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use crate::ast::domains::Int;
use num_traits::Num;
use polyquine::Quine;
use serde::{Deserialize, Serialize};
use std::fmt::Display;
#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, Quine)]
#[path_prefix(conjure_cp::ast)]
pub enum Range<A = Int> {
Single(A),
Bounded(A, A),
UnboundedL(A),
UnboundedR(A),
Unbounded,
}
impl<A> Range<A> {
/// Whether the range is **bounded** on either side. A bounded range may still be infinite.
/// See also: [Range::is_finite].
pub fn is_lower_or_upper_bounded(&self) -> bool {
match &self {
Range::Single(_)
| Range::Bounded(_, _)
| Range::UnboundedL(_)
| Range::UnboundedR(_) => true,
Range::Unbounded => false,
/// Whether the range is **unbounded** on both sides.
pub fn is_unbounded(&self) -> bool {
!self.is_lower_or_upper_bounded()
/// Whether the range is **finite**. See also: [Range::is_lower_or_upper_bounded].
pub fn is_finite(&self) -> bool {
Range::Single(_) | Range::Bounded(_, _) => true,
Range::Unbounded | Range::UnboundedL(_) | Range::UnboundedR(_) => false,
impl<A: Ord> Range<A> {
pub fn contains(&self, val: &A) -> bool {
match self {
Range::Single(x) => x == val,
Range::Bounded(x, y) => x <= val && val <= y,
Range::UnboundedR(x) => x <= val,
Range::UnboundedL(x) => val <= x,
Range::Unbounded => true,
/// Returns the lower bound of the range, if it has one
pub fn low(&self) -> Option<&A> {
Range::Single(a) => Some(a),
Range::Bounded(a, _) => Some(a),
Range::UnboundedR(a) => Some(a),
Range::UnboundedL(_) | Range::Unbounded => None,
/// Returns the upper bound of the range, if it has one
pub fn high(&self) -> Option<&A> {
Range::Bounded(_, a) => Some(a),
Range::UnboundedL(a) => Some(a),
Range::UnboundedR(_) | Range::Unbounded => None,
impl<A: Ord + Clone> Range<A> {
/// Create a new range with a lower and upper bound
pub fn new(lo: Option<A>, hi: Option<A>) -> Range<A> {
match (lo, hi) {
(None, None) => Range::Unbounded,
(Some(l), None) => Range::UnboundedR(l),
(None, Some(r)) => Range::UnboundedL(r),
(Some(l), Some(r)) => {
if l == r {
Range::Single(l)
} else {
let min = Ord::min(&l, &r).clone();
let max = Ord::max(l, r);
Range::Bounded(min, max)
/// Given a slice of ranges, create a single range that spans from the start
/// of the leftmost range to the end of the rightmost range.
/// An empty slice is considered equivalent to `Range::unbounded`.
pub fn spanning(rngs: &[Range<A>]) -> Range<A> {
if rngs.is_empty() {
return Range::Unbounded;
let mut lo = rngs[0].low();
let mut hi = rngs[0].high();
for rng in rngs {
lo = match (lo, rng.low()) {
(Some(curr), Some(new)) => Some(curr.min(new)),
_ => None,
};
hi = match (hi, rng.high()) {
(Some(curr), Some(new)) => Some(curr.max(new)),
Range::new(lo.cloned(), hi.cloned())
impl<A: Num + Ord + Clone> Range<A> {
pub fn length(&self) -> Option<A> {
Range::Single(_) => Some(A::one()),
Range::Bounded(i, j) => Some(j.clone() - i.clone() + A::one()),
Range::UnboundedR(_) | Range::UnboundedL(_) | Range::Unbounded => None,
/// Returns true if this interval overlaps another one, i.e. at least one
/// number is part of both `self` and `other`
/// E.g:
/// - [0, 2] overlaps [2, 4]
/// - [1, 3] overlaps [2, 4]
/// - [4, 6] overlaps [2, 4]
pub fn overlaps(&self, other: &Range<A>) -> bool {
self.low()
.is_none_or(|la| other.high().is_none_or(|rb| la <= rb))
&& self
.high()
.is_none_or(|ra| other.low().is_none_or(|lb| ra >= lb))
/// Returns true if this interval touches another one on the left
/// E.g: [1, 2] touches_left [3, 4]
pub fn touches_left(&self, other: &Range<A>) -> bool {
self.high().is_some_and(|ra| {
let ra = ra.clone() + A::one();
other.low().is_some_and(|lb| ra.eq(lb))
