Struct StarImportPlaceholderPredicate 

pub struct StarImportPlaceholderPredicate<'db>(/* private fields */);

A “placeholder predicate” that is used to model the fact that the boundness of a (possible) definition or declaration caused by a * import cannot be fully determined until type- inference time. This is essentially the same as a standard reachability constraint, so we reuse the Predicate infrastructure to model it.

To illustrate, say we have a module exporter.py like so:

if <condition>:
    class A: ...

and we have a module importer.py like so:

A = 1

from exporter import *

Since we cannot know whether or not is true at semantic-index time, we record a definition for A in importer.py as a result of the from exporter import * statement, but place a predicate on it to record the fact that we don’t yet know whether this definition will be visible from all control-flow paths or not. Essentially, we model importer.py as something similar to this:

A = 1

if <star_import_placeholder_predicate>:
    from a import A

At type-check time, the placeholder predicate for the A definition is evaluated by attempting to resolve the A symbol in exporter.py’s global namespace:

• If it resolves to a definitely bound symbol, then the predicate resolves to [Truthiness::AlwaysTrue]
• If it resolves to an unbound symbol, then the predicate resolves to [Truthiness::AlwaysFalse]
• If it resolves to a possibly bound symbol, then the predicate resolves to [Truthiness::Ambiguous]

Implementations

impl StarImportPlaceholderPredicate<'static>

pub fn ingredient(db: &dyn Database) -> &IngredientImpl<Self>

impl<'db> StarImportPlaceholderPredicate<'db>

pub fn new<Db_>( db: &'db Db_, importing_file: ProgramFile<'db>, symbol_id: ScopedSymbolId, referenced_file: ProgramFile<'db>, ) -> Self

where Db_: ?Sized + Database,

pub fn importing_file<Db_>(self, db: &'db Db_) -> ProgramFile<'db>

where Db_: ?Sized + Database,

pub fn symbol_id<Db_>(self, db: &'db Db_) -> ScopedSymbolId

where Db_: ?Sized + Database,

Each symbol imported by a * import has a separate predicate associated with it: this field identifies which symbol that is.

Note that a [ScopedPlaceId] is only meaningful if you also know the scope it is relative to. For this specific struct, however, there’s no need to store a separate field to hold the ID of the scope. StarImportPredicates are only created for valid *-import definitions, and valid *-import definitions can only ever exist in the global scope; thus, we know that the symbol_id here will be relative to the global scope of the importing file.

pub fn referenced_file<Db_>(self, db: &'db Db_) -> ProgramFile<'db>

where Db_: ?Sized + Database,

impl<'_db> StarImportPlaceholderPredicate<'_db>

pub fn default_debug_fmt(this: Self, f: &mut Formatter<'_>) -> Result

where for<'db, 'db> ProgramFile<'db>: Debug, for<'db> ScopedSymbolId: Debug,

Default debug formatting for this struct (may be useful if you define your own Debug impl)

impl<'db> StarImportPlaceholderPredicate<'db>

pub fn scope(self, db: &'db dyn Db) -> ScopeId<'db>

Trait Implementations

impl AsId for StarImportPlaceholderPredicate<'_>

fn as_id(&self) -> Id

impl<'db> Clone for StarImportPlaceholderPredicate<'db>

fn clone(&self) -> StarImportPlaceholderPredicate<'db>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Configuration for StarImportPlaceholderPredicate<'static>

const LOCATION: Location

const DEBUG_NAME: &'static str = "StarImportPlaceholderPredicate"

The debug name of the tracked struct.

const TRACKED_FIELD_NAMES: &'static [&'static str]

The debug names of any tracked fields.

const TRACKED_FIELD_INDICES: &'static [usize]

The relative indices of any tracked fields.

const PERSIST: bool = false

Whether this struct should be persisted with the database.

type Fields<'db> = (ProgramFile<'db>, ScopedSymbolId, ProgramFile<'db>)

A (possibly empty) tuple of the fields for this struct.

