153 lines
3.8 KiB
Rust
153 lines
3.8 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![unstable(feature = "collections_range",
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reason = "waiting for dust to settle on inclusive ranges",
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issue = "30877")]
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//! Range syntax.
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use core::ops::{RangeFull, Range, RangeTo, RangeFrom, RangeInclusive, RangeToInclusive};
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use Bound::{self, Excluded, Included, Unbounded};
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/// `RangeArgument` is implemented by Rust's built-in range types, produced
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/// by range syntax like `..`, `a..`, `..b` or `c..d`.
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pub trait RangeArgument<T: ?Sized> {
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/// Start index bound.
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///
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/// Returns the start value as a `Bound`.
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///
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/// # Examples
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///
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/// ```
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/// #![feature(alloc)]
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/// #![feature(collections_range)]
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///
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/// extern crate alloc;
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///
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/// # fn main() {
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/// use alloc::range::RangeArgument;
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/// use alloc::Bound::*;
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///
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/// assert_eq!((..10).start(), Unbounded);
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/// assert_eq!((3..10).start(), Included(&3));
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/// # }
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/// ```
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fn start(&self) -> Bound<&T>;
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/// End index bound.
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///
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/// Returns the end value as a `Bound`.
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///
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/// # Examples
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///
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/// ```
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/// #![feature(alloc)]
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/// #![feature(collections_range)]
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///
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/// extern crate alloc;
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///
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/// # fn main() {
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/// use alloc::range::RangeArgument;
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/// use alloc::Bound::*;
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///
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/// assert_eq!((3..).end(), Unbounded);
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/// assert_eq!((3..10).end(), Excluded(&10));
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/// # }
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/// ```
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fn end(&self) -> Bound<&T>;
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}
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// FIXME add inclusive ranges to RangeArgument
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impl<T: ?Sized> RangeArgument<T> for RangeFull {
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fn start(&self) -> Bound<&T> {
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Unbounded
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}
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fn end(&self) -> Bound<&T> {
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Unbounded
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}
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}
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impl<T> RangeArgument<T> for RangeFrom<T> {
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fn start(&self) -> Bound<&T> {
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Included(&self.start)
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}
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fn end(&self) -> Bound<&T> {
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Unbounded
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}
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}
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impl<T> RangeArgument<T> for RangeTo<T> {
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fn start(&self) -> Bound<&T> {
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Unbounded
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}
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fn end(&self) -> Bound<&T> {
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Excluded(&self.end)
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}
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}
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impl<T> RangeArgument<T> for Range<T> {
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fn start(&self) -> Bound<&T> {
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Included(&self.start)
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}
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fn end(&self) -> Bound<&T> {
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Excluded(&self.end)
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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<T> RangeArgument<T> for RangeInclusive<T> {
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fn start(&self) -> Bound<&T> {
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Included(&self.start)
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}
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fn end(&self) -> Bound<&T> {
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Included(&self.end)
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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<T> RangeArgument<T> for RangeToInclusive<T> {
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fn start(&self) -> Bound<&T> {
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Unbounded
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}
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fn end(&self) -> Bound<&T> {
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Included(&self.end)
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}
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}
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impl<T> RangeArgument<T> for (Bound<T>, Bound<T>) {
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fn start(&self) -> Bound<&T> {
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match *self {
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(Included(ref start), _) => Included(start),
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(Excluded(ref start), _) => Excluded(start),
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(Unbounded, _) => Unbounded,
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}
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}
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fn end(&self) -> Bound<&T> {
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match *self {
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(_, Included(ref end)) => Included(end),
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(_, Excluded(ref end)) => Excluded(end),
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(_, Unbounded) => Unbounded,
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}
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}
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}
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impl<'a, T: ?Sized + 'a> RangeArgument<T> for (Bound<&'a T>, Bound<&'a T>) {
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fn start(&self) -> Bound<&T> {
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self.0
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}
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fn end(&self) -> Bound<&T> {
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self.1
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}
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}
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