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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Overloadable operators. //! //! Implementing these traits allows you to overload certain operators. //! //! Some of these traits are imported by the prelude, so they are available in //! every Rust program. Only operators backed by traits can be overloaded. For //! example, the addition operator (`+`) can be overloaded through the [`Add`] //! trait, but since the assignment operator (`=`) has no backing trait, there //! is no way of overloading its semantics. Additionally, this module does not //! provide any mechanism to create new operators. If traitless overloading or //! custom operators are required, you should look toward macros or compiler //! plugins to extend Rust's syntax. //! //! Note that the `&&` and `||` operators short-circuit, i.e. they only //! evaluate their second operand if it contributes to the result. Since this //! behavior is not enforceable by traits, `&&` and `||` are not supported as //! overloadable operators. //! //! Many of the operators take their operands by value. In non-generic //! contexts involving built-in types, this is usually not a problem. //! However, using these operators in generic code, requires some //! attention if values have to be reused as opposed to letting the operators //! consume them. One option is to occasionally use [`clone`]. //! Another option is to rely on the types involved providing additional //! operator implementations for references. For example, for a user-defined //! type `T` which is supposed to support addition, it is probably a good //! idea to have both `T` and `&T` implement the traits [`Add<T>`][`Add`] and //! [`Add<&T>`][`Add`] so that generic code can be written without unnecessary //! cloning. //! //! # Examples //! //! This example creates a `Point` struct that implements [`Add`] and [`Sub`], //! and then demonstrates adding and subtracting two `Point`s. //! //! ```rust //! use std::ops::{Add, Sub}; //! //! #[derive(Debug)] //! struct Point { //! x: i32, //! y: i32, //! } //! //! impl Add for Point { //! type Output = Point; //! //! fn add(self, other: Point) -> Point { //! Point {x: self.x + other.x, y: self.y + other.y} //! } //! } //! //! impl Sub for Point { //! type Output = Point; //! //! fn sub(self, other: Point) -> Point { //! Point {x: self.x - other.x, y: self.y - other.y} //! } //! } //! fn main() { //! println!("{:?}", Point {x: 1, y: 0} + Point {x: 2, y: 3}); //! println!("{:?}", Point {x: 1, y: 0} - Point {x: 2, y: 3}); //! } //! ``` //! //! See the documentation for each trait for an example implementation. //! //! The [`Fn`], [`FnMut`], and [`FnOnce`] traits are implemented by types that can be //! invoked like functions. Note that [`Fn`] takes `&self`, [`FnMut`] takes `&mut //! self` and [`FnOnce`] takes `self`. These correspond to the three kinds of //! methods that can be invoked on an instance: call-by-reference, //! call-by-mutable-reference, and call-by-value. The most common use of these //! traits is to act as bounds to higher-level functions that take functions or //! closures as arguments. //! //! Taking a [`Fn`] as a parameter: //! //! ```rust //! fn call_with_one<F>(func: F) -> usize //! where F: Fn(usize) -> usize //! { //! func(1) //! } //! //! let double = |x| x * 2; //! assert_eq!(call_with_one(double), 2); //! ``` //! //! Taking a [`FnMut`] as a parameter: //! //! ```rust //! fn do_twice<F>(mut func: F) //! where F: FnMut() //! { //! func(); //! func(); //! } //! //! let mut x: usize = 1; //! { //! let add_two_to_x = || x += 2; //! do_twice(add_two_to_x); //! } //! //! assert_eq!(x, 5); //! ``` //! //! Taking a [`FnOnce`] as a parameter: //! //! ```rust //! fn consume_with_relish<F>(func: F) //! where F: FnOnce() -> String //! { //! // `func` consumes its captured variables, so it cannot be run more //! // than once //! println!("Consumed: {}", func()); //! //! println!("Delicious!"); //! //! // Attempting to invoke `func()` again will throw a `use of moved //! // value` error for `func` //! } //! //! let x = String::from("x"); //! let consume_and_return_x = move || x; //! consume_with_relish(consume_and_return_x); //! //! // `consume_and_return_x` can no longer be invoked at this point //! ``` //! //! [`Fn`]: trait.Fn.html //! [`FnMut`]: trait.FnMut.html //! [`FnOnce`]: trait.FnOnce.html //! [`Add`]: trait.Add.html //! [`Sub`]: trait.Sub.html //! [`clone`]: ../clone/trait.Clone.html#tymethod.clone #![stable(feature = "rust1", since = "1.0.0")] use fmt; use marker::Unsize; /// The `Drop` trait is used to run some code when a value goes out of scope. /// This is sometimes called a 'destructor'. /// /// When a value goes out of scope, if it implements this trait, it will have /// its `drop` method called. Then any fields the value contains will also /// be dropped recursively. /// /// Because of the recursive dropping, you do not need to implement this trait /// unless your type needs its own destructor logic. /// /// # Examples /// /// A trivial implementation of `Drop`. The `drop` method is called when `_x` /// goes out of scope, and therefore `main` prints `Dropping!`. /// /// ``` /// struct HasDrop; /// /// impl Drop for HasDrop { /// fn drop(&mut self) { /// println!("Dropping!"); /// } /// } /// /// fn main() { /// let _x = HasDrop; /// } /// ``` /// /// Showing the recursive nature of `Drop`. When `outer` goes out of scope, the /// `drop` method will be called first for `Outer`, then for `Inner`. Therefore /// `main` prints `Dropping Outer!` and then `Dropping Inner!`. /// /// ``` /// struct Inner; /// struct Outer(Inner); /// /// impl Drop for Inner { /// fn drop(&mut self) { /// println!("Dropping Inner!"); /// } /// } /// /// impl Drop for Outer { /// fn drop(&mut self) { /// println!("Dropping Outer!"); /// } /// } /// /// fn main() { /// let _x = Outer(Inner); /// } /// ``` /// /// Because variables are dropped in the reverse order they are declared, /// `main` will print `Declared second!` and then `Declared first!`. /// /// ``` /// struct PrintOnDrop(&'static str); /// /// fn main() { /// let _first = PrintOnDrop("Declared first!"); /// let _second = PrintOnDrop("Declared second!"); /// } /// ``` #[lang = "drop"] #[stable(feature = "rust1", since = "1.0.0")] pub trait Drop { /// A method called when the value goes out of scope. /// /// When this method has been called, `self` has not yet been deallocated. /// If it were, `self` would be a dangling reference. /// /// After this function is over, the memory of `self` will be deallocated. /// /// This function cannot be called explicitly. This is compiler error /// [E0040]. However, the [`std::mem::drop`] function in the prelude can be /// used to call the argument's `Drop` implementation. /// /// [E0040]: ../../error-index.html#E0040 /// [`std::mem::drop`]: ../../std/mem/fn.drop.html /// /// # Panics /// /// Given that a `panic!` will call `drop()` as it unwinds, any `panic!` in /// a `drop()` implementation will likely abort. #[stable(feature = "rust1", since = "1.0.0")] fn drop(&mut self); } /// The addition operator `+`. /// /// # Examples /// /// This example creates a `Point` struct that implements the `Add` trait, and /// then demonstrates adding two `Point`s. /// /// ``` /// use std::ops::Add; /// /// #[derive(Debug)] /// struct Point { /// x: i32, /// y: i32, /// } /// /// impl Add for Point { /// type Output = Point; /// /// fn add(self, other: Point) -> Point { /// Point { /// x: self.x + other.x, /// y: self.y + other.y, /// } /// } /// } /// /// impl PartialEq for Point { /// fn eq(&self, other: &Self) -> bool { /// self.x == other.x && self.y == other.y /// } /// } /// /// fn main() { /// assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 }, /// Point { x: 3, y: 3 }); /// } /// ``` /// /// Here is an example of the same `Point` struct implementing the `Add` trait /// using generics. /// /// ``` /// use std::ops::Add; /// /// #[derive(Debug)] /// struct Point<T> { /// x: T, /// y: T, /// } /// /// // Notice that the implementation uses the `Output` associated type /// impl<T: Add<Output=T>> Add for Point<T> { /// type Output = Point<T>; /// /// fn add(self, other: Point<T>) -> Point<T> { /// Point { /// x: self.x + other.x, /// y: self.y + other.y, /// } /// } /// } /// /// impl<T: PartialEq> PartialEq for Point<T> { /// fn eq(&self, other: &Self) -> bool { /// self.x == other.x && self.y == other.y /// } /// } /// /// fn main() { /// assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 }, /// Point { x: 3, y: 3 }); /// } /// ``` /// /// Note that `RHS = Self` by default, but this is not mandatory. For example, /// [std::time::SystemTime] implements `Add<Duration>`, which permits /// operations of the form `SystemTime = SystemTime + Duration`. /// /// [std::time::SystemTime]: ../../std/time/struct.SystemTime.html #[lang = "add"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} + {RHS}`"] pub trait Add<RHS=Self> { /// The resulting type after applying the `+` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `+` operator #[stable(feature = "rust1", since = "1.0.0")] fn add(self, rhs: RHS) -> Self::Output; } macro_rules! add_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Add for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn add(self, other: $t) -> $t { self + other } } forward_ref_binop! { impl Add, add for $t, $t } )*) } add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The subtraction operator `-`. /// /// # Examples /// /// This example creates a `Point` struct that implements the `Sub` trait, and /// then demonstrates subtracting two `Point`s. /// /// ``` /// use std::ops::Sub; /// /// #[derive(Debug)] /// struct Point { /// x: i32, /// y: i32, /// } /// /// impl Sub for Point { /// type Output = Point; /// /// fn sub(self, other: Point) -> Point { /// Point { /// x: self.x - other.x, /// y: self.y - other.y, /// } /// } /// } /// /// impl PartialEq for Point { /// fn eq(&self, other: &Self) -> bool { /// self.x == other.x && self.y == other.y /// } /// } /// /// fn main() { /// assert_eq!(Point { x: 3, y: 3 } - Point { x: 2, y: 3 }, /// Point { x: 1, y: 0 }); /// } /// ``` /// /// Note that `RHS = Self` by default, but this is not mandatory. For example, /// [std::time::SystemTime] implements `Sub<Duration>`, which permits /// operations of the form `SystemTime = SystemTime - Duration`. /// /// [std::time::SystemTime]: ../../std/time/struct.SystemTime.html #[lang = "sub"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} - {RHS}`"] pub trait Sub<RHS=Self> { /// The resulting type after applying the `-` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `-` operator #[stable(feature = "rust1", since = "1.0.0")] fn sub(self, rhs: RHS) -> Self::Output; } macro_rules! sub_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Sub for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn sub(self, other: $t) -> $t { self - other } } forward_ref_binop! { impl Sub, sub for $t, $t } )*) } sub_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The multiplication operator `*`. /// /// # Examples /// /// Implementing a `Mul`tipliable rational number struct: /// /// ``` /// use std::ops::Mul; /// /// // The uniqueness of rational numbers in lowest terms is a consequence of /// // the fundamental theorem of arithmetic. /// #[derive(Eq)] /// #[derive(PartialEq, Debug)] /// struct Rational { /// nominator: usize, /// denominator: usize, /// } /// /// impl Rational { /// fn new(nominator: usize, denominator: usize) -> Self { /// if denominator == 0 { /// panic!("Zero is an invalid denominator!"); /// } /// /// // Reduce to lowest terms by dividing by the greatest common /// // divisor. /// let gcd = gcd(nominator, denominator); /// Rational { /// nominator: nominator / gcd, /// denominator: denominator / gcd, /// } /// } /// } /// /// impl Mul for Rational { /// // The multiplication of rational numbers is a closed operation. /// type Output = Self; /// /// fn mul(self, rhs: Self) -> Self { /// let nominator = self.nominator * rhs.nominator; /// let denominator = self.denominator * rhs.denominator; /// Rational::new(nominator, denominator) /// } /// } /// /// // Euclid's two-thousand-year-old algorithm for finding the greatest common /// // divisor. /// fn gcd(x: usize, y: usize) -> usize { /// let mut x = x; /// let mut y = y; /// while y != 0 { /// let t = y; /// y = x % y; /// x = t; /// } /// x /// } /// /// assert_eq!(Rational::new(1, 2), Rational::new(2, 4)); /// assert_eq!(Rational::new(2, 3) * Rational::new(3, 4), /// Rational::new(1, 2)); /// ``` /// /// Note that `RHS = Self` by default, but this is not mandatory. Here is an /// implementation which enables multiplication of vectors by scalars, as is /// done in linear algebra. /// /// ``` /// use std::ops::Mul; /// /// struct Scalar {value: usize}; /// /// #[derive(Debug)] /// struct Vector {value: Vec<usize>}; /// /// impl Mul<Vector> for Scalar { /// type Output = Vector; /// /// fn mul(self, rhs: Vector) -> Vector { /// Vector {value: rhs.value.iter().map(|v| self.value * v).collect()} /// } /// } /// /// impl PartialEq<Vector> for Vector { /// fn eq(&self, other: &Self) -> bool { /// self.value == other.value /// } /// } /// /// let scalar = Scalar{value: 3}; /// let vector = Vector{value: vec![2, 4, 6]}; /// assert_eq!(scalar * vector, Vector{value: vec![6, 12, 18]}); /// ``` #[lang = "mul"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} * {RHS}`"] pub trait Mul<RHS=Self> { /// The resulting type after applying the `*` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `*` operator #[stable(feature = "rust1", since = "1.0.0")] fn mul(self, rhs: RHS) -> Self::Output; } macro_rules! mul_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Mul for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn mul(self, other: $t) -> $t { self * other } } forward_ref_binop! { impl Mul, mul for $t, $t } )*) } mul_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The division operator `/`. /// /// # Examples /// /// Implementing a `Div`idable rational number struct: /// /// ``` /// use std::ops::Div; /// /// // The uniqueness of rational numbers in lowest terms is a consequence of /// // the fundamental theorem of arithmetic. /// #[derive(Eq)] /// #[derive(PartialEq, Debug)] /// struct Rational { /// nominator: usize, /// denominator: usize, /// } /// /// impl Rational { /// fn new(nominator: usize, denominator: usize) -> Self { /// if denominator == 0 { /// panic!("Zero is an invalid denominator!"); /// } /// /// // Reduce to lowest terms by dividing by the greatest common /// // divisor. /// let gcd = gcd(nominator, denominator); /// Rational { /// nominator: nominator / gcd, /// denominator: denominator / gcd, /// } /// } /// } /// /// impl Div for Rational { /// // The division of rational numbers is a closed operation. /// type Output = Self; /// /// fn div(self, rhs: Self) -> Self { /// if rhs.nominator == 0 { /// panic!("Cannot divide by zero-valued `Rational`!"); /// } /// /// let nominator = self.nominator * rhs.denominator; /// let denominator = self.denominator * rhs.nominator; /// Rational::new(nominator, denominator) /// } /// } /// /// // Euclid's two-thousand-year-old algorithm for finding the greatest common /// // divisor. /// fn gcd(x: usize, y: usize) -> usize { /// let mut x = x; /// let mut y = y; /// while y != 0 { /// let t = y; /// y = x % y; /// x = t; /// } /// x /// } /// /// fn main() { /// assert_eq!(Rational::new(1, 2), Rational::new(2, 4)); /// assert_eq!(Rational::new(1, 2) / Rational::new(3, 4), /// Rational::new(2, 3)); /// } /// ``` /// /// Note that `RHS = Self` by default, but this is not mandatory. Here is an /// implementation which enables division of vectors by scalars, as is done in /// linear algebra. /// /// ``` /// use std::ops::Div; /// /// struct Scalar {value: f32}; /// /// #[derive(Debug)] /// struct Vector {value: Vec<f32>}; /// /// impl Div<Scalar> for Vector { /// type Output = Vector; /// /// fn div(self, rhs: Scalar) -> Vector { /// Vector {value: self.value.iter().map(|v| v / rhs.value).collect()} /// } /// } /// /// impl PartialEq<Vector> for Vector { /// fn eq(&self, other: &Self) -> bool { /// self.value == other.value /// } /// } /// /// let scalar = Scalar{value: 2f32}; /// let vector = Vector{value: vec![2f32, 4f32, 6f32]}; /// assert_eq!