1//! # Experimental replacement range types
2//!
3//! The types within this module are meant to replace the existing
4//! `Range`, `RangeInclusive`, and `RangeFrom` types in a future edition.
5//!
6//! ```
7//! #![feature(new_range_api)]
8//! use core::range::{Range, RangeFrom, RangeInclusive};
9//!
10//! let arr = [0, 1, 2, 3, 4];
11//! assert_eq!(arr[ .. ], [0, 1, 2, 3, 4]);
12//! assert_eq!(arr[ .. 3 ], [0, 1, 2 ]);
13//! assert_eq!(arr[ ..=3 ], [0, 1, 2, 3 ]);
14//! assert_eq!(arr[ RangeFrom::from(1.. )], [ 1, 2, 3, 4]);
15//! assert_eq!(arr[ Range::from(1..3 )], [ 1, 2 ]);
16//! assert_eq!(arr[RangeInclusive::from(1..=3)], [ 1, 2, 3 ]);
17//! ```
18
19use crate::fmt;
20use crate::hash::Hash;
21
22mod iter;
23
24#[unstable(feature = "new_range_api", issue = "125687")]
25pub mod legacy;
26
27use Bound::{Excluded, Included, Unbounded};
28#[doc(inline)]
29pub use iter::{IterRange, IterRangeFrom, IterRangeInclusive};
30
31#[doc(inline)]
32pub use crate::iter::Step;
33#[doc(inline)]
34pub use crate::ops::{
35 Bound, IntoBounds, OneSidedRange, RangeBounds, RangeFull, RangeTo, RangeToInclusive,
36};
37
38/// A (half-open) range bounded inclusively below and exclusively above
39/// (`start..end` in a future edition).
40///
41/// The range `start..end` contains all values with `start <= x < end`.
42/// It is empty if `start >= end`.
43///
44/// # Examples
45///
46/// ```
47/// #![feature(new_range_api)]
48/// use core::range::Range;
49///
50/// assert_eq!(Range::from(3..5), Range { start: 3, end: 5 });
51/// assert_eq!(3 + 4 + 5, Range::from(3..6).into_iter().sum());
52/// ```
53#[lang = "RangeCopy"]
54#[derive(Clone, Copy, Default, PartialEq, Eq, Hash)]
55#[unstable(feature = "new_range_api", issue = "125687")]
56pub struct Range<Idx> {
57 /// The lower bound of the range (inclusive).
58 #[unstable(feature = "new_range_api", issue = "125687")]
59 pub start: Idx,
60 /// The upper bound of the range (exclusive).
61 #[unstable(feature = "new_range_api", issue = "125687")]
62 pub end: Idx,
63}
64
65#[unstable(feature = "new_range_api", issue = "125687")]
66impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
67 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
68 self.start.fmt(fmt)?;
69 write!(fmt, "..")?;
70 self.end.fmt(fmt)?;
71 Ok(())
72 }
73}
74
75impl<Idx: Step> Range<Idx> {
76 /// Creates an iterator over the elements within this range.
77 ///
78 /// Shorthand for `.clone().into_iter()`
79 ///
80 /// # Examples
81 ///
82 /// ```
83 /// #![feature(new_range_api)]
84 /// use core::range::Range;
85 ///
86 /// let mut i = Range::from(3..9).iter().map(|n| n*n);
87 /// assert_eq!(i.next(), Some(9));
88 /// assert_eq!(i.next(), Some(16));
89 /// assert_eq!(i.next(), Some(25));
90 /// ```
91 #[unstable(feature = "new_range_api", issue = "125687")]
92 #[inline]
93 pub fn iter(&self) -> IterRange<Idx> {
94 self.clone().into_iter()
95 }
96}
97
98impl<Idx: PartialOrd<Idx>> Range<Idx> {
99 /// Returns `true` if `item` is contained in the range.
