Struct rustc_data_structures::unify::UnificationTable

pub struct UnificationTable<S>
where
    S: UnificationStoreBase,
{
    values: S,
}

Table of unification keys and their values. You must define a key type K that implements the UnifyKey trait. Unification tables can be used in two-modes:

• in-place (UnificationTable<InPlace<K>> or InPlaceUnificationTable<K>):
  • This is the standard mutable mode, where the array is modified in place.
  • To do backtracking, you can employ the snapshot and rollback_to methods.
• persistent (UnificationTable<Persistent<K>> or PersistentUnificationTable<K>):
  • In this mode, we use a persistent vector to store the data, so that cloning the table is an O(1) operation.
  • This implies that ordinary operations are quite a bit slower though.
  • Requires the persistent feature be selected in your Cargo.toml file.

Fields

values: S

Implementations

impl<K> UnificationTable<InPlace<K, Vec<VarValue<K>>, ()>>

where K: UnifyKey,

pub fn with_log<'a, L>( &'a mut self, undo_log: L, ) -> UnificationTable<InPlace<K, &'a mut Vec<VarValue<K>>, L>>

where L: UndoLogs<UndoLog<Delegate<K>>>,

Creates a UnificationTable using an external undo_log, allowing mutating methods to be called if L does not implement UndoLogs

impl<S> UnificationTable<S>

where S: UnificationStoreBase + Default,

pub fn new() -> UnificationTable<S>

impl<S> UnificationTable<S>

where S: UnificationStore,

pub fn snapshot(&mut self) -> Snapshot<S>

Starts a new snapshot. Each snapshot must be either rolled back or committed in a “LIFO” (stack) order.

pub fn rollback_to(&mut self, snapshot: Snapshot<S>)

Reverses all changes since the last snapshot. Also removes any keys that have been created since then.

pub fn commit(&mut self, snapshot: Snapshot<S>)

Commits all changes since the last snapshot. Of course, they can still be undone if there is a snapshot further out.

pub fn vars_since_snapshot( &self, snapshot: &Snapshot<S>, ) -> Range<<S as UnificationStoreBase>::Key>

Returns the keys of all variables created since the snapshot.

impl<S> UnificationTable<S>

where S: UnificationStoreBase,

pub fn len(&self) -> usize

Returns the number of keys created so far.

impl<S> UnificationTable<S>

where S: UnificationStoreMut,

pub fn new_key( &mut self, value: <S as UnificationStoreBase>::Value, ) -> <S as UnificationStoreBase>::Key

Creates a fresh key with the given value.

pub fn reserve(&mut self, num_new_keys: usize)

Reserve memory for num_new_keys to be created. Does not actually create the new keys; you must then invoke new_key.

pub fn reset_unifications( &mut self, value: impl FnMut(<S as UnificationStoreBase>::Key) -> <S as UnificationStoreBase>::Value, )

Clears all unifications that have been performed, resetting to the initial state. The values of each variable are given by the closure.

impl<S, K, V> UnificationTable<S>

where S: UnificationStoreBase<Key = K, Value = V>, K: UnifyKey<Value = V>, V: UnifyValue,

//////////////////////////////////////////////////////////////////////// Public API

pub fn try_probe_value<'a, K1>(&'a self, id: K1) -> Option<&'a V>

where K1: Into<K>, K: 'a,

Obtains current value for key without any pointer chasing; may return None if key has been union’d.

impl<S, K, V> UnificationTable<S>

where S: UnificationStoreMut<Key = K, Value = V>, K: UnifyKey<Value = V>, V: UnifyValue,

pub fn union<K1, K2>(&mut self, a_id: K1, b_id: K2)

where K1: Into<K>, K2: Into<K>, V: UnifyValue<Error = NoError>,

Unions two keys without the possibility of failure; only applicable when unify values use NoError as their error type.

pub fn union_value<K1>(&mut self, id: K1, value: V)

where K1: Into<K>, V: UnifyValue<Error = NoError>,

Unions a key and a value without the possibility of failure; only applicable when unify values use NoError as their error type.

pub fn unioned<K1, K2>(&mut self, a_id: K1, b_id: K2) -> bool

where K1: Into<K>, K2: Into<K>,

Given two keys, indicates whether they have been unioned together.

pub fn find<K1>(&mut self, id: K1) -> K

where K1: Into<K>,

Given a key, returns the (current) root key.

pub fn unify_var_var<K1, K2>( &mut self, a_id: K1, b_id: K2, ) -> Result<(), <V as UnifyValue>::Error>

where K1: Into<K>, K2: Into<K>,

Unions together two variables, merging their values. If merging the values fails, the error is propagated and this method has no effect.

pub fn unify_var_value<K1>( &mut self, a_id: K1, b: V, ) -> Result<(), <V as UnifyValue>::Error>

where K1: Into<K>,

Sets the value of the key a_id to b, attempting to merge with the previous value.

pub fn probe_value<K1>(&mut self, id: K1) -> V

where K1: Into<K>,

Returns the current value for the given key. If the key has been union’d, this will give the value from the current root.

pub fn inlined_probe_value<K1>(&mut self, id: K1) -> V

where K1: Into<K>,

Trait Implementations

impl<S> Clone for UnificationTable<S>

where S: Clone + UnificationStoreBase,

fn clone(&self) -> UnificationTable<S>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<S> Debug for UnificationTable<S>

where S: Debug + UnificationStoreBase,

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

Formats the value using the given formatter.

impl<S> Default for UnificationTable<S>

where S: Default + UnificationStoreBase,

fn default() -> UnificationTable<S>

Returns the “default value” for a type.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.