(vector / scalar, Vector{value: vec![1f32, 2f32, 3f32]}); /// ``` #[lang = "div"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} / {RHS}`"] pub trait Div<RHS=Self> { /// The resulting type after applying the `/` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `/` operator #[stable(feature = "rust1", since = "1.0.0")] fn div(self, rhs: RHS) -> Self::Output; } macro_rules! div_impl_integer { ($($t:ty)*) => ($( /// This operation rounds towards zero, truncating any /// fractional part of the exact result. #[stable(feature = "rust1", since = "1.0.0")] impl Div for $t { type Output = $t; #[inline] fn div(self, other: $t) -> $t { self / other } } forward_ref_binop! { impl Div, div for $t, $t } )*) } div_impl_integer! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } macro_rules! div_impl_float { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Div for $t { type Output = $t; #[inline] fn div(self, other: $t) -> $t { self / other } } forward_ref_binop! { impl Div, div for $t, $t } )*) } div_impl_float! { f32 f64 } /// The remainder operator `%`. /// /// # Examples /// /// This example implements `Rem` on a `SplitSlice` object. After `Rem` is /// implemented, one can use the `%` operator to find out what the remaining /// elements of the slice would be after splitting it into equal slices of a /// given length. /// /// ``` /// use std::ops::Rem; /// /// #[derive(PartialEq, Debug)] /// struct SplitSlice<'a, T: 'a> { /// slice: &'a [T], /// } /// /// impl<'a, T> Rem<usize> for SplitSlice<'a, T> { /// type Output = SplitSlice<'a, T>; /// /// fn rem(self, modulus: usize) -> Self { /// let len = self.slice.len(); /// let rem = len % modulus; /// let start = len - rem; /// SplitSlice {slice: &self.slice[start..]} /// } /// } /// /// // If we were to divide &[0, 1, 2, 3, 4, 5, 6, 7] into slices of size 3, /// // the remainder would be &[6, 7] /// assert_eq!(SplitSlice { slice: &[0, 1, 2, 3, 4, 5, 6, 7] } % 3, /// SplitSlice { slice: &[6, 7] }); /// ``` #[lang = "rem"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} % {RHS}`"] pub trait Rem<RHS=Self> { /// The resulting type after applying the `%` operator #[stable(feature = "rust1", since = "1.0.0")] type Output = Self; /// The method for the `%` operator #[stable(feature = "rust1", since = "1.0.0")] fn rem(self, rhs: RHS) -> Self::Output; } macro_rules! rem_impl_integer { ($($t:ty)*) => ($( /// This operation satisfies `n % d == n - (n / d) * d`. The /// result has the same sign as the left operand. #[stable(feature = "rust1", since = "1.0.0")] impl Rem for $t { type Output = $t; #[inline] fn rem(self, other: $t) -> $t { self % other } } forward_ref_binop! { impl Rem, rem for $t, $t } )*) } rem_impl_integer! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } macro_rules! rem_impl_float { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Rem for $t { type Output = $t; #[inline] fn rem(self, other: $t) -> $t { self % other } } forward_ref_binop! { impl Rem, rem for $t, $t } )*) } rem_impl_float! { f32 f64 } /// The unary negation operator `-`. /// /// # Examples /// /// An implementation of `Neg` for `Sign`, which allows the use of `-` to /// negate its value. /// /// ``` /// use std::ops::Neg; /// /// #[derive(Debug, PartialEq)] /// enum Sign { /// Negative, /// Zero, /// Positive, /// } /// /// impl Neg for Sign { /// type Output = Sign; /// /// fn neg(self) -> Sign { /// match self { /// Sign::Negative => Sign::Positive, /// Sign::Zero => Sign::Zero, /// Sign::Positive => Sign::Negative, /// } /// } /// } /// /// // a negative positive is a negative /// assert_eq!(-Sign::Positive, Sign::Negative); /// // a double negative is a positive /// assert_eq!(-Sign::Negative, Sign::Positive); /// // zero is its own negation /// assert_eq!(-Sign::Zero, Sign::Zero); /// ``` #[lang = "neg"] #[stable(feature = "rust1", since = "1.0.0")] pub trait Neg { /// The resulting type after applying the `-` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the unary `-` operator #[stable(feature = "rust1", since = "1.0.0")] fn neg(self) -> Self::Output; } macro_rules! neg_impl_core { ($id:ident => $body:expr, $($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Neg for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn neg(self) -> $t { let $id = self; $body } } forward_ref_unop! { impl Neg, neg for $t } )*) } macro_rules! neg_impl_numeric { ($($t:ty)*) => { neg_impl_core!{ x => -x, $($t)*} } } #[allow(unused_macros)] macro_rules! neg_impl_unsigned { ($($t:ty)*) => { neg_impl_core!{ x => { !x.wrapping_add(1) }, $($t)*} } } // neg_impl_unsigned! { usize u8 u16 u32 u64 } neg_impl_numeric! { isize i8 i16 i32 i64 i128 f32 f64 } /// The unary logical negation operator `!`. /// /// # Examples /// /// An implementation of `Not` for `Answer`, which enables the use of `!` to /// invert its value. /// /// ``` /// use std::ops::Not; /// /// #[derive(Debug, PartialEq)] /// enum Answer { /// Yes, /// No, /// } /// /// impl Not for Answer { /// type Output = Answer; /// /// fn not(self) -> Answer { /// match self { /// Answer::Yes => Answer::No, /// Answer::No => Answer::Yes /// } /// } /// } /// /// assert_eq!(!Answer::Yes, Answer::No); /// assert_eq!(!Answer::No, Answer::Yes); /// ``` #[lang = "not"] #[stable(feature = "rust1", since = "1.0.0")] pub trait Not { /// The resulting type after applying the `!` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the unary `!` operator #[stable(feature = "rust1", since = "1.0.0")] fn not(self) -> Self::Output; } macro_rules! not_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl Not for $t { type Output = $t; #[inline] fn not(self) -> $t { !self } } forward_ref_unop! { impl Not, not for $t } )*) } not_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The bitwise AND operator `&`. /// /// # Examples /// /// In this example, the `&` operator is lifted to a trivial `Scalar` type. /// /// ``` /// use std::ops::BitAnd; /// /// #[derive(Debug, PartialEq)] /// struct Scalar(bool); /// /// impl BitAnd for Scalar { /// type Output = Self; /// /// // rhs is the "right-hand side" of the expression `a & b` /// fn bitand(self, rhs: Self) -> Self { /// Scalar(self.0 & rhs.0) /// } /// } /// /// fn main() { /// assert_eq!(Scalar(true) & Scalar(true), Scalar(true)); /// assert_eq!(Scalar(true) & Scalar(false), Scalar(false)); /// assert_eq!(Scalar(false) & Scalar(true), Scalar(false)); /// assert_eq!(Scalar(false) & Scalar(false), Scalar(false)); /// } /// ``` /// /// In this example, the `BitAnd` trait is implemented for a `BooleanVector` /// struct. /// /// ``` /// use std::ops::BitAnd; /// /// #[derive(Debug, PartialEq)] /// struct BooleanVector(Vec<bool>); /// /// impl BitAnd for BooleanVector { /// type Output = Self; /// /// fn bitand(self, BooleanVector(rhs): Self) -> Self { /// let BooleanVector(lhs) = self; /// assert_eq!(lhs.len(), rhs.len()); /// BooleanVector(lhs.iter().zip(rhs.iter()).map(|(x, y)| *x && *y).collect()) /// } /// } /// /// fn main() { /// let bv1 = BooleanVector(vec![true, true, false, false]); /// let bv2 = BooleanVector(vec![true, false, true, false]); /// let expected = BooleanVector(vec![true, false, false, false]); /// assert_eq!(bv1 & bv2, expected); /// } /// ``` #[lang = "bitand"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} & {RHS}`"] pub trait BitAnd<RHS=Self> { /// The resulting type after applying the `&` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `&` operator #[stable(feature = "rust1", since = "1.0.0")] fn bitand(self, rhs: RHS) -> Self::Output; } macro_rules! bitand_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl BitAnd for $t { type Output = $t; #[inline] fn bitand(self, rhs: $t) -> $t { self & rhs } } forward_ref_binop! { impl BitAnd, bitand for $t, $t } )*) } bitand_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The bitwise OR operator `|`. /// /// # Examples /// /// In this example, the `|` operator is lifted to a trivial `Scalar` type. /// /// ``` /// use std::ops::BitOr; /// /// #[derive(Debug, PartialEq)] /// struct Scalar(bool); /// /// impl BitOr for Scalar { /// type Output = Self; /// /// // rhs is the "right-hand side" of the expression `a | b` /// fn bitor(self, rhs: Self) -> Self { /// Scalar(self.0 | rhs.0) /// } /// } /// /// fn main() { /// assert_eq!(Scalar(true) | Scalar(true), Scalar(true)); /// assert_eq!(Scalar(true) | Scalar(false), Scalar(true)); /// assert_eq!(Scalar(false) | Scalar(true), Scalar(true)); /// assert_eq!