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Revised core::ops::range::* docs

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Part of #29365.
* Strenghtened summary/explanation split, making phrasings more parallel
* Added links throughout
* Fixed some example formatting & removed extraneous `fn main()`s (or hid
  then when needed because of `#![features]`.
* Emphasized note on `RangeFrom`'s `Iterator` implementation
* Added summary sentences to (unstable) `contains` methods
This commit is contained in:
lukaramu 2017-08-07 22:55:20 +02:00
parent 5414c85689
commit f1cc7d6c14
1 changed files with 118 additions and 93 deletions
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211
src/libcore/ops/range.rs
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@ -10,10 +10,10 @@
use fmt;
/// An unbounded range. Use `..` (two dots) for its shorthand.
/// An unbounded range (`..`).
///
/// Its primary use case is slicing index. It cannot serve as an iterator
/// because it doesn't have a starting point.
/// `RangeFull` is primarily used as a [slicing index], it's shorthand is `..`.
/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
///
/// # Examples
///
@ -23,8 +23,8 @@ use fmt;
/// assert_eq!((..), std::ops::RangeFull);
/// ```
///
/// It does not have an `IntoIterator` implementation, so you can't use it in a
/// `for` loop directly. This won't compile:
/// It does not have an [`IntoIterator`] implementation, so you can't use it in
/// a `for` loop directly. This won't compile:
///
/// ```compile_fail,E0277
/// for i in .. {
@ -32,7 +32,7 @@ use fmt;
/// }
/// ```
///
/// Used as a slicing index, `RangeFull` produces the full array as a slice.
/// Used as a [slicing index], `RangeFull` produces the full array as a slice.
///
/// ```
/// let arr = [0, 1, 2, 3];
@ -41,6 +41,10 @@ use fmt;
/// assert_eq!(arr[1.. ], [ 1,2,3]);
/// assert_eq!(arr[1..3], [ 1,2 ]);
/// ```
///
/// [`IntoIterator`]: ../iter/trait.Iterator.html
/// [`Iterator`]: ../iter/trait.IntoIterator.html
/// [slicing index]: ../slice/trait.SliceIndex.html
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct RangeFull;
@ -52,24 +56,23 @@ impl fmt::Debug for RangeFull {
}
}
/// A (half-open) range which is bounded at both ends: { x | start <= x < end }.
/// Use `start..end` (two dots) for its shorthand.
/// A (half-open) range bounded inclusively below and exclusively above
/// (`start..end`).
///
/// See the [`contains`](#method.contains) method for its characterization.
/// The `Range` `start..end` contains all values with `x >= start` and
/// `x < end`.
///
/// # Examples
///
/// ```
/// fn main() {
/// assert_eq!((3..5), std::ops::Range{ start: 3, end: 5 });
/// assert_eq!(3+4+5, (3..6).sum());
/// assert_eq!((3..5), std::ops::Range { start: 3, end: 5 });
/// assert_eq!(3 + 4 + 5, (3..6).sum());
///
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ .. ], [0,1,2,3]);
/// assert_eq!(arr[ ..3], [0,1,2 ]);
/// assert_eq!(arr[1.. ], [ 1,2,3]);
/// assert_eq!(arr[1..3], [ 1,2 ]); // Range
/// }
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ .. ], [0,1,2,3]);
/// assert_eq!(arr[ ..3], [0,1,2 ]);
/// assert_eq!(arr[1.. ], [ 1,2,3]);
/// assert_eq!(arr[1..3], [ 1,2 ]); // Range
/// ```
#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
#[stable(feature = "rust1", since = "1.0.0")]
@ -91,49 +94,51 @@ impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
impl<Idx: PartialOrd<Idx>> Range<Idx> {
/// Returns `true` if `item` is contained in the range.
///
/// # Examples
///
/// ```
/// #![feature(range_contains)]
/// fn main() {
/// assert!( ! (3..5).contains(2));
/// assert!( (3..5).contains(3));
/// assert!( (3..5).contains(4));
/// assert!( ! (3..5).contains(5));
///
/// assert!( ! (3..3).contains(3));
/// assert!( ! (3..2).contains(3));
/// }
/// # fn main() {
/// assert!(!(3..5).contains(2));
/// assert!( (3..5).contains(3));
/// assert!( (3..5).contains(4));
/// assert!(!(3..5).contains(5));
///
/// assert!(!(3..3).contains(3));
/// assert!(!(3..2).contains(3));
/// # }
/// ```
pub fn contains(&self, item: Idx) -> bool {
(self.start <= item) && (item < self.end)
}
}
/// A range which is only bounded below: { x | start <= x }.
