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use anyhow::Result;
use crate::semirings::{CompleteSemiring, ReverseBack, Semiring, SemiringProperties, StarSemiring};
use std::borrow::Borrow;
#[derive(Clone, Debug, PartialEq, PartialOrd, Default, Eq, Copy, Hash)]
pub struct BooleanWeight {
value: bool,
}
impl Semiring for BooleanWeight {
type Type = bool;
type ReverseWeight = BooleanWeight;
fn zero() -> Self {
Self { value: false }
}
fn one() -> Self {
Self { value: true }
}
fn new(value: <Self as Semiring>::Type) -> Self {
BooleanWeight { value }
}
fn plus_assign<P: Borrow<Self>>(&mut self, rhs: P) -> Result<()> {
self.value |= rhs.borrow().value;
Ok(())
}
fn times_assign<P: Borrow<Self>>(&mut self, rhs: P) -> Result<()> {
self.value &= rhs.borrow().value;
Ok(())
}
fn value(&self) -> &Self::Type {
&self.value
}
fn take_value(self) -> Self::Type {
self.value
}
fn set_value(&mut self, value: <Self as Semiring>::Type) {
self.value = value
}
fn reverse(&self) -> Result<Self::ReverseWeight> {
Ok(*self)
}
fn properties() -> SemiringProperties {
SemiringProperties::LEFT_SEMIRING
| SemiringProperties::RIGHT_SEMIRING
| SemiringProperties::COMMUTATIVE
| SemiringProperties::IDEMPOTENT
| SemiringProperties::PATH
}
}
impl ReverseBack<BooleanWeight> for BooleanWeight {
fn reverse_back(&self) -> Result<BooleanWeight> {
Ok(*self)
}
}
display_semiring!(BooleanWeight);
impl CompleteSemiring for BooleanWeight {}
impl StarSemiring for BooleanWeight {
fn closure(&self) -> Self {
Self::new(true)
}
}
impl Into<BooleanWeight> for bool {
fn into(self) -> BooleanWeight {
BooleanWeight::new(self)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_boolean_weight() -> Result<()> {
let b_true = BooleanWeight::new(true);
let b_false = BooleanWeight::new(false);
assert_eq!(b_true.plus(&b_true)?, b_true);
assert_eq!(b_true.plus(&b_false)?, b_true);
assert_eq!(b_false.plus(&b_true)?, b_true);
assert_eq!(b_false.plus(&b_false)?, b_false);
assert_eq!(b_true.times(&b_true)?, b_true);
assert_eq!(b_true.times(&b_false)?, b_false);
assert_eq!(b_false.times(&b_true)?, b_false);
assert_eq!(b_false.times(&b_false)?, b_false);
Ok(())
}
}