(Scalar(false) | Scalar(false), Scalar(false)); /// } /// ``` /// /// In this example, the `BitOr` trait is implemented for a `BooleanVector` /// struct. /// /// ``` /// use std::ops::BitOr; /// /// #[derive(Debug, PartialEq)] /// struct BooleanVector(Vec<bool>); /// /// impl BitOr for BooleanVector { /// type Output = Self; /// /// fn bitor(self, BooleanVector(rhs): Self) -> Self { /// let BooleanVector(lhs) = self; /// assert_eq!(lhs.len(), rhs.len()); /// BooleanVector(lhs.iter().zip(rhs.iter()).map(|(x, y)| *x || *y).collect()) /// } /// } /// /// fn main() { /// let bv1 = BooleanVector(vec![true, true, false, false]); /// let bv2 = BooleanVector(vec![true, false, true, false]); /// let expected = BooleanVector(vec![true, true, true, false]); /// assert_eq!(bv1 | bv2, expected); /// } /// ``` #[lang = "bitor"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} | {RHS}`"] pub trait BitOr<RHS=Self> { /// The resulting type after applying the `|` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `|` operator #[stable(feature = "rust1", since = "1.0.0")] fn bitor(self, rhs: RHS) -> Self::Output; } macro_rules! bitor_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl BitOr for $t { type Output = $t; #[inline] fn bitor(self, rhs: $t) -> $t { self | rhs } } forward_ref_binop! { impl BitOr, bitor for $t, $t } )*) } bitor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The bitwise XOR operator `^`. /// /// # Examples /// /// In this example, the `^` operator is lifted to a trivial `Scalar` type. /// /// ``` /// use std::ops::BitXor; /// /// #[derive(Debug, PartialEq)] /// struct Scalar(bool); /// /// impl BitXor for Scalar { /// type Output = Self; /// /// // rhs is the "right-hand side" of the expression `a ^ b` /// fn bitxor(self, rhs: Self) -> Self { /// Scalar(self.0 ^ rhs.0) /// } /// } /// /// fn main() { /// assert_eq!(Scalar(true) ^ Scalar(true), Scalar(false)); /// assert_eq!(Scalar(true) ^ Scalar(false), Scalar(true)); /// assert_eq!(Scalar(false) ^ Scalar(true), Scalar(true)); /// assert_eq!(Scalar(false) ^ Scalar(false), Scalar(false)); /// } /// ``` /// /// In this example, the `BitXor` trait is implemented for a `BooleanVector` /// struct. /// /// ``` /// use std::ops::BitXor; /// /// #[derive(Debug, PartialEq)] /// struct BooleanVector(Vec<bool>); /// /// impl BitXor for BooleanVector { /// type Output = Self; /// /// fn bitxor(self, BooleanVector(rhs): Self) -> Self { /// let BooleanVector(lhs) = self; /// assert_eq!(lhs.len(), rhs.len()); /// BooleanVector(lhs.iter() /// .zip(rhs.iter()) /// .map(|(x, y)| (*x || *y) && !(*x && *y)) /// .collect()) /// } /// } /// /// fn main() { /// let bv1 = BooleanVector(vec![true, true, false, false]); /// let bv2 = BooleanVector(vec![true, false, true, false]); /// let expected = BooleanVector(vec![false, true, true, false]); /// assert_eq!(bv1 ^ bv2, expected); /// } /// ``` #[lang = "bitxor"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} ^ {RHS}`"] pub trait BitXor<RHS=Self> { /// The resulting type after applying the `^` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `^` operator #[stable(feature = "rust1", since = "1.0.0")] fn bitxor(self, rhs: RHS) -> Self::Output; } macro_rules! bitxor_impl { ($($t:ty)*) => ($( #[stable(feature = "rust1", since = "1.0.0")] impl BitXor for $t { type Output = $t; #[inline] fn bitxor(self, other: $t) -> $t { self ^ other } } forward_ref_binop! { impl BitXor, bitxor for $t, $t } )*) } bitxor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The left shift operator `<<`. /// /// # Examples /// /// An implementation of `Shl` that lifts the `<<` operation on integers to a /// `Scalar` struct. /// /// ``` /// use std::ops::Shl; /// /// #[derive(PartialEq, Debug)] /// struct Scalar(usize); /// /// impl Shl<Scalar> for Scalar { /// type Output = Self; /// /// fn shl(self, Scalar(rhs): Self) -> Scalar { /// let Scalar(lhs) = self; /// Scalar(lhs << rhs) /// } /// } /// fn main() { /// assert_eq!(Scalar(4) << Scalar(2), Scalar(16)); /// } /// ``` /// /// An implementation of `Shl` that spins a vector leftward by a given amount. /// /// ``` /// use std::ops::Shl; /// /// #[derive(PartialEq, Debug)] /// struct SpinVector<T: Clone> { /// vec: Vec<T>, /// } /// /// impl<T: Clone> Shl<usize> for SpinVector<T> { /// type Output = Self; /// /// fn shl(self, rhs: usize) -> SpinVector<T> { /// // rotate the vector by `rhs` places /// let (a, b) = self.vec.split_at(rhs); /// let mut spun_vector: Vec<T> = vec![]; /// spun_vector.extend_from_slice(b); /// spun_vector.extend_from_slice(a); /// SpinVector { vec: spun_vector } /// } /// } /// /// fn main() { /// assert_eq!(SpinVector { vec: vec![0, 1, 2, 3, 4] } << 2, /// SpinVector { vec: vec![2, 3, 4, 0, 1] }); /// } /// ``` #[lang = "shl"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} << {RHS}`"] pub trait Shl<RHS> { /// The resulting type after applying the `<<` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `<<` operator #[stable(feature = "rust1", since = "1.0.0")] fn shl(self, rhs: RHS) -> Self::Output; } macro_rules! shl_impl { ($t:ty, $f:ty) => ( #[stable(feature = "rust1", since = "1.0.0")] impl Shl<$f> for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn shl(self, other: $f) -> $t { self << other } } forward_ref_binop! { impl Shl, shl for $t, $f } ) } macro_rules! shl_impl_all { ($($t:ty)*) => ($( shl_impl! { $t, u8 } shl_impl! { $t, u16 } shl_impl! { $t, u32 } shl_impl! { $t, u64 } shl_impl! { $t, u128 } shl_impl! { $t, usize } shl_impl! { $t, i8 } shl_impl! { $t, i16 } shl_impl! { $t, i32 } shl_impl! { $t, i64 } shl_impl! { $t, i128 } shl_impl! { $t, isize } )*) } shl_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 isize i128 } /// The right shift operator `>>`. /// /// # Examples /// /// An implementation of `Shr` that lifts the `>>` operation on integers to a /// `Scalar` struct. /// /// ``` /// use std::ops::Shr; /// /// #[derive(PartialEq, Debug)] /// struct Scalar(usize); /// /// impl Shr<Scalar> for Scalar { /// type Output = Self; /// /// fn shr(self, Scalar(rhs): Self) -> Scalar { /// let Scalar(lhs) = self; /// Scalar(lhs >> rhs) /// } /// } /// fn main() { /// assert_eq!(Scalar(16) >> Scalar(2), Scalar(4)); /// } /// ``` /// /// An implementation of `Shr` that spins a vector rightward by a given amount. /// /// ``` /// use std::ops::Shr; /// /// #[derive(PartialEq, Debug)] /// struct SpinVector<T: Clone> { /// vec: Vec<T>, /// } /// /// impl<T: Clone> Shr<usize> for SpinVector<T> { /// type Output = Self; /// /// fn shr(self, rhs: usize) -> SpinVector<T> { /// // rotate the vector by `rhs` places /// let (a, b) = self.vec.split_at(self.vec.len() - rhs); /// let mut spun_vector: Vec<T> = vec![]; /// spun_vector.extend_from_slice(b); /// spun_vector.extend_from_slice(a); /// SpinVector { vec: spun_vector } /// } /// } /// /// fn main() { /// assert_eq!(SpinVector { vec: vec![0, 1, 2, 3, 4] } >> 2, /// SpinVector { vec: vec![3, 4, 0, 1, 2] }); /// } /// ``` #[lang = "shr"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_on_unimplemented = "no implementation for `{Self} >> {RHS}`"] pub trait Shr<RHS> { /// The resulting type after applying the `>>` operator #[stable(feature = "rust1", since = "1.0.0")] type Output; /// The method for the `>>` operator #[stable(feature = "rust1", since = "1.0.0")] fn shr(self, rhs: RHS) -> Self::Output; } macro_rules! shr_impl { ($t:ty, $f:ty) => ( #[stable(feature = "rust1", since = "1.0.0")] impl Shr<$f> for $t { type Output = $t; #[inline] #[rustc_inherit_overflow_checks] fn shr(self, other: $f) -> $t { self >> other } } forward_ref_binop! { impl Shr, shr for $t, $f } ) } macro_rules! shr_impl_all { ($($t:ty)*) => ($( shr_impl! { $t, u8 } shr_impl! { $t, u16 } shr_impl! { $t, u32 } shr_impl! { $t, u64 } shr_impl! { $t, u128 } shr_impl! { $t, usize } shr_impl! { $t, i8 } shr_impl! { $t, i16 } shr_impl! { $t, i32 } shr_impl! { $t, i64 } shr_impl! { $t, i128 } shr_impl! { $t, isize } )*) } shr_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize } /// The addition assignment operator `+=`. /// /// # Examples /// /// This example creates a `Point` struct that implements the `AddAssign` /// trait, and then demonstrates add-assigning to a mutable `Point`. /// /// ``` /// use std::ops::AddAssign; /// /// #[derive(Debug)] /// struct Point { /// x: i32, /// y: i32, /// } /// /// impl AddAssign for Point { /// fn add_assign(&mut self, other: Point) { /// *self = Point { /// x: self.x + other.x, /// y: self.y + other.y, /// }; /// } /// } /// /// impl PartialEq for Point { /// fn eq(&self, other: &Self) -> bool { /// self.x == other.x && self.y == other.y /// } /// } /// /// let mut point = Point { x: 1, y: 0 }; /// point += Point { x: 2, y: 3 }; /// assert_eq!