/// Use `start..` for its shorthand.
/// A range only bounded inclusively below (`start..`).
///
/// See the [`contains`](#method.contains) method for its characterization.
/// The `RangeFrom` `start..` contains all values with `x >= start`.
///
/// Note: Currently, no overflow checking is done for the iterator
/// *Note*: Currently, no overflow checking is done for the [`Iterator`]
/// implementation; if you use an integer range and the integer overflows, it
/// might panic in debug mode or create an endless loop in release mode. This
/// overflow behavior might change in the future.
/// might panic in debug mode or create an endless loop in release mode. **This
/// overflow behavior might change in the future.**
///
/// # Examples
///
/// ```
/// fn main() {
/// assert_eq!((2..), std::ops::RangeFrom{ start: 2 });
/// assert_eq!(2+3+4, (2..).take(3).sum());
/// assert_eq!((2..), std::ops::RangeFrom { start: 2 });
/// assert_eq!(2 + 3 + 4, (2..).take(3).sum());
///
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ .. ], [0,1,2,3]);
/// assert_eq!(arr[ ..3], [0,1,2 ]);
/// assert_eq!(arr[1.. ], [ 1,2,3]); // RangeFrom
/// assert_eq!(arr[1..3], [ 1,2 ]);
/// }
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ .. ], [0,1,2,3]);
/// assert_eq!(arr[ ..3], [0,1,2 ]);
/// assert_eq!(arr[1.. ], [ 1,2,3]); // RangeFrom
/// assert_eq!(arr[1..3], [ 1,2 ]);
/// ```
///
/// [`Iterator`]: ../iter/trait.IntoIterator.html
#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
#[stable(feature = "rust1", since = "1.0.0")]
pub struct RangeFrom<Idx> {
@ -151,38 +156,39 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
/// Returns `true` if `item` is contained in the range.
///
/// # Examples
///
/// ```
/// #![feature(range_contains)]
/// fn main() {
/// assert!( ! (3..).contains(2));
/// assert!( (3..).contains(3));
/// assert!( (3..).contains(1_000_000_000));
/// }
///
/// # fn main() {
/// assert!(!(3..).contains(2));
/// assert!( (3..).contains(3));
/// assert!( (3..).contains(1_000_000_000));
/// # }
/// ```
pub fn contains(&self, item: Idx) -> bool {
(self.start <= item)
}
}
/// A range which is only bounded above: { x | x < end }.
/// Use `..end` (two dots) for its shorthand.
/// A range only bounded exclusively above (`..end`).
///
/// See the [`contains`](#method.contains) method for its characterization.
///
/// It cannot serve as an iterator because it doesn't have a starting point.
/// The `RangeTo` `..end` contains all values with `x < end`.
/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
///
/// # Examples
///
/// The `..{integer}` syntax is a `RangeTo`:
/// The `..end` syntax is a `RangeTo`:
///
/// ```
/// assert_eq!((..5), std::ops::RangeTo{ end: 5 });
/// assert_eq!((..5), std::ops::RangeTo { end: 5 });
/// ```
///
/// It does not have an `IntoIterator` implementation, so you can't use it in a
/// `for` loop directly. This won't compile:
/// It does not have an [`IntoIterator`] implementation, so you can't use it in
/// a `for` loop directly. This won't compile:
///
/// ```compile_fail,E0277
/// for i in ..5 {
@ -190,7 +196,7 @@ impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
/// }
/// ```
///
/// When used as a slicing index, `RangeTo` produces a slice of all array
/// When used as a [slicing index], `RangeTo` produces a slice of all array
/// elements before the index indicated by `end`.
///
/// ```
@ -200,6 +206,10 @@ impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
/// assert_eq!(arr[1.. ], [ 1,2,3]);
/// assert_eq!(arr[1..3], [ 1,2 ]);
/// ```
///
/// [`IntoIterator`]: ../iter/trait.Iterator.html
/// [`Iterator`]: ../iter/trait.IntoIterator.html
/// [slicing index]: ../slice/trait.SliceIndex.html
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct RangeTo<Idx> {
@ -217,38 +227,42 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
/// Returns `true` if `item` is contained in the range.
///
/// # Examples
///
/// ```
/// #![feature(range_contains)]
/// fn main() {
/// assert!( (..5).contains(-1_000_000_000));
/// assert!( (..5).contains(4));
/// assert!( ! (..5).contains(5));
/// }
///
/// # fn main() {
/// assert!( (..5).contains(-1_000_000_000));
/// assert!( (..5).contains(4));
/// assert!(!(..5).contains(5));
/// # }
/// ```
pub fn contains(&self, item: Idx) -> bool {
(item < self.end)
}
}
/// An inclusive range which is bounded at both ends: { x | start <= x <= end }.