100 ///
101 /// # Examples
102 ///
103 /// ```
104 /// #![feature(new_range_api)]
105 /// use core::range::Range;
106 ///
107 /// assert!(!Range::from(3..5).contains(&2));
108 /// assert!( Range::from(3..5).contains(&3));
109 /// assert!( Range::from(3..5).contains(&4));
110 /// assert!(!Range::from(3..5).contains(&5));
111 ///
112 /// assert!(!Range::from(3..3).contains(&3));
113 /// assert!(!Range::from(3..2).contains(&3));
114 ///
115 /// assert!( Range::from(0.0..1.0).contains(&0.5));
116 /// assert!(!Range::from(0.0..1.0).contains(&f32::NAN));
117 /// assert!(!Range::from(0.0..f32::NAN).contains(&0.5));
118 /// assert!(!Range::from(f32::NAN..1.0).contains(&0.5));
119 /// ```
120 #[inline]
121 #[unstable(feature = "new_range_api", issue = "125687")]
122 pub fn contains<U>(&self, item: &U) -> bool
123 where
124 Idx: PartialOrd<U>,
125 U: ?Sized + PartialOrd<Idx>,
126 {
127 <Self as RangeBounds<Idx>>::contains(self, item)
128 }
129
130 /// Returns `true` if the range contains no items.
131 ///
132 /// # Examples
133 ///
134 /// ```
135 /// #![feature(new_range_api)]
136 /// use core::range::Range;
137 ///
138 /// assert!(!Range::from(3..5).is_empty());
139 /// assert!( Range::from(3..3).is_empty());
140 /// assert!( Range::from(3..2).is_empty());
141 /// ```
142 ///
143 /// The range is empty if either side is incomparable:
144 ///
145 /// ```
146 /// #![feature(new_range_api)]
147 /// use core::range::Range;
148 ///
149 /// assert!(!Range::from(3.0..5.0).is_empty());
150 /// assert!( Range::from(3.0..f32::NAN).is_empty());
151 /// assert!( Range::from(f32::NAN..5.0).is_empty());
152 /// ```
153 #[inline]
154 #[unstable(feature = "new_range_api", issue = "125687")]
155 pub fn is_empty(&self) -> bool {
156 !(self.start < self.end)
157 }
158}
159
160#[unstable(feature = "new_range_api", issue = "125687")]
161impl<T> RangeBounds<T> for Range<T> {
162 fn start_bound(&self) -> Bound<&T> {
163 Included(&self.start)
164 }
165 fn end_bound(&self) -> Bound<&T> {
166 Excluded(&self.end)
167 }
168}
169
170#[unstable(feature = "new_range_api", issue = "125687")]
171impl<T> RangeBounds<T> for Range<&T> {
172 fn start_bound(&self) -> Bound<&T> {
173 Included(self.start)
174 }
175 fn end_bound(&self) -> Bound<&T> {
176 Excluded(self.end)
177 }
178}
179
180// #[unstable(feature = "range_into_bounds", issue = "136903")]
181#[unstable(feature = "new_range_api", issue = "125687")]
182impl<T> IntoBounds<T> for Range<T> {
183 fn into_bounds(self) -> (Bound<T>, Bound<T>) {
184 (Included(self.start), Excluded(self.end))
185 }
186}
187
188#[unstable(feature = "new_range_api", issue = "125687")]
189impl<T> From<Range<T>> for legacy::Range<T> {
190 #[inline]
191 fn from(value: Range<T>) -> Self {
192 Self { start: value.start, end: value.end }
193 }
194}
195#[unstable(feature = "new_range_api", issue = "125687")]
196impl<T> From<legacy::Range<T>> for Range<T> {
197 #[inline]
198 fn from(value: legacy::Range<T>) -> Self {
199 Self { start: value.start, end: value.end }
200 }
201}
202
203/// A range bounded inclusively below and above (`start..=end`).
204///
205/// The `RangeInclusive` `start..=end` contains all values with `x >= start`
206/// and `x <= end`. It is empty unless `start <= end`.
