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use std::marker::PhantomData; use std::sync::Arc; use anyhow::Result; use crate::algorithms::compose::lookahead_matchers::{LookAheadMatcherData, LookaheadMatcher}; use crate::algorithms::compose::matchers::{MatchType, Matcher, MatcherFlags}; use crate::fst_traits::{ExpandedFst, Fst}; use crate::semirings::Semiring; use crate::{Label, StateId, Tr}; #[derive(Debug, Clone)] pub struct TrivialLookAheadMatcher<W, M> { matcher: M, w: PhantomData<W>, } impl<W: Semiring, M: Matcher<W>> Matcher<W> for TrivialLookAheadMatcher<W, M> { type F = M::F; type Iter = M::Iter; fn new(fst: Arc<Self::F>, match_type: MatchType) -> Result<Self> { Ok(Self { matcher: M::new(fst, match_type)?, w: PhantomData, }) } fn iter(&self, state: usize, label: usize) -> Result<Self::Iter> { self.matcher.iter(state, label) } fn final_weight(&self, state: usize) -> Result<Option<W>> { self.matcher.final_weight(state) } fn match_type(&self, test: bool) -> Result<MatchType> { self.matcher.match_type(test) } fn flags(&self) -> MatcherFlags { self.matcher.flags() | MatcherFlags::INPUT_LOOKAHEAD_MATCHER | MatcherFlags::OUTPUT_LOOKAHEAD_MATCHER } fn priority(&self, state: usize) -> Result<usize> { self.matcher.priority(state) } fn fst(&self) -> &Arc<Self::F> { self.matcher.fst() } } impl<W: Semiring, M: Matcher<W>> LookaheadMatcher<W> for TrivialLookAheadMatcher<W, M> { type MatcherData = (); fn data(&self) -> Option<&Arc<Self::MatcherData>> { None } fn new_with_data( fst: Arc<Self::F>, match_type: MatchType, _data: Option<Arc<Self::MatcherData>>, ) -> Result<Self> { Self::new(fst, match_type) } fn create_data<F: ExpandedFst<W>>( _fst: &F, _match_type: MatchType, ) -> Result<Option<Self::MatcherData>> { Ok(None) } fn init_lookahead_fst<LF: ExpandedFst<W>>(&mut self, _lfst: &Arc<LF>) -> Result<()> { Ok(()) } fn lookahead_fst<LF: Fst<W>>( &self, _matcher_state: StateId, _lfst: &Arc<LF>, _s: StateId, ) -> Result<Option<LookAheadMatcherData<W>>> { Ok(Some(LookAheadMatcherData::default())) } fn lookahead_label(&self, _state: StateId, _label: Label) -> Result<bool> { Ok(true) } fn lookahead_prefix( &self, _tr: &mut Tr<W>, _la_matcher_data: &LookAheadMatcherData<W>, ) -> bool { false } }