use std::fmt::Debug;
use crate::semirings::Semiring;
use crate::Tr;
use crate::EPS_LABEL;
pub trait TrFilter<S: Semiring>: Clone + Debug + PartialEq {
fn keep(&self, tr: &Tr<S>) -> bool;
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct AnyTrFilter {}
impl<S: Semiring> TrFilter<S> for AnyTrFilter {
fn keep(&self, _tr: &Tr<S>) -> bool {
true
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct EpsilonTrFilter {}
impl<S: Semiring> TrFilter<S> for EpsilonTrFilter {
fn keep(&self, tr: &Tr<S>) -> bool {
tr.ilabel == EPS_LABEL && tr.olabel == EPS_LABEL
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct InputEpsilonTrFilter {}
impl<S: Semiring> TrFilter<S> for InputEpsilonTrFilter {
fn keep(&self, tr: &Tr<S>) -> bool {
tr.ilabel == EPS_LABEL
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct OutputEpsilonTrFilter {}
impl<S: Semiring> TrFilter<S> for OutputEpsilonTrFilter {
fn keep(&self, tr: &Tr<S>) -> bool {
tr.olabel == EPS_LABEL
}
}