core: add inclusive ranges to core::ops
Since it removes the old iter::{range_inclusive, RangeInclusive} which
were unstable and deprecated, this is a [breaking-change] on nightly.
This commit is contained in:
Alex Burka
parent
f1e191c0b9
commit
c5d58de665
3 changed files with 167 additions and 91 deletions
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@ -4375,95 +4375,6 @@ impl<A> Iterator for StepBy<A, RangeFrom<A>> where
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}
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}
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/// An iterator over the range [start, stop]
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#[derive(Clone)]
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#[unstable(feature = "range_inclusive",
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reason = "likely to be replaced by range notation and adapters",
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issue = "27777")]
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#[rustc_deprecated(since = "1.5.0", reason = "replaced with ... syntax")]
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#[allow(deprecated)]
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pub struct RangeInclusive<A> {
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range: ops::Range<A>,
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done: bool,
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}
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/// Returns an iterator over the range [start, stop].
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#[inline]
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#[unstable(feature = "range_inclusive",
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reason = "likely to be replaced by range notation and adapters",
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issue = "27777")]
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#[rustc_deprecated(since = "1.5.0", reason = "replaced with ... syntax")]
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#[allow(deprecated)]
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pub fn range_inclusive<A>(start: A, stop: A) -> RangeInclusive<A>
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where A: Step + One + Clone
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{
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RangeInclusive {
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range: start..stop,
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done: false,
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}
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}
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#[unstable(feature = "range_inclusive",
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reason = "likely to be replaced by range notation and adapters",
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issue = "27777")]
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#[rustc_deprecated(since = "1.5.0", reason = "replaced with ... syntax")]
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#[allow(deprecated)]
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impl<A> Iterator for RangeInclusive<A> where
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A: PartialEq + Step + One + Clone,
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for<'a> &'a A: Add<&'a A, Output = A>
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{
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type Item = A;
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#[inline]
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fn next(&mut self) -> Option<A> {
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self.range.next().or_else(|| {
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if !self.done && self.range.start == self.range.end {
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self.done = true;
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Some(self.range.end.clone())
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} else {
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None
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}
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})
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}
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#[inline]
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fn size_hint(&self) -> (usize, Option<usize>) {
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let (lo, hi) = self.range.size_hint();
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if self.done {
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(lo, hi)
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} else {
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let lo = lo.saturating_add(1);
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let hi = hi.and_then(|x| x.checked_add(1));
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(lo, hi)
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}
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}
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}
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#[unstable(feature = "range_inclusive",
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reason = "likely to be replaced by range notation and adapters",
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issue = "27777")]
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#[rustc_deprecated(since = "1.5.0", reason = "replaced with ... syntax")]
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#[allow(deprecated)]
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impl<A> DoubleEndedIterator for RangeInclusive<A> where
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A: PartialEq + Step + One + Clone,
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for<'a> &'a A: Add<&'a A, Output = A>,
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for<'a> &'a A: Sub<Output=A>
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{
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#[inline]
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fn next_back(&mut self) -> Option<A> {
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if self.range.end > self.range.start {
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let result = self.range.end.clone();
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self.range.end = &self.range.end - &A::one();
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Some(result)
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} else if !self.done && self.range.start == self.range.end {
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self.done = true;
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Some(self.range.end.clone())
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} else {
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None
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}
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<A: Step + Zero + Clone> Iterator for StepBy<A, ops::Range<A>> {
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type Item = A;
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@ -4505,6 +4416,9 @@ macro_rules! range_exact_iter_impl {
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($($t:ty)*) => ($(
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#[stable(feature = "rust1", since = "1.0.0")]
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impl ExactSizeIterator for ops::Range<$t> { }
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl ExactSizeIterator for ops::RangeInclusive<$t> { }
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)*)
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}
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@ -4568,6 +4482,99 @@ impl<A: Step + One> Iterator for ops::RangeFrom<A> where
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}
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}
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl<A: Step + One> Iterator for ops::RangeInclusive<A> where
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for<'a> &'a A: Add<&'a A, Output = A>
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{
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type Item = A;
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#[inline]
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fn next(&mut self) -> Option<A> {
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use ops::RangeInclusive::*;
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// this function has a sort of odd structure due to borrowck issues
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// we may need to replace self, so borrows of self.start and self.end need to end early
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let (finishing, n) = match *self {
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Empty { .. } => (None, None), // empty iterators yield no values
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NonEmpty { ref mut start, ref mut end } => {
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let one = A::one();
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if start <= end {
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let mut n = &*start + &one;
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mem::swap(&mut n, start);
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// if the iterator is done iterating, it will change from NonEmpty to Empty
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// to avoid unnecessary drops or clones, we'll reuse either start or end
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// (they are equal now, so it doesn't matter which)
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// to pull out end, we need to swap something back in -- use the previously
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// created A::one() as a dummy value
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(if n == *end { Some(mem::replace(end, one)) } else { None },
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// ^ are we done yet?
