Trait rustfst::fst_traits::MutableFst

source · 
pub trait MutableFst: CoreFst + for<'a> MutableArcIterator<'a> {
    fn new() -> Self;
    fn set_start(&mut self, state_id: &StateId) -> Result<(), Error>;
    fn set_final(
        &mut self,
        state_id: &StateId,
        final_weight: <Self as CoreFst>::W
    ) -> Result<(), Error>;
    fn add_state(&mut self) -> StateId;
    fn del_state(&mut self, state_id: &StateId) -> Result<(), Error>;
    fn del_states<T: IntoIterator<Item = StateId>>(
        &mut self,
        states: T
    ) -> Result<(), Error>;
    fn add_arc(
        &mut self,
        source: &StateId,
        arc: Arc<<Self as CoreFst>::W>
    ) -> Result<(), Error>;

    fn add_fst<F: ExpandedFst<W = Self::W>>(
        &mut self,
        fst_to_add: &F
    ) -> Result<HashMap<StateId, StateId>, Error> { ... }
}
Expand description

Trait defining the methods to modify a wFST

Required Methods

Creates an empty wFST

The state with identifier state_id is now the start state. Note that only one start state is allowed in this implementation. Calling this function twice will mean losing the first start state. If the state_id doesn’t exist an error is raised.

use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};
use rustfst::arc::Arc;

let mut fst = VectorFst::<BooleanWeight>::new();
let s1 = fst.add_state();
let s2 = fst.add_state();

assert_eq!(fst.start(), None);

fst.set_start(&s1);
assert_eq!(fst.start(), Some(s1));

fst.set_start(&s2);
assert_eq!(fst.start(), Some(s2));

The state with identifier state_id is now a final state with a weight final_weight. If the state_id doesn’t exist an error is raised.

use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};
use rustfst::arc::Arc;

let mut fst = VectorFst::<BooleanWeight>::new();
let s1 = fst.add_state();
let s2 = fst.add_state();

assert_eq!(fst.final_weight(&s1), None);
assert_eq!(fst.final_weight(&s2), None);

fst.set_final(&s1, BooleanWeight::one());
assert_eq!(fst.final_weight(&s1), Some(BooleanWeight::one()));
assert_eq!(fst.final_weight(&s2), None);

fst.set_final(&s2, BooleanWeight::one());
assert_eq!(fst.final_weight(&s1), Some(BooleanWeight::one()));
assert_eq!(fst.final_weight(&s2), Some(BooleanWeight::one()));

Adds a new state to the current FST. The identifier of the new state is returned

Example
use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};

let mut fst = VectorFst::<BooleanWeight>::new();

assert_eq!(fst.num_states(), 0);

fst.add_state();
assert_eq!(fst.num_states(), 1);

fst.add_state();
assert_eq!(fst.num_states(), 2);

Removes a state from an FST. It also removes all the arcs starting from another state and reaching this state. An error is raised if the state state_id doesn’t exist.

Example
use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst, StateIterator};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};

let mut fst = VectorFst::<BooleanWeight>::new();

assert_eq!(fst.states_iter().count(), 0);

let s1 = fst.add_state();

assert_eq!(fst.states_iter().count(), 1);

fst.del_state(&s1);

assert_eq!(fst.states_iter().count(), 0);

Removes multiple states from an FST. If one of the states doesn’t exist, an error is raised.

Warning

This method modifies the id of the states that are left in the FST. Id that were used before calling this function should no longer be used.

Example
use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst, StateIterator};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};

let mut fst = VectorFst::<BooleanWeight>::new();

assert_eq!(fst.states_iter().count(), 0);

let s1 = fst.add_state();
let s2 = fst.add_state();

assert_eq!(fst.states_iter().count(), 2);

let states_to_remove = vec![s1, s2];
fst.del_states(states_to_remove.into_iter());

assert_eq!(fst.states_iter().count(), 0);

Adds an arc to the FST. The arc will start in the state source. An error is raised if the state source doesn’t exist.

Warning

This method modifies the id of the states that are left in the FST. Id that were used before calling this function should no longer be used.

Example
use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
use rustfst::fst_impls::VectorFst;
use rustfst::semirings::{BooleanWeight, Semiring};
use rustfst::arc::Arc;

let mut fst = VectorFst::<BooleanWeight>::new();
let s1 = fst.add_state();
let s2 = fst.add_state();

assert_eq!(fst.num_arcs(), 0);
fst.add_arc(&s1, Arc::new(3, 5, BooleanWeight::new(true), s2));
assert_eq!(fst.num_arcs(), 1);

Provided Methods

Implementors