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use std::collections::BTreeSet;
#[derive(Clone, Debug, Default, Eq, PartialEq, Hash)]
pub struct FirstSet {
inner: BTreeSet<char>,
}
impl FirstSet {
pub fn new() -> Self {
Self::default()
}
pub fn of_str(s: &str) -> Self {
let mut inner = BTreeSet::new();
s.chars().next().map(|c| inner.insert(c));
Self { inner }
}
pub fn is_empty(&self) -> bool {
self.inner.is_empty()
}
pub fn union(mut self, mut other: Self) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn intersect(&self, other: &Self) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
}
impl IntoIterator for FirstSet {
type Item = char;
type IntoIter = <BTreeSet<char> as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.inner.into_iter()
}
}
#[derive(Clone, Debug, Default, Eq, PartialEq, Hash)]
pub struct FlastSet {
inner: BTreeSet<char>,
}
impl FlastSet {
pub fn new() -> Self {
Self::default()
}
pub fn is_empty(&self) -> bool {
self.inner.is_empty()
}
pub fn union_first(mut self, mut other: FirstSet) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn union(mut self, mut other: Self) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn intersect_first(&self, other: &FirstSet) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
pub fn intersect(&self, other: &Self) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
}
impl IntoIterator for FlastSet {
type Item = char;
type IntoIter = <BTreeSet<char> as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.inner.into_iter()
}
}
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