(point, Point { x: 3, y: 3 }); /// ``` #[lang = "add_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} += {Rhs}`"] pub trait AddAssign<Rhs=Self> { /// The method for the `+=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn add_assign(&mut self, rhs: Rhs); } macro_rules! add_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl AddAssign for $t { #[inline] #[rustc_inherit_overflow_checks] fn add_assign(&mut self, other: $t) { *self += other } } )+) } add_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The subtraction assignment operator `-=`. /// /// # Examples /// /// This example creates a `Point` struct that implements the `SubAssign` /// trait, and then demonstrates sub-assigning to a mutable `Point`. /// /// ``` /// use std::ops::SubAssign; /// /// #[derive(Debug)] /// struct Point { /// x: i32, /// y: i32, /// } /// /// impl SubAssign for Point { /// fn sub_assign(&mut self, other: Point) { /// *self = Point { /// x: self.x - other.x, /// y: self.y - other.y, /// }; /// } /// } /// /// impl PartialEq for Point { /// fn eq(&self, other: &Self) -> bool { /// self.x == other.x && self.y == other.y /// } /// } /// /// let mut point = Point { x: 3, y: 3 }; /// point -= Point { x: 2, y: 3 }; /// assert_eq!(point, Point {x: 1, y: 0}); /// ``` #[lang = "sub_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} -= {Rhs}`"] pub trait SubAssign<Rhs=Self> { /// The method for the `-=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn sub_assign(&mut self, rhs: Rhs); } macro_rules! sub_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl SubAssign for $t { #[inline] #[rustc_inherit_overflow_checks] fn sub_assign(&mut self, other: $t) { *self -= other } } )+) } sub_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The multiplication assignment operator `*=`. /// /// # Examples /// /// A trivial implementation of `MulAssign`. When `Foo *= Foo` happens, it ends up /// calling `mul_assign`, and therefore, `main` prints `Multiplying!`. /// /// ``` /// use std::ops::MulAssign; /// /// struct Foo; /// /// impl MulAssign for Foo { /// fn mul_assign(&mut self, _rhs: Foo) { /// println!("Multiplying!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo *= Foo; /// } /// ``` #[lang = "mul_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} *= {Rhs}`"] pub trait MulAssign<Rhs=Self> { /// The method for the `*=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn mul_assign(&mut self, rhs: Rhs); } macro_rules! mul_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl MulAssign for $t { #[inline] #[rustc_inherit_overflow_checks] fn mul_assign(&mut self, other: $t) { *self *= other } } )+) } mul_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The division assignment operator `/=`. /// /// # Examples /// /// A trivial implementation of `DivAssign`. When `Foo /= Foo` happens, it ends up /// calling `div_assign`, and therefore, `main` prints `Dividing!`. /// /// ``` /// use std::ops::DivAssign; /// /// struct Foo; /// /// impl DivAssign for Foo { /// fn div_assign(&mut self, _rhs: Foo) { /// println!("Dividing!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo /= Foo; /// } /// ``` #[lang = "div_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} /= {Rhs}`"] pub trait DivAssign<Rhs=Self> { /// The method for the `/=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn div_assign(&mut self, rhs: Rhs); } macro_rules! div_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl DivAssign for $t { #[inline] fn div_assign(&mut self, other: $t) { *self /= other } } )+) } div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The remainder assignment operator `%=`. /// /// # Examples /// /// A trivial implementation of `RemAssign`. When `Foo %= Foo` happens, it ends up /// calling `rem_assign`, and therefore, `main` prints `Remainder-ing!`. /// /// ``` /// use std::ops::RemAssign; /// /// struct Foo; /// /// impl RemAssign for Foo { /// fn rem_assign(&mut self, _rhs: Foo) { /// println!("Remainder-ing!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo %= Foo; /// } /// ``` #[lang = "rem_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} %= {Rhs}`"] pub trait RemAssign<Rhs=Self> { /// The method for the `%=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn rem_assign(&mut self, rhs: Rhs); } macro_rules! rem_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl RemAssign for $t { #[inline] fn rem_assign(&mut self, other: $t) { *self %= other } } )+) } rem_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 } /// The bitwise AND assignment operator `&=`. /// /// # Examples /// /// In this example, the `&=` operator is lifted to a trivial `Scalar` type. /// /// ``` /// use std::ops::BitAndAssign; /// /// #[derive(Debug, PartialEq)] /// struct Scalar(bool); /// /// impl BitAndAssign for Scalar { /// // rhs is the "right-hand side" of the expression `a &= b` /// fn bitand_assign(&mut self, rhs: Self) { /// *self = Scalar(self.0 & rhs.0) /// } /// } /// /// fn main() { /// let mut scalar = Scalar(true); /// scalar &= Scalar(true); /// assert_eq!(scalar, Scalar(true)); /// /// let mut scalar = Scalar(true); /// scalar &= Scalar(false); /// assert_eq!(scalar, Scalar(false)); /// /// let mut scalar = Scalar(false); /// scalar &= Scalar(true); /// assert_eq!(scalar, Scalar(false)); /// /// let mut scalar = Scalar(false); /// scalar &= Scalar(false); /// assert_eq!(scalar, Scalar(false)); /// } /// ``` /// /// In this example, the `BitAndAssign` trait is implemented for a /// `BooleanVector` struct. /// /// ``` /// use std::ops::BitAndAssign; /// /// #[derive(Debug, PartialEq)] /// struct BooleanVector(Vec<bool>); /// /// impl BitAndAssign for BooleanVector { /// // rhs is the "right-hand side" of the expression `a &= b` /// fn bitand_assign(&mut self, rhs: Self) { /// assert_eq!(self.0.len(), rhs.0.len()); /// *self = BooleanVector(self.0 /// .iter() /// .zip(rhs.0.iter()) /// .map(|(x, y)| *x && *y) /// .collect()); /// } /// } /// /// fn main() { /// let mut bv = BooleanVector(vec![true, true, false, false]); /// bv &= BooleanVector(vec![true, false, true, false]); /// let expected = BooleanVector(vec![true, false, false, false]); /// assert_eq!(bv, expected); /// } /// ``` #[lang = "bitand_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} &= {Rhs}`"] pub trait BitAndAssign<Rhs=Self> { /// The method for the `&=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn bitand_assign(&mut self, rhs: Rhs); } macro_rules! bitand_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl BitAndAssign for $t { #[inline] fn bitand_assign(&mut self, other: $t) { *self &= other } } )+) } bitand_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The bitwise OR assignment operator `|=`. /// /// # Examples /// /// A trivial implementation of `BitOrAssign`. When `Foo |= Foo` happens, it ends up /// calling `bitor_assign`, and therefore, `main` prints `Bitwise Or-ing!`. /// /// ``` /// use std::ops::BitOrAssign; /// /// struct Foo; /// /// impl BitOrAssign for Foo { /// fn bitor_assign(&mut self, _rhs: Foo) { /// println!("Bitwise Or-ing!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo |= Foo; /// } /// ``` #[lang = "bitor_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} |= {Rhs}`"] pub trait BitOrAssign<Rhs=Self> { /// The method for the `|=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn bitor_assign(&mut self, rhs: Rhs); } macro_rules! bitor_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl BitOrAssign for $t { #[inline] fn bitor_assign(&mut self, other: $t) { *self |= other } } )+) } bitor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The bitwise XOR assignment operator `^=`. /// /// # Examples /// /// A trivial implementation of `BitXorAssign`. When `Foo ^= Foo` happens, it ends up /// calling `bitxor_assign`, and therefore, `main` prints `Bitwise Xor-ing!`. /// /// ``` /// use std::ops::BitXorAssign; /// /// struct Foo; /// /// impl BitXorAssign for Foo { /// fn bitxor_assign(&mut self, _rhs: Foo) { /// println!