Trait rustfst::fst_traits::CoreFst

source · 
pub trait CoreFst {
    type W: Semiring;

    fn start(&self) -> Option<StateId>;
    fn final_weight(&self, _: &StateId) -> Option<<Self as CoreFst>::W>;
    fn num_arcs(&self) -> usize;

    fn is_final(&self, state_id: &StateId) -> bool { ... }
}
Expand description

Trait defining necessary methods for a wFST to access start states and final states

Required Associated Types

Weight use in the wFST. This type must implement the Semiring trait

Required Methods

Returns the ID of the start state of the wFST if it exists else none.

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

// 1 - Create an FST
let mut fst = VectorFst::<BooleanWeight>::new();
let s = fst.add_state();
fst.set_start(&s);

// 2 - Access the start state
let start_state = fst.start();
assert_eq!(start_state, Some(s));

Retrieves the final weight of a state (if the state is a final one).

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

// 1 - Create an FST
let mut fst = VectorFst::<BooleanWeight>::new();
let s1 = fst.add_state();
let s2 = fst.add_state();
fst.set_final(&s2, BooleanWeight::one());

// 2 - Access the final weight of each state
assert_eq!(fst.final_weight(&s1), None);
assert_eq!(fst.final_weight(&s2), Some(BooleanWeight::one()));

Total number of arcs in the wFST. This is the sum of the outgoing arcs of each state.

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

Returns whether or not the state with identifier passed as parameters is a final state.

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

// 1 - Create an FST
let mut fst = VectorFst::<BooleanWeight>::new();
let s1 = fst.add_state();
let s2 = fst.add_state();
fst.set_final(&s2, BooleanWeight::one());

// 2 - Test if a state is final
assert!(!fst.is_final(&s1));
assert!(fst.is_final(&s2));

Implementors