Struct DefaultComposeFilter 

pub struct DefaultComposeFilter;

Default composition filter implementing standard label matching.

This filter matches arcs when arc1.olabel == arc2.ilabel, handling epsilon transitions by allowing them to match any label. The composed arc takes ilabel from arc1 and olabel from arc2.

Epsilon Handling

• Epsilon output from FST1 (arc1.olabel == 0) matches any FST2 input
• Epsilon input in FST2 (arc2.ilabel == 0) matches any FST1 output
• Both epsilon: composed arc is epsilon

Example

use arcweight::prelude::*;

let mut fst1 = VectorFst::<TropicalWeight>::new();
let s0 = fst1.add_state();
let s1 = fst1.add_state();
fst1.set_start(s0);
fst1.set_final(s1, TropicalWeight::one());
fst1.add_arc(s0, Arc::new(1, 2, TropicalWeight::new(0.5), s1));

let mut fst2 = VectorFst::<TropicalWeight>::new();
let t0 = fst2.add_state();
let t1 = fst2.add_state();
fst2.set_start(t0);
fst2.set_final(t1, TropicalWeight::one());
fst2.add_arc(t0, Arc::new(2, 3, TropicalWeight::new(0.3), t1));

// Compose using default filter
let result: VectorFst<TropicalWeight> = compose_default(&fst1, &fst2)?;

Trait Implementations

impl Clone for DefaultComposeFilter

fn clone(&self) -> DefaultComposeFilter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<W: Semiring> ComposeFilter<W> for DefaultComposeFilter

type FilterState = ()

Associated state type for tracking filter context across transitions.

fn start() -> Self::FilterState

Returns the initial filter state for composition start.

fn filter_arc( &self, arc1: &Arc<W>, arc2: &Arc<W>, _fs: &Self::FilterState, ) -> Option<(Arc<W>, Self::FilterState)>

Determines if two arcs can be composed and returns the resulting arc.

impl Copy for DefaultComposeFilter

impl Debug for DefaultComposeFilter

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

Formats the value using the given formatter.

impl Default for DefaultComposeFilter

fn default() -> DefaultComposeFilter

Returns the “default value” for a type.