("Bitwise Xor-ing!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo ^= Foo; /// } /// ``` #[lang = "bitxor_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} ^= {Rhs}`"] pub trait BitXorAssign<Rhs=Self> { /// The method for the `^=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn bitxor_assign(&mut self, rhs: Rhs); } macro_rules! bitxor_assign_impl { ($($t:ty)+) => ($( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl BitXorAssign for $t { #[inline] fn bitxor_assign(&mut self, other: $t) { *self ^= other } } )+) } bitxor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } /// The left shift assignment operator `<<=`. /// /// # Examples /// /// A trivial implementation of `ShlAssign`. When `Foo <<= Foo` happens, it ends up /// calling `shl_assign`, and therefore, `main` prints `Shifting left!`. /// /// ``` /// use std::ops::ShlAssign; /// /// struct Foo; /// /// impl ShlAssign<Foo> for Foo { /// fn shl_assign(&mut self, _rhs: Foo) { /// println!("Shifting left!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo <<= Foo; /// } /// ``` #[lang = "shl_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} <<= {Rhs}`"] pub trait ShlAssign<Rhs> { /// The method for the `<<=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn shl_assign(&mut self, rhs: Rhs); } macro_rules! shl_assign_impl { ($t:ty, $f:ty) => ( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl ShlAssign<$f> for $t { #[inline] #[rustc_inherit_overflow_checks] fn shl_assign(&mut self, other: $f) { *self <<= other } } ) } macro_rules! shl_assign_impl_all { ($($t:ty)*) => ($( shl_assign_impl! { $t, u8 } shl_assign_impl! { $t, u16 } shl_assign_impl! { $t, u32 } shl_assign_impl! { $t, u64 } shl_assign_impl! { $t, u128 } shl_assign_impl! { $t, usize } shl_assign_impl! { $t, i8 } shl_assign_impl! { $t, i16 } shl_assign_impl! { $t, i32 } shl_assign_impl! { $t, i64 } shl_assign_impl! { $t, i128 } shl_assign_impl! { $t, isize } )*) } shl_assign_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize } /// The right shift assignment operator `>>=`. /// /// # Examples /// /// A trivial implementation of `ShrAssign`. When `Foo >>= Foo` happens, it ends up /// calling `shr_assign`, and therefore, `main` prints `Shifting right!`. /// /// ``` /// use std::ops::ShrAssign; /// /// struct Foo; /// /// impl ShrAssign<Foo> for Foo { /// fn shr_assign(&mut self, _rhs: Foo) { /// println!("Shifting right!"); /// } /// } /// /// # #[allow(unused_assignments)] /// fn main() { /// let mut foo = Foo; /// foo >>= Foo; /// } /// ``` #[lang = "shr_assign"] #[stable(feature = "op_assign_traits", since = "1.8.0")] #[rustc_on_unimplemented = "no implementation for `{Self} >>= {Rhs}`"] pub trait ShrAssign<Rhs=Self> { /// The method for the `>>=` operator #[stable(feature = "op_assign_traits", since = "1.8.0")] fn shr_assign(&mut self, rhs: Rhs); } macro_rules! shr_assign_impl { ($t:ty, $f:ty) => ( #[stable(feature = "op_assign_traits", since = "1.8.0")] impl ShrAssign<$f> for $t { #[inline] #[rustc_inherit_overflow_checks] fn shr_assign(&mut self, other: $f) { *self >>= other } } ) } macro_rules! shr_assign_impl_all { ($($t:ty)*) => ($( shr_assign_impl! { $t, u8 } shr_assign_impl! { $t, u16 } shr_assign_impl! { $t, u32 } shr_assign_impl! { $t, u64 } shr_assign_impl! { $t, u128 } shr_assign_impl! { $t, usize } shr_assign_impl! { $t, i8 } shr_assign_impl! { $t, i16 } shr_assign_impl! { $t, i32 } shr_assign_impl! { $t, i64 } shr_assign_impl! { $t, i128 } shr_assign_impl! { $t, isize } )*) } shr_assign_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize } /// The `Index` trait is used to specify the functionality of indexing operations /// like `container[index]` when used in an immutable context. /// /// `container[index]` is actually syntactic sugar for `*container.index(index)`, /// but only when used as an immutable value. If a mutable value is requested, /// [`IndexMut`] is used instead. This allows nice things such as /// `let value = v[index]` if `value` implements [`Copy`]. /// /// [`IndexMut`]: ../../std/ops/trait.IndexMut.html /// [`Copy`]: ../../std/marker/trait.Copy.html /// /// # Examples /// /// The following example implements `Index` on a read-only `NucleotideCount` /// container, enabling individual counts to be retrieved with index syntax. /// /// ``` /// use std::ops::Index; /// /// enum Nucleotide { /// A, /// C, /// G, /// T, /// } /// /// struct NucleotideCount { /// a: usize, /// c: usize, /// g: usize, /// t: usize, /// } /// /// impl Index<Nucleotide> for NucleotideCount { /// type Output = usize; /// /// fn index(&self, nucleotide: Nucleotide) -> &usize { /// match nucleotide { /// Nucleotide::A => &self.a, /// Nucleotide::C => &self.c, /// Nucleotide::G => &self.g, /// Nucleotide::T => &self.t, /// } /// } /// } /// /// let nucleotide_count = NucleotideCount {a: 14, c: 9, g: 10, t: 12}; /// assert_eq!(nucleotide_count[Nucleotide::A], 14); /// assert_eq!(nucleotide_count[Nucleotide::C], 9); /// assert_eq!(nucleotide_count[Nucleotide::G], 10); /// assert_eq!(nucleotide_count[Nucleotide::T], 12); /// ``` #[lang = "index"] #[rustc_on_unimplemented = "the type `{Self}` cannot be indexed by `{Idx}`"] #[stable(feature = "rust1", since = "1.0.0")] pub trait Index<Idx: ?Sized> { /// The returned type after indexing #[stable(feature = "rust1", since = "1.0.0")] type Output: ?Sized; /// The method for the indexing (`container[index]`) operation #[stable(feature = "rust1", since = "1.0.0")] fn index(&self, index: Idx) -> &Self::Output; } /// The `IndexMut` trait is used to specify the functionality of indexing /// operations like `container[index]` when used in a mutable context. /// /// `container[index]` is actually syntactic sugar for /// `*container.index_mut(index)`, but only when used as a mutable value. If /// an immutable value is requested, the [`Index`] trait is used instead. This /// allows nice things such as `v[index] = value` if `value` implements [`Copy`]. /// /// [`Index`]: ../../std/ops/trait.Index.html /// [`Copy`]: ../../std/marker/trait.Copy.html /// /// # Examples /// /// A very simple implementation of a `Balance` struct that has two sides, where /// each can be indexed mutably and immutably. /// /// ``` /// use std::ops::{Index,IndexMut}; /// /// #[derive(Debug)] /// enum Side { /// Left, /// Right, /// } /// /// #[derive(Debug, PartialEq)] /// enum Weight { /// Kilogram(f32), /// Pound(f32), /// } /// /// struct Balance { /// pub left: Weight, /// pub right:Weight, /// } /// /// impl Index<Side> for Balance { /// type Output = Weight; /// /// fn index<'a>(&'a self, index: Side) -> &'a Weight { /// println!("Accessing {:?}-side of balance immutably", index); /// match index { /// Side::Left => &self.left, /// Side::Right => &self.right, /// } /// } /// } /// /// impl IndexMut<Side> for Balance { /// fn index_mut<'a>(&'a mut self, index: Side) -> &'a mut Weight { /// println!("Accessing {:?}-side of balance mutably", index); /// match index { /// Side::Left => &mut self.left, /// Side::Right => &mut self.right, /// } /// } /// } /// /// fn main() { /// let mut balance = Balance { /// right: Weight::Kilogram(2.5), /// left: Weight::Pound(1.5), /// }; /// /// // In this case balance[Side::Right] is sugar for /// // *balance.index(Side::Right), since we are only reading /// // balance[Side::Right], not writing it. /// assert_eq!(balance[Side::Right],Weight::Kilogram(2.5)); /// /// // However in this case balance[Side::Left] is sugar for /// // *balance.index_mut(Side::Left), since we are writing /// // balance[Side::Left]. /// balance[Side::Left] = Weight::Kilogram(3.0); /// } /// ``` #[lang = "index_mut"] #[rustc_on_unimplemented = "the type `{Self}` cannot be mutably indexed by `{Idx}`"] #[stable(feature = "rust1", since = "1.0.0")] pub trait IndexMut<Idx: ?Sized>: Index<Idx> { /// The method for the mutable indexing (`container[index]`) operation #[stable(feature = "rust1", since = "1.0.0")] fn index_mut(&mut self, index: Idx) -> &mut Self::Output; } /// An unbounded range. Use `..` (two dots) for its shorthand. /// /// Its primary use case is slicing index. It cannot serve as an iterator /// because it doesn't have a starting point. /// /// # Examples /// /// The `..