use crate::algorithms::factor_weight::FactorIterator;
use crate::semirings::{
StringWeightLeft, StringWeightRestrict, StringWeightRight, StringWeightVariant,
};
#[derive(Debug, PartialEq, Clone)]
pub struct StringFactorLeft {
weight: StringWeightLeft,
done: bool,
}
#[derive(Debug, PartialEq, Clone)]
pub struct StringFactorRight {
weight: StringWeightRight,
done: bool,
}
#[derive(Debug, PartialEq, Clone)]
pub struct StringFactorRestrict {
weight: StringWeightRestrict,
done: bool,
}
macro_rules! impl_string_factor {
($factor: ident, $semiring: ident) => {
impl Iterator for $factor {
type Item = ($semiring, $semiring);
fn next(&mut self) -> Option<Self::Item> {
if self.done() {
return None;
}
let l = self.weight.value.unwrap_labels();
let l1 = vec![l[0]];
let l2: Vec<_> = l.iter().skip(1).cloned().collect();
self.done = true;
Some((l1.into(), l2.into()))
}
}
impl FactorIterator<$semiring> for $factor {
fn new(weight: $semiring) -> Self {
let done = match &weight.value {
StringWeightVariant::Infinity => true,
StringWeightVariant::Labels(l) => (l.len() == 0),
};
Self { weight, done }
}
fn done(&self) -> bool {
self.done
}
}
};
}
impl_string_factor!(StringFactorLeft, StringWeightLeft);
impl_string_factor!(StringFactorRight, StringWeightRight);
impl_string_factor!(StringFactorRestrict, StringWeightRestrict);