207///
208/// # Examples
209///
210/// The `start..=end` syntax is a `RangeInclusive`:
211///
212/// ```
213/// #![feature(new_range_api)]
214/// use core::range::RangeInclusive;
215///
216/// assert_eq!(RangeInclusive::from(3..=5), RangeInclusive { start: 3, end: 5 });
217/// assert_eq!(3 + 4 + 5, RangeInclusive::from(3..=5).into_iter().sum());
218/// ```
219#[lang = "RangeInclusiveCopy"]
220#[derive(Clone, Copy, PartialEq, Eq, Hash)]
221#[unstable(feature = "new_range_api", issue = "125687")]
222pub struct RangeInclusive<Idx> {
223 /// The lower bound of the range (inclusive).
224 #[unstable(feature = "new_range_api", issue = "125687")]
225 pub start: Idx,
226 /// The upper bound of the range (inclusive).
227 #[unstable(feature = "new_range_api", issue = "125687")]
228 pub end: Idx,
229}
230
231#[unstable(feature = "new_range_api", issue = "125687")]
232impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
233 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
234 self.start.fmt(fmt)?;
235 write!(fmt, "..=")?;
236 self.end.fmt(fmt)?;
237 Ok(())
238 }
239}
240
241impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
242 /// Returns `true` if `item` is contained in the range.
243 ///
244 /// # Examples
245 ///
246 /// ```
247 /// #![feature(new_range_api)]
248 /// use core::range::RangeInclusive;
249 ///
250 /// assert!(!RangeInclusive::from(3..=5).contains(&2));
251 /// assert!( RangeInclusive::from(3..=5).contains(&3));
252 /// assert!( RangeInclusive::from(3..=5).contains(&4));
253 /// assert!( RangeInclusive::from(3..=5).contains(&5));
254 /// assert!(!RangeInclusive::from(3..=5).contains(&6));
255 ///
256 /// assert!( RangeInclusive::from(3..=3).contains(&3));
257 /// assert!(!RangeInclusive::from(3..=2).contains(&3));
258 ///
259 /// assert!( RangeInclusive::from(0.0..=1.0).contains(&1.0));
260 /// assert!(!RangeInclusive::from(0.0..=1.0).contains(&f32::NAN));
261 /// assert!(!RangeInclusive::from(0.0..=f32::NAN).contains(&0.0));
262 /// assert!(!RangeInclusive::from(f32::NAN..=1.0).contains(&1.0));
263 /// ```
264 #[inline]
265 #[unstable(feature = "new_range_api", issue = "125687")]
266 pub fn contains<U>(&self, item: &U) -> bool
267 where
268 Idx: PartialOrd<U>,
269 U: ?Sized + PartialOrd<Idx>,
270 {
271 <Self as RangeBounds<Idx>>::contains(self, item)
272 }
273
274 /// Returns `true` if the range contains no items.
275 ///
276 /// # Examples
277 ///
278 /// ```
279 /// #![feature(new_range_api)]
280 /// use core::range::RangeInclusive;
281 ///
282 /// assert!(!RangeInclusive::from(3..=5).is_empty());
283 /// assert!(!RangeInclusive::from(3..=3).is_empty());
284 /// assert!( RangeInclusive::from(3..=2).is_empty());
285 /// ```
286 ///
287 /// The range is empty if either side is incomparable:
288 ///
289 /// ```
290 /// #![feature(new_range_api)]
291 /// use core::range::RangeInclusive;
292 ///
293 /// assert!(!RangeInclusive::from(3.0..=5.0).is_empty());
294 /// assert!( RangeInclusive::from(3.0..=f32::NAN).is_empty());
295 /// assert!( RangeInclusive::from(f32::NAN..=5.0).is_empty());
296 /// ```
297 #[unstable(feature = "new_range_api", issue = "125687")]
298 #[inline]
299 pub fn is_empty(&self) -> bool {
300 !(self.start <= self.end)
301 }
302}
303
304impl<Idx: Step> RangeInclusive<Idx> {
305 /// Creates an iterator over the elements within this range.