type Revisions = [AtomicRevision; 0]

type Struct<'db> = StarImportPlaceholderPredicate<'db>

fn untracked_fields(fields: &Self::Fields<'_>) -> impl Hash

fn new_revisions(current_revision: Revision_) -> Self::Revisions

Create a new value revision array where each element is set to current_revision.

fn update_fields<'db>( current_revision: Revision_, revisions: &Self::Revisions, old_fields: &mut Self::Fields<'db>, new_fields: Self::Fields<'db>, ) -> bool

Update the field data and, if the value has changed, the appropriate entry in the revisions array (tracked fields only).

fn heap_size(value: &Self::Fields<'_>) -> Option<usize>

Returns the size of any heap allocations in the output value, in bytes.

fn serialize<S: Serializer>( fields: &Self::Fields<'_>, serializer: S, ) -> Result<S::Ok, S::Error>

Serialize the fields using serde.

fn deserialize<'de, D: Deserializer<'de>>( deserializer: D, ) -> Result<Self::Fields<'static>, D::Error>

Deserialize the fields using serde.

impl<'db> Copy for StarImportPlaceholderPredicate<'db>

impl Debug for StarImportPlaceholderPredicate<'_>

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

Formats the value using the given formatter.

impl<'db> Eq for StarImportPlaceholderPredicate<'db>

impl<'db> FromId for StarImportPlaceholderPredicate<'db>

fn from_id(id: Id) -> Self

impl GetSize for StarImportPlaceholderPredicate<'_>

fn get_stack_size() -> usize

Determines how may bytes this object occupies inside the stack.

fn get_heap_size(&self) -> usize

Determines how many bytes this object occupies inside the heap.

fn get_heap_size_with_tracker<T>(&self, tracker: T) -> (usize, T)

where T: GetSizeTracker,

Determines how many bytes this object occupies inside the heap while using a tracker.

fn get_size(&self) -> usize

Determines the total size of the object.

fn get_size_with_tracker<T>(&self, tracker: T) -> (usize, T)

where T: GetSizeTracker,

Determines the total size of the object while using a tracker.

impl<'db> HasJar for StarImportPlaceholderPredicate<'db>

const KIND: JarKind = zalsa_::JarKind::Struct

The [JarKind] for Self::Jar.

type Jar = JarImpl<StarImportPlaceholderPredicate<'static>>

The [Jar] associated with this ingredient.

impl<'db> Hash for StarImportPlaceholderPredicate<'db>

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<'db> PartialEq for StarImportPlaceholderPredicate<'db>

fn eq(&self, other: &StarImportPlaceholderPredicate<'db>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl SalsaStructInDb for StarImportPlaceholderPredicate<'_>

const LEAF_TYPE_IDS: &'static [ConstTypeId]

The type IDs of all concrete (leaf) salsa struct types that this type can contain.

type MemoIngredientMap = MemoIngredientSingletonIndex

fn lookup_ingredient_index(aux: &Zalsa) -> IngredientIndices

Lookup or create ingredient indices.

fn entries(zalsa: &Zalsa) -> impl Iterator<Item = DatabaseKeyIndex> + '_

Returns the IDs of any instances of this struct in the database.

fn cast(id: Id, type_id: TypeId) -> Option<Self>

Plumbing to support nested salsa supertypes.

unsafe fn memo_table( zalsa: &Zalsa, id: Id, current_revision: Revision, ) -> MemoTableWithTypes<'_>

Return the memo table associated with id.

impl SalsaValue for StarImportPlaceholderPredicate<'_>

impl Send for StarImportPlaceholderPredicate<'_>

impl<'db> StructuralPartialEq for StarImportPlaceholderPredicate<'db>

impl Sync for StarImportPlaceholderPredicate<'_>

impl TrackedStructInDb for StarImportPlaceholderPredicate<'_>

fn database_key_index(zalsa: &Zalsa, id: Id) -> DatabaseKeyIndex

Converts the identifier for this tracked struct into a DatabaseKeyIndex.