})
/// Returns true if this interval touches another one on the right
/// E.g: [3, 4] touches_right [1, 2]
pub fn touches_right(&self, other: &Range<A>) -> bool {
self.low().is_some_and(|la| {
let la = la.clone() - A::one();
other.high().is_some_and(|rb| la.eq(rb))
/// Returns true if this interval overlaps or touches another one
/// - [1, 3] joins [4, 6]
/// - [2, 4] joins [4, 6]
/// - [3, 5] joins [4, 6]
/// - [6, 8] joins [4, 6]
/// - [7, 8] joins [4, 6]
pub fn joins(&self, other: &Range<A>) -> bool {
self.touches_left(other) || self.overlaps(other) || self.touches_right(other)
/// Returns true if this interval is strictly before another one
pub fn is_before(&self, other: &Range<A>) -> bool {
self.high()
.is_some_and(|ra| other.low().is_some_and(|lb| ra < &(lb.clone() - A::one())))
/// Returns true if this interval is strictly after another one
pub fn is_after(&self, other: &Range<A>) -> bool {
.is_some_and(|la| other.high().is_some_and(|rb| la > &(rb.clone() + A::one())))
/// If the two ranges join, return a new range which spans both
pub fn join(&self, other: &Range<A>) -> Option<Range<A>> {
if self.joins(other) {
let lo = Ord::min(self.low(), other.low());
let hi = Ord::max(self.high(), other.high());
return Some(Range::new(lo.cloned(), hi.cloned()));
None
/// Merge all joining ranges in the list, and return a new vec of disjoint ranges.
/// ```ignore
/// [(2..3), (4), (..1), (6..8)] -> [(..4), (6..8)]
/// ```
///
/// # Performance
/// Currently uses a naive O(n^2) algorithm.
/// A more optimal approach based on interval trees is planned.
pub fn squeeze(rngs: &[Range<A>]) -> Vec<Range<A>> {
let mut ans = Vec::from(rngs);
if ans.is_empty() {
return ans;
loop {
let mut merged = false;
// Check every pair of ranges and join them if possible
'outer: for i in 0..ans.len() {
for j in (i + 1)..ans.len() {
if let Some(joined) = ans[i].join(&ans[j]) {
ans[i] = joined;
// Safe to delete here because we restart the outer loop immediately
ans.remove(j);
merged = true;
break 'outer;
// If no merges occurred, we're done
if !merged {
break;
ans
/// If this range is bounded, returns a lazy iterator over all values within the range.
/// Otherwise, returns None.
pub fn iter(&self) -> Option<RangeIterator<A>> {
Range::Single(val) => Some(RangeIterator::Single(Some(val.clone()))),
Range::Bounded(start, end) => Some(RangeIterator::Bounded {
current: start.clone(),
end: end.clone(),
}),
Range::UnboundedL(_) | Range::UnboundedR(_) | Range::Unbounded => None,
pub fn values(rngs: &[Range<A>]) -> Option<impl Iterator<Item = A>> {
let itrs = rngs
.iter()
.map(Range::iter)
.collect::<Option<Vec<RangeIterator<A>>>>()?;
Some(itrs.into_iter().flatten())
/// Iterator for Range<A> that yields values lazily
pub enum RangeIterator<A> {
Single(Option<A>),
Bounded { current: A, end: A },
impl<A: Num + Ord + Clone> Iterator for RangeIterator<A> {
type Item = A;
fn next(&mut self) -> Option<Self::Item> {
RangeIterator::Single(val) => val.take(),
RangeIterator::Bounded { current, end } => {
if current > end {
return None;
let result = current.clone();
*current = current.clone() + A::one();
Some(result)
impl<A: Display> Display for Range<A> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
Range::Single(i) => write!(f, "{i}"),
Range::Bounded(i, j) => write!(f, "{i}..{j}"),
Range::UnboundedR(i) => write!(f, "{i}.."),
Range::UnboundedL(i) => write!(f, "..{i}"),
Range::Unbounded => write!(f, ""),
#[allow(unused_imports)]
mod test {
use super::*;
use crate::range;
#[test]
pub fn test_range_macros() {
assert_eq!(range!(1..3), Range::Bounded(1, 3));
assert_eq!(range!(1..), Range::UnboundedR(1));
assert_eq!(range!(..3), Range::UnboundedL(3));