306 ///
307 /// Shorthand for `.clone().into_iter()`
308 ///
309 /// # Examples
310 ///
311 /// ```
312 /// #![feature(new_range_api)]
313 /// use core::range::RangeInclusive;
314 ///
315 /// let mut i = RangeInclusive::from(3..=8).iter().map(|n| n*n);
316 /// assert_eq!(i.next(), Some(9));
317 /// assert_eq!(i.next(), Some(16));
318 /// assert_eq!(i.next(), Some(25));
319 /// ```
320 #[unstable(feature = "new_range_api", issue = "125687")]
321 #[inline]
322 pub fn iter(&self) -> IterRangeInclusive<Idx> {
323 self.clone().into_iter()
324 }
325}
326
327impl RangeInclusive<usize> {
328 /// Converts to an exclusive `Range` for `SliceIndex` implementations.
329 /// The caller is responsible for dealing with `end == usize::MAX`.
330 #[inline]
331 pub(crate) const fn into_slice_range(self) -> Range<usize> {
332 Range { start: self.start, end: self.end + 1 }
333 }
334}
335
336#[unstable(feature = "new_range_api", issue = "125687")]
337impl<T> RangeBounds<T> for RangeInclusive<T> {
338 fn start_bound(&self) -> Bound<&T> {
339 Included(&self.start)
340 }
341 fn end_bound(&self) -> Bound<&T> {
342 Included(&self.end)
343 }
344}
345
346#[unstable(feature = "new_range_api", issue = "125687")]
347impl<T> RangeBounds<T> for RangeInclusive<&T> {
348 fn start_bound(&self) -> Bound<&T> {
349 Included(self.start)
350 }
351 fn end_bound(&self) -> Bound<&T> {
352 Included(self.end)
353 }
354}
355
356// #[unstable(feature = "range_into_bounds", issue = "136903")]
357#[unstable(feature = "new_range_api", issue = "125687")]
358impl<T> IntoBounds<T> for RangeInclusive<T> {
359 fn into_bounds(self) -> (Bound<T>, Bound<T>) {
360 (Included(self.start), Included(self.end))
361 }
362}
363
364#[unstable(feature = "new_range_api", issue = "125687")]
365impl<T> From<RangeInclusive<T>> for legacy::RangeInclusive<T> {
366 #[inline]
367 fn from(value: RangeInclusive<T>) -> Self {
368 Self::new(value.start, value.end)
369 }
370}
371#[unstable(feature = "new_range_api", issue = "125687")]
372impl<T> From<legacy::RangeInclusive<T>> for RangeInclusive<T> {
373 #[inline]
374 fn from(value: legacy::RangeInclusive<T>) -> Self {
375 assert!(
376 !value.exhausted,
377 "attempted to convert from an exhausted `legacy::RangeInclusive` (unspecified behavior)"
378 );
379
380 let (start: T, end: T) = value.into_inner();
381 RangeInclusive { start, end }
382 }
383}
384
385/// A range only bounded inclusively below (`start..`).
386///
387/// The `RangeFrom` `start..` contains all values with `x >= start`.
388///
389/// *Note*: Overflow in the [`Iterator`] implementation (when the contained
390/// data type reaches its numerical limit) is allowed to panic, wrap, or
391/// saturate. This behavior is defined by the implementation of the [`Step`]
392/// trait. For primitive integers, this follows the normal rules, and respects
393/// the overflow checks profile (panic in debug, wrap in release). Note also
394/// that overflow happens earlier than you might assume: the overflow happens
395/// in the call to `next` that yields the maximum value, as the range must be
396/// set to a state to yield the next value.
397///
398/// [`Step`]: crate::iter::Step
399///
400/// # Examples
401///
402/// The `start..` syntax is a `RangeFrom`:
403///
404/// ```
405/// #![feature(new_range_api)]
406/// use core::range::RangeFrom;
407///
408/// assert_eq!(RangeFrom::from(2..), core::range::RangeFrom { start: 2 });
409/// assert_eq!(2 + 3 + 4, RangeFrom::from(2..).into_iter().take(3).sum());
410/// ```
411#[lang = "RangeFromCopy"]
412#[derive(Clone, Copy, PartialEq, Eq, Hash)]
413#[unstable(feature = "new_range_api", issue = "125687")]
414pub struct RangeFrom<Idx> {
415 /// The lower bound of the range (inclusive).