` syntax is a `RangeFull`: /// /// ``` /// 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: /// /// ```ignore /// for i in .. { /// // ... /// } /// ``` /// /// Used as a slicing index, `RangeFull` produces the full array as a slice. /// /// ``` /// let arr = [0, 1, 2, 3]; /// assert_eq!(arr[ .. ], [0,1,2,3]); // RangeFull /// assert_eq!(arr[ ..3], [0,1,2 ]); /// assert_eq!(arr[1.. ], [ 1,2,3]); /// assert_eq!(arr[1..3], [ 1,2 ]); /// ``` #[derive(Copy, Clone, PartialEq, Eq, Hash)] #[stable(feature = "rust1", since = "1.0.0")] pub struct RangeFull; #[stable(feature = "rust1", since = "1.0.0")] impl fmt::Debug for RangeFull { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "..") } } /// A (half-open) range which is bounded at both ends: { x | start <= x < end }. /// Use `start..end` (two dots) for its shorthand. /// /// See the [`contains`](#method.contains) method for its characterization. /// /// # Examples /// /// ``` /// fn main() { /// 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 /// } /// ``` #[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186 #[stable(feature = "rust1", since = "1.0.0")] pub struct Range<Idx> { /// The lower bound of the range (inclusive). #[stable(feature = "rust1", since = "1.0.0")] pub start: Idx, /// The upper bound of the range (exclusive). #[stable(feature = "rust1", since = "1.0.0")] pub end: Idx, } #[stable(feature = "rust1", since = "1.0.0")] impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "{:?}..{:?}", self.start, self.end) } } #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")] impl<Idx: PartialOrd<Idx>> Range<Idx> { /// # 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)); /// } /// ``` 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. /// /// See the [`contains`](#method.contains) method for its characterization. /// /// 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. /// /// # Examples /// /// ``` /// fn main() { /// 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 ]); /// } /// ``` #[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186 #[stable(feature = "rust1", since = "1.0.0")] pub struct RangeFrom<Idx> { /// The lower bound of the range (inclusive). #[stable(feature = "rust1", since = "1.0.0")] pub start: Idx, } #[stable(feature = "rust1", since = "1.0.0")] impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "{:?}..", self.start) } } #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")] impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> { /// # Examples /// /// ``` /// #![feature(range_contains)] /// 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. /// /// See the [`contains`](#method.contains) method for its characterization. /// /// It cannot serve as an iterator because it doesn't have a starting point. /// /// # Examples /// /// The `..{integer}` syntax is a `RangeTo`: /// /// ``` /// 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: /// /// ```ignore /// for i in ..5 { /// // ... /// } /// ``` /// /// When used as a slicing index, `RangeTo` produces a slice of all array /// elements before the index indicated by `end`. /// /// ``` /// let arr = [0, 1, 2, 3]; /// assert_eq!(arr[ .. ], [0,1,2,3]); /// assert_eq!(arr[ ..3], [0,1,2 ]); // RangeTo /// assert_eq!(arr[1.. ], [ 1,2,3]); /// assert_eq!(arr[1..3], [ 1,2 ]); /// ``` #[derive(Copy, Clone, PartialEq, Eq, Hash)] #[stable(feature = "rust1", since = "1.0.0")] pub struct RangeTo<Idx> { /// The upper bound of the range (exclusive). #[stable(feature = "rust1", since = "1.0.0")] pub end: Idx, } #[stable(feature = "rust1", since = "1.0.0")] impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "..{:?}", self.end) } } #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")] impl<Idx: PartialOrd<Idx>> RangeTo<Idx> { /// # Examples /// /// ``` /// #![feature(range_contains)] /// 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. /// /// See the [`contains`](#method.contains) method for its characterization. /// /// # 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 /// } /// ``` #[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] pub struct RangeInclusive<Idx> { /// The lower bound of the range (inclusive). #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] pub start: Idx, /// The upper bound of the range (inclusive). #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] pub end: Idx, } #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "{:?}...{:?}", self.start, self.end) } } #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")] impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> { /// # 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)); /// } /// ``` 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. /// /// See the [`contains`](#method.contains) method for its characterization. /// /// It cannot serve as an iterator because it doesn't have a starting point. /// /// # Examples /// /// The `...{integer}` 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 /// `for` loop directly. This won't compile: /// /// ```ignore /// for i in ...5 { /// // ... /// } /// ``` /// /// 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)] /// let arr = [0, 1, 2, 3]; /// assert_eq!(arr[ ...2], [0,1,2 ]); // RangeToInclusive /// assert_eq!(arr[1...2], [ 1,2 ]); /// ``` #[derive(Copy, Clone, PartialEq, Eq, Hash)] #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] pub struct RangeToInclusive<Idx> { /// The upper bound of the range (inclusive) #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] pub end: Idx, } #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")] impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { write!(fmt, "...{:?}", self.end) } } #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")] impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> { /// # Examples /// /// ``` /// #![feature(range_contains,inclusive_range_syntax)] /// 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) } } // RangeToInclusive<Idx> cannot impl From<RangeTo<Idx>> // because underflow would be possible with (..0).into() /// The `Deref` trait is used to specify the functionality of dereferencing /// operations, like `*v`. /// /// `Deref` also enables ['`Deref` coercions'][coercions]. /// /// [coercions]: ../../book/deref-coercions.html /// /// # Examples /// /// A struct with a single field which is accessible via dereferencing the /// struct. /// /// ``` /// use std::ops::Deref; /// /// struct DerefExample<T> { /// value: T /// } /// /// impl<T> Deref for DerefExample<T> { /// type Target = T; /// /// fn deref(&self) -> &T { /// &self.value /// } /// } /// /// fn main() { /// let x = DerefExample { value: 'a' }; /// assert_eq!('a', *x); /// } /// ``` #[lang = "deref"] #[stable(feature = "rust1", since = "1.0.0")] pub trait Deref { /// The resulting type after dereferencing #[stable(feature = "rust1", since = "1.0.0")] type Target: ?Sized; /// The method called to dereference a value #[stable(feature = "rust1", since = "1.0.0")] fn deref(&self) -> &Self::Target; } #[stable(feature = "rust1", since = "1.0.0")] impl<'a, T: ?Sized> Deref for &'a T { type Target = T; fn deref(&self) -> &T { *self } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a, T: ?Sized> Deref for &'a mut T { type Target = T; fn deref(&self) -> &T { *self } } /// The `DerefMut` trait is used to specify the functionality of dereferencing /// mutably like `*v = 1;` /// /// `DerefMut` also enables ['`Deref` coercions'][coercions]. /// /// [coercions]: ../../book/deref-coercions.html /// /// # Examples /// /// A struct with a single field which is modifiable via dereferencing the /// struct. /// /// ``` /// use std::ops::{Deref, DerefMut}; /// /// struct DerefMutExample<T> { /// value: T /// } /// /// impl<T> Deref for DerefMutExample<T> { /// type Target = T; /// /// fn deref(&self) -> &T { /// &self.value /// } /// } /// /// impl<T> DerefMut for DerefMutExample<T> { /// fn deref_mut(&mut self) -> &mut T { /// &mut self.value /// } /// } /// /// fn main() { /// let mut x = DerefMutExample { value: 'a' }; /// *x = 'b'; /// assert_eq!