assert_eq!(range!(1), Range::Single(1));
pub fn test_range_low() {
assert_eq!(range!(1..3).low(), Some(&1));
assert_eq!(range!(1..).low(), Some(&1));
assert_eq!(range!(1).low(), Some(&1));
assert_eq!(range!(..3).low(), None);
assert_eq!(Range::<Int>::Unbounded.low(), None);
pub fn test_range_high() {
assert_eq!(range!(1..3).high(), Some(&3));
assert_eq!(range!(1..).high(), None);
assert_eq!(range!(1).high(), Some(&1));
assert_eq!(range!(..3).high(), Some(&3));
assert_eq!(Range::<Int>::Unbounded.high(), None);
pub fn test_range_is_finite() {
assert!(range!(1..3).is_finite());
assert!(range!(1).is_finite());
assert!(!range!(1..).is_finite());
assert!(!range!(..3).is_finite());
assert!(!Range::<Int>::Unbounded.is_finite());
pub fn test_range_bounded() {
assert!(range!(1..3).is_lower_or_upper_bounded());
assert!(range!(1).is_lower_or_upper_bounded());
assert!(range!(1..).is_lower_or_upper_bounded());
assert!(range!(..3).is_lower_or_upper_bounded());
assert!(!Range::<Int>::Unbounded.is_lower_or_upper_bounded());
pub fn test_range_length() {
assert_eq!(range!(1..3).length(), Some(3));
assert_eq!(range!(1).length(), Some(1));
assert_eq!(range!(1..).length(), None);
assert_eq!(range!(..3).length(), None);
assert_eq!(Range::<Int>::Unbounded.length(), None);
pub fn test_range_contains_value() {
assert!(range!(1..3).contains(&2));
assert!(!range!(1..3).contains(&4));
assert!(range!(1).contains(&1));
assert!(!range!(1).contains(&2));
assert!(Range::Unbounded.contains(&42));
pub fn test_range_overlaps() {
assert!(range!(1..3).overlaps(&range!(2..4)));
assert!(range!(1..3).overlaps(&range!(3..5)));
assert!(!range!(1..3).overlaps(&range!(4..6)));
assert!(Range::Unbounded.overlaps(&range!(1..3)));
pub fn test_range_touches_left() {
assert!(range!(1..2).touches_left(&range!(3..4)));
assert!(range!(1..2).touches_left(&range!(3)));
assert!(range!(-5..-4).touches_left(&range!(-3..2)));
assert!(!range!(1..2).touches_left(&range!(4..5)));
assert!(!range!(1..2).touches_left(&range!(2..3)));
assert!(!range!(3..4).touches_left(&range!(1..2)));
pub fn test_range_touches_right() {
assert!(range!(3..4).touches_right(&range!(1..2)));
assert!(range!(3).touches_right(&range!(1..2)));
assert!(range!(0..1).touches_right(&range!(-2..-1)));
assert!(!range!(1..2).touches_right(&range!(3..4)));
assert!(!range!(2..3).touches_right(&range!(1..2)));
assert!(!range!(1..2).touches_right(&range!(1..2)));
pub fn test_range_is_before() {
assert!(range!(1..2).is_before(&range!(4..5)));
assert!(range!(1..2).is_before(&range!(4..)));
assert!(!range!(1..2).is_before(&range!(3..)));
assert!(!range!(1..2).is_before(&range!(..4)));
assert!(!range!(1..2).is_before(&range!(2..4)));
assert!(!range!(3..4).is_before(&range!(1..2)));
assert!(!range!(1..2).is_before(&Range::Unbounded));
pub fn test_range_is_after() {
assert!(range!(5..6).is_after(&range!(1..2)));
assert!(range!(4..5).is_after(&range!(..2)));
assert!(!range!(4..5).is_after(&range!(..3)));
assert!(!range!(2..3).is_after(&range!(1..2)));
assert!(!range!(1..2).is_after(&range!(3..4)));
assert!(!range!(1..2).is_after(&Range::Unbounded));
pub fn test_range_squeeze() {
let input = vec![range!(2..3), range!(4), range!(..1), range!(6..8)];
let squeezed = Range::squeeze(&input);
assert_eq!(squeezed, vec![range!(..4), range!(6..8)]);
pub fn test_range_spanning() {
assert_eq!(Range::<Int>::spanning(&[]), Range::Unbounded);
assert_eq!(Range::spanning(&[range!(1..2), range!(4..5)]), range!(1..5));
assert_eq!(
Range::spanning(&[range!(..0), range!(2..4)]),
Range::UnboundedL(4)
);
Range::spanning(&[range!(0), range!(2..3), range!(5..)]),
Range::UnboundedR(0)
Range::spanning(&[range!(..0), range!(2..)]),
Range::Unbounded