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Some(n)) // < the value to output
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} else {
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(Some(mem::replace(start, one)), None)
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}
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}
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};
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// turn into an empty iterator if this is the last value
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if let Some(end) = finishing {
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*self = Empty { at: end };
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}
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n
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}
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#[inline]
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fn size_hint(&self) -> (usize, Option<usize>) {
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use ops::RangeInclusive::*;
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match *self {
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Empty { .. } => (0, Some(0)),
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NonEmpty { ref start, ref end } =>
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match Step::steps_between(start, end, &A::one()) {
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Some(hint) => (hint.saturating_add(1), hint.checked_add(1)),
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None => (0, None),
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}
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}
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}
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}
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl<A: Step + One> DoubleEndedIterator for ops::RangeInclusive<A> where
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for<'a> &'a A: Add<&'a A, Output = A>,
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for<'a> &'a A: Sub<&'a A, Output = A>
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{
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#[inline]
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fn next_back(&mut self) -> Option<A> {
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use ops::RangeInclusive::*;
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// see Iterator::next for comments
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let (finishing, n) = match *self {
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Empty { .. } => return None,
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NonEmpty { ref mut start, ref mut end } => {
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let one = A::one();
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let mut n = &*end - &one;
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mem::swap(&mut n, end);
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(if n == *start { Some(mem::replace(start, one)) } else { None },
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n)
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}
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};
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if let Some(start) = finishing {
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*self = Empty { at: start };
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}
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Some(n)
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}
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}
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/// An iterator that repeats an element endlessly.
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///
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/// This `struct` is created by the [`repeat()`] function. See its documentation for more.
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@ -67,8 +67,11 @@
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#![stable(feature = "rust1", since = "1.0.0")]
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use marker::{Sized, Unsize};
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use cmp::PartialOrd;
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use fmt;
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use convert::From;
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use marker::{Sized, Unsize};
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use num::One;
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/// The `Drop` trait is used to run some code when a value goes out of scope.
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/// This is sometimes called a 'destructor'.
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@ -1530,6 +1533,73 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
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}
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}
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/// An inclusive range which is bounded at both ends.
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#[derive(Copy, Clone, PartialEq, Eq)]
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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pub enum RangeInclusive<Idx> {
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/// Empty range (iteration has finished)
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Empty {
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/// The point at which iteration finished
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at: Idx
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},
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/// Non-empty range (iteration will yield value(s))
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NonEmpty {
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/// The lower bound of the range (inclusive).
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start: Idx,
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/// The upper bound of the range (inclusive).
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end: Idx,
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},
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}
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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use self::RangeInclusive::*;
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match *self {
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Empty { ref at } => write!(fmt, "[empty range @ {:?}]", at),
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NonEmpty { ref start, ref end } => write!(fmt, "{:?}...{:?}", start, end),
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}
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}
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}
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl<Idx: PartialOrd + One + Sub<Output=Idx>> From<Range<Idx>> for RangeInclusive<Idx> {
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fn from(range: Range<Idx>) -> RangeInclusive<Idx> {
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use self::RangeInclusive::*;
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if range.start < range.end {
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NonEmpty {
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start: range.start,
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end: range.end - Idx::one() // can't underflow because end > start >= MIN
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}
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} else {
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Empty {
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at: range.start
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}
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}
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}
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}
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/// An inclusive range which is only bounded above.
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#[derive(Copy, Clone, PartialEq, Eq)]
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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pub struct RangeToInclusive<Idx> {
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/// The upper bound of the range (inclusive)
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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pub end: Idx,
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}
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#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
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impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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write!(fmt, "...{:?}", self.end)
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}
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}
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// RangeToInclusive<Idx> cannot impl From<RangeTo<Idx>>
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// because underflow would be possible with (..0).into()
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/// The `Deref` trait is used to specify the functionality of dereferencing
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/// operations, like `*v`.
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///
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@ -247,7 +247,6 @@
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#![feature(optin_builtin_traits)]
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#![feature(placement_in_syntax)]
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#![feature(rand)]
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#![feature(range_inclusive)]
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#![feature(raw)]
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#![feature(repr_simd)]
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#![feature(reflect_marker)]
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