/// Use `start...end` (three dots) for its shorthand.
/// An range bounded inclusively below and above (`start...end`).
///
/// See the [`contains`](#method.contains) method for its characterization.
/// The `RangeInclusive` `start...end` contains all values with `x >= start`
/// and `x <= end`.
///
/// # Examples
///
/// ```
/// #![feature(inclusive_range,inclusive_range_syntax)]
/// fn main() {
/// assert_eq!((3...5), std::ops::RangeInclusive{ start: 3, end: 5 });
/// assert_eq!(3+4+5, (3...5).sum());
///
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ ...2], [0,1,2 ]);
/// assert_eq!(arr[1...2], [ 1,2 ]); // RangeInclusive
/// }
/// # fn main() {
/// assert_eq!((3...5), std::ops::RangeInclusive { start: 3, end: 5 });
/// assert_eq!(3 + 4 + 5, (3...5).sum());
///
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ ...2], [0,1,2 ]);
/// assert_eq!(arr[1...2], [ 1,2 ]); // RangeInclusive
/// # }
/// ```
#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
@ -274,43 +288,44 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
/// Returns `true` if `item` is contained in the range.
///
/// # Examples
///
/// ```
/// #![feature(range_contains,inclusive_range_syntax)]
/// fn main() {
/// assert!( ! (3...5).contains(2));
/// assert!( (3...5).contains(3));
/// assert!( (3...5).contains(4));
/// assert!( (3...5).contains(5));
/// assert!( ! (3...5).contains(6));
///
/// assert!( (3...3).contains(3));
/// assert!( ! (3...2).contains(3));
/// }
/// # fn main() {
/// assert!(!(3...5).contains(2));
/// assert!( (3...5).contains(3));
/// assert!( (3...5).contains(4));
/// assert!( (3...5).contains(5));
/// assert!(!(3...5).contains(6));
///
/// assert!( (3...3).contains(3));
/// assert!(!(3...2).contains(3));
/// # }
/// ```
pub fn contains(&self, item: Idx) -> bool {
self.start <= item && item <= self.end
}
}
/// An inclusive range which is only bounded above: { x | x <= end }.
/// Use `...end` (three dots) for its shorthand.
/// A range only bounded inclusively above (`...end`).
///
/// See the [`contains`](#method.contains) method for its characterization.
///
/// It cannot serve as an iterator because it doesn't have a starting point.
/// The `RangeToInclusive` `...end` contains all values with `x <= end`.
/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
///
/// # Examples
///
/// The `...{integer}` syntax is a `RangeToInclusive`:
/// The `...end` syntax is a `RangeToInclusive`:
///
/// ```
/// #![feature(inclusive_range,inclusive_range_syntax)]
/// assert_eq!((...5), std::ops::RangeToInclusive{ end: 5 });
/// ```
///
/// It does not have an `IntoIterator` implementation, so you can't use it in a
/// It does not have an [`IntoIterator`] implementation, so you can't use it in a
/// `for` loop directly. This won't compile:
///
/// ```compile_fail,E0277
@ -320,15 +335,22 @@ impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
/// }
/// ```
///
/// When used as a slicing index, `RangeToInclusive` produces a slice of all
/// When used as a [slicing index], `RangeToInclusive` produces a slice of all
/// array elements up to and including the index indicated by `end`.
///
/// ```
/// #![feature(inclusive_range_syntax)]
///
/// # fn main() {
/// let arr = [0, 1, 2, 3];
/// assert_eq!(arr[ ...2], [0,1,2 ]); // RangeToInclusive
/// assert_eq!(arr[1...2], [ 1,2 ]);
/// # }
/// ```
///
/// [`IntoIterator`]: ../iter/trait.Iterator.html
/// [`Iterator`]: ../iter/trait.IntoIterator.html
/// [slicing index]: ../slice/trait.SliceIndex.html
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
pub struct RangeToInclusive<Idx> {
@ -348,15 +370,18 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> {
/// Returns `true` if `item` is contained in the range.
///
/// # Examples
///
/// ```
/// #![feature(range_contains,inclusive_range_syntax)]
/// fn main() {
/// assert!( (...5).contains(-1_000_000_000));
/// assert!( (...5).contains(5));
/// assert!( ! (...5).contains(6));
/// }
///
/// # fn main() {
/// assert!( (...5).contains(-1_000_000_000));
/// assert!( (...5).contains(5));
/// assert!(!(...5).contains(6));
/// # }
/// ```
pub fn contains(&self, item: Idx) -> bool {
(item <= self.end)