<I>

fn clone(&self) -> ExClause<I>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<I: Debug + Interner> Debug for ExClause<I>

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

Formats the value using the given formatter.

impl<I: Interner> Fold<I> for ExClause<I>

type Result = ExClause<I>

The type of value that will be produced once folding is done. Typically this is Self, unless Self contains borrowed values, in which case owned values are produced (for example, one can fold over a &T value where T: Fold, in which case you get back a T, not a &T).

fn fold_with<'i>(
    self,
    folder: &mut dyn Folder<'i, I>,
    outer_binder: DebruijnIndex
) -> Fallible<Self::Result> where
    I: 'i, 

Apply the given folder folder to self; binders is the number of binders that are in scope when beginning the folder. Typically binders starts as 0, but is adjusted when we encounter Binders<T> in the IR or other similar constructs.

impl<I: Interner> HasInterner for ExClause<I>

type Interner = I

The interner associated with the type.

impl<I: Hash + Interner> Hash for ExClause<I>

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<I: PartialEq + Interner> PartialEq<ExClause<I>> for ExClause<I>

fn eq(&self, other: &ExClause<I>) -> bool

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

fn ne(&self, other: &ExClause<I>) -> bool

This method tests for !=.

impl<I: Interner> Visit<I> for ExClause<I>

fn visit_with<'i, B>(
    &self,
    visitor: &mut dyn Visitor<'i, I, BreakTy = B>,
    outer_binder: DebruijnIndex
) -> ControlFlow<B> where
    I: 'i, 

Apply the given visitor visitor to self; binders is the number of binders that are in scope when beginning the visitor. Typically binders starts as 0, but is adjusted when we encounter Binders<T> in the IR or other similar constructs.

impl<I: Eq + Interner> Eq for ExClause<I>

impl<I: Interner> StructuralEq for ExClause<I>

impl<I: Interner> StructuralPartialEq for ExClause<I>