416 #[unstable(feature = "new_range_api", issue = "125687")]
417 pub start: Idx,
418}
419
420#[unstable(feature = "new_range_api", issue = "125687")]
421impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
422 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
423 self.start.fmt(fmt)?;
424 write!(fmt, "..")?;
425 Ok(())
426 }
427}
428
429impl<Idx: Step> RangeFrom<Idx> {
430 /// Creates an iterator over the elements within this range.
431 ///
432 /// Shorthand for `.clone().into_iter()`
433 ///
434 /// # Examples
435 ///
436 /// ```
437 /// #![feature(new_range_api)]
438 /// use core::range::RangeFrom;
439 ///
440 /// let mut i = RangeFrom::from(3..).iter().map(|n| n*n);
441 /// assert_eq!(i.next(), Some(9));
442 /// assert_eq!(i.next(), Some(16));
443 /// assert_eq!(i.next(), Some(25));
444 /// ```
445 #[unstable(feature = "new_range_api", issue = "125687")]
446 #[inline]
447 pub fn iter(&self) -> IterRangeFrom<Idx> {
448 self.clone().into_iter()
449 }
450}
451
452impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
453 /// Returns `true` if `item` is contained in the range.
454 ///
455 /// # Examples
456 ///
457 /// ```
458 /// #![feature(new_range_api)]
459 /// use core::range::RangeFrom;
460 ///
461 /// assert!(!RangeFrom::from(3..).contains(&2));
462 /// assert!( RangeFrom::from(3..).contains(&3));
463 /// assert!( RangeFrom::from(3..).contains(&1_000_000_000));
464 ///
465 /// assert!( RangeFrom::from(0.0..).contains(&0.5));
466 /// assert!(!RangeFrom::from(0.0..).contains(&f32::NAN));
467 /// assert!(!RangeFrom::from(f32::NAN..).contains(&0.5));
468 /// ```
469 #[inline]
470 #[unstable(feature = "new_range_api", issue = "125687")]
471 pub fn contains<U>(&self, item: &U) -> bool
472 where
473 Idx: PartialOrd<U>,
474 U: ?Sized + PartialOrd<Idx>,
475 {
476 <Self as RangeBounds<Idx>>::contains(self, item)
477 }
478}
479
480#[unstable(feature = "new_range_api", issue = "125687")]
481impl<T> RangeBounds<T> for RangeFrom<T> {
482 fn start_bound(&self) -> Bound<&T> {
483 Included(&self.start)
484 }
485 fn end_bound(&self) -> Bound<&T> {
486 Unbounded
487 }
488}
489
490#[unstable(feature = "new_range_api", issue = "125687")]
491impl<T> RangeBounds<T> for RangeFrom<&T> {
492 fn start_bound(&self) -> Bound<&T> {
493 Included(self.start)
494 }
495 fn end_bound(&self) -> Bound<&T> {
496 Unbounded
497 }
498}
499
500// #[unstable(feature = "range_into_bounds", issue = "136903")]
501#[unstable(feature = "new_range_api", issue = "125687")]
502impl<T> IntoBounds<T> for RangeFrom<T> {
503 fn into_bounds(self) -> (Bound<T>, Bound<T>) {
504 (Included(self.start), Unbounded)
505 }
506}
507
508#[unstable(feature = "new_range_api", issue = "125687")]
509impl<T> From<RangeFrom<T>> for legacy::RangeFrom<T> {
510 #[inline]
511 fn from(value: RangeFrom<T>) -> Self {
512 Self { start: value.start }
513 }
514}
515#[unstable(feature = "new_range_api", issue = "125687")]
516impl<T> From<legacy::RangeFrom<T>> for RangeFrom<T> {
517 #[inline]
518 fn from(value: legacy::RangeFrom<T>) -> Self {
519 Self { start: value.start }
520 }
521}
522

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