Enum regex_automata::hybrid::dfa::StateSaver

enum StateSaver {
    None,
    ToSave {
        id: LazyStateID,
        state: State,
    },
    Saved(LazyStateID),
}

A simple type that encapsulates the saving of a state ID through a cache clearing.

A state ID can be marked for saving with ToSave, while a state ID can be saved itself with Saved.

Variants

None

An empty state saver. In this case, no states (other than the special sentinel states) are preserved after clearing the cache.

ToSave

An ID of a state (and the state itself) that should be preserved after the lazy DFA’s cache has been cleared. After clearing, the updated ID is stored in ‘Saved’ since it may have changed.

Fields

id: LazyStateID

state: State

Saved(LazyStateID)

An ID that of a state that has been persisted through a lazy DFA cache clearing. The ID recorded here corresponds to an ID that was once marked as ToSave. The IDs are likely not equivalent even though the states they point to are.

Implementations

impl StateSaver

fn none() -> StateSaver

Create an empty state saver.

fn take_to_save(&mut self) -> Option<(LazyStateID, State)>

Replace this state saver with an empty saver, and if this saver is a request to save a state, return that request.

fn take_saved(&mut self) -> Option<LazyStateID>

Replace this state saver with an empty saver, and if this saver is a saved state (or a request to save a state), return that state’s ID.

The idea here is that a request to save a state isn’t necessarily honored because it might not be needed. e.g., Some higher level code might request a state to be saved on the off chance that the cache gets cleared when a new state is added at a lower level. But if that new state is never added, then the cache is never cleared and the state and its ID remain unchanged.

Trait Implementations

impl Clone for StateSaver

fn clone(&self) -> StateSaver

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for StateSaver

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

Formats the value using the given formatter.