('b', *x); /// } /// ``` #[lang = "deref_mut"] #[stable(feature = "rust1", since = "1.0.0")] pub trait DerefMut: Deref { /// The method called to mutably dereference a value #[stable(feature = "rust1", since = "1.0.0")] fn deref_mut(&mut self) -> &mut Self::Target; } #[stable(feature = "rust1", since = "1.0.0")] impl<'a, T: ?Sized> DerefMut for &'a mut T { fn deref_mut(&mut self) -> &mut T { *self } } /// A version of the call operator that takes an immutable receiver. /// /// # Examples /// /// Closures automatically implement this trait, which allows them to be /// invoked. Note, however, that `Fn` takes an immutable reference to any /// captured variables. To take a mutable capture, implement [`FnMut`], and to /// consume the capture, implement [`FnOnce`]. /// /// [`FnMut`]: trait.FnMut.html /// [`FnOnce`]: trait.FnOnce.html /// /// ``` /// let square = |x| x * x; /// assert_eq!(square(5), 25); /// ``` /// /// Closures can also be passed to higher-level functions through a `Fn` /// parameter (or a `FnMut` or `FnOnce` parameter, which are supertraits of /// `Fn`). /// /// ``` /// fn call_with_one<F>(func: F) -> usize /// where F: Fn(usize) -> usize { /// func(1) /// } /// /// let double = |x| x * 2; /// assert_eq!(call_with_one(double), 2); /// ``` #[lang = "fn"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_paren_sugar] #[fundamental] // so that regex can rely that `&str: !FnMut` pub trait Fn<Args> : FnMut<Args> { /// This is called when the call operator is used. #[unstable(feature = "fn_traits", issue = "29625")] extern "rust-call" fn call(&self, args: Args) -> Self::Output; } /// A version of the call operator that takes a mutable receiver. /// /// # Examples /// /// Closures that mutably capture variables automatically implement this trait, /// which allows them to be invoked. /// /// ``` /// let mut x = 5; /// { /// let mut square_x = || x *= x; /// square_x(); /// } /// assert_eq!(x, 25); /// ``` /// /// Closures can also be passed to higher-level functions through a `FnMut` /// parameter (or a `FnOnce` parameter, which is a supertrait of `FnMut`). /// /// ``` /// fn do_twice<F>(mut func: F) /// where F: FnMut() /// { /// func(); /// func(); /// } /// /// let mut x: usize = 1; /// { /// let add_two_to_x = || x += 2; /// do_twice(add_two_to_x); /// } /// /// assert_eq!(x, 5); /// ``` #[lang = "fn_mut"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_paren_sugar] #[fundamental] // so that regex can rely that `&str: !FnMut` pub trait FnMut<Args> : FnOnce<Args> { /// This is called when the call operator is used. #[unstable(feature = "fn_traits", issue = "29625")] extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output; } /// A version of the call operator that takes a by-value receiver. /// /// # Examples /// /// By-value closures automatically implement this trait, which allows them to /// be invoked. /// /// ``` /// let x = 5; /// let square_x = move || x * x; /// assert_eq!(square_x(), 25); /// ``` /// /// By-value Closures can also be passed to higher-level functions through a /// `FnOnce` parameter. /// /// ``` /// fn consume_with_relish<F>(func: F) /// where F: FnOnce() -> String /// { /// // `func` consumes its captured variables, so it cannot be run more /// // than once /// println!("Consumed: {}", func()); /// /// println!("Delicious!"); /// /// // Attempting to invoke `func()` again will throw a `use of moved /// // value` error for `func` /// } /// /// let x = String::from("x"); /// let consume_and_return_x = move || x; /// consume_with_relish(consume_and_return_x); /// /// // `consume_and_return_x` can no longer be invoked at this point /// ``` #[lang = "fn_once"] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_paren_sugar] #[fundamental] // so that regex can rely that `&str: !FnMut` pub trait FnOnce<Args> { /// The returned type after the call operator is used. #[stable(feature = "fn_once_output", since = "1.12.0")] type Output; /// This is called when the call operator is used. #[unstable(feature = "fn_traits", issue = "29625")] extern "rust-call" fn call_once(self, args: Args) -> Self::Output; } mod impls { #[stable(feature = "rust1", since = "1.0.0")] impl<'a,A,F:?Sized> Fn<A> for &'a F where F : Fn<A> { extern "rust-call" fn call(&self, args: A) -> F::Output { (**self).call(args) } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a,A,F:?Sized> FnMut<A> for &'a F where F : Fn<A> { extern "rust-call" fn call_mut(&mut self, args: A) -> F::Output { (**self).call(args) } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a,A,F:?Sized> FnOnce<A> for &'a F where F : Fn<A> { type Output = F::Output; extern "rust-call" fn call_once(self, args: A) -> F::Output { (*self).call(args) } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a,A,F:?Sized> FnMut<A> for &'a mut F where F : FnMut<A> { extern "rust-call" fn call_mut(&mut self, args: A) -> F::Output { (*self).call_mut(args) } } #[stable(feature = "rust1", since = "1.0.0")] impl<'a,A,F:?Sized> FnOnce<A> for &'a mut F where F : FnMut<A> { type Output = F::Output; extern "rust-call" fn call_once(mut self, args: A) -> F::Output { (*self).call_mut(args) } } } /// Trait that indicates that this is a pointer or a wrapper for one, /// where unsizing can be performed on the pointee. /// /// See the [DST coercion RfC][dst-coerce] and [the nomicon entry on coercion][nomicon-coerce] /// for more details. /// /// For builtin pointer types, pointers to `T` will coerce to pointers to `U` if `T: Unsize<U>` /// by converting from a thin pointer to a fat pointer. /// /// For custom types, the coercion here works by coercing `Foo<T>` to `Foo<U>` /// provided an impl of `CoerceUnsized<Foo<U>> for Foo<T>` exists. /// Such an impl can only be written if `Foo<T>` has only a single non-phantomdata /// field involving `T`. If the type of that field is `Bar<T>`, an implementation /// of `CoerceUnsized<Bar<U>> for Bar<T>` must exist. The coercion will work by /// by coercing the `Bar<T>` field into `Bar<U>` and filling in the rest of the fields /// from `Foo<T>` to create a `Foo<U>`. This will effectively drill down to a pointer /// field and coerce that. /// /// Generally, for smart pointers you will implement /// `CoerceUnsized<Ptr<U>> for Ptr<T> where T: Unsize<U>, U: ?Sized`, with an /// optional `?Sized` bound on `T` itself. For wrapper types that directly embed `T` /// like `Cell<T>` and `RefCell<T>`, you /// can directly implement `CoerceUnsized<Wrap<U>> for Wrap<T> where T: CoerceUnsized<U>`. /// This will let coercions of types like `Cell<Box<T>>` work. /// /// [`Unsize`][unsize] is used to mark types which can be coerced to DSTs if behind /// pointers. It is implemented automatically by the compiler. /// /// [dst-coerce]: https://github.com/rust-lang/rfcs/blob/master/text/0982-dst-coercion.md /// [unsize]: ../marker/trait.Unsize.html /// [nomicon-coerce]: ../../nomicon/coercions.html #[unstable(feature = "coerce_unsized", issue = "27732")] #[lang="coerce_unsized"] pub trait CoerceUnsized<T> { // Empty. } // &mut T -> &mut U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<&'a mut U> for &'a mut T {} // &mut T -> &U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, 'b: 'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b mut T {} // &mut T -> *mut U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for &'a mut T {} // &mut T -> *const U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a mut T {} // &T -> &U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, 'b: 'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {} // &T -> *const U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<'a, T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a T {} // *mut T -> *mut U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {} // *mut T -> *const U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *mut T {} // *const T -> *const U #[unstable(feature = "coerce_unsized", issue = "27732")] impl<T: ?Sized+Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *const T {} /// Both `PLACE <- EXPR` and `box EXPR` desugar into expressions /// that allocate an intermediate "place" that holds uninitialized /// state. The desugaring evaluates EXPR, and writes the result at /// the address returned by the `pointer` method of this trait. /// /// A `Place` can be thought of as a special representation for a /// hypothetical `&uninit` reference (which Rust cannot currently /// express directly). That is, it represents a pointer to /// uninitialized storage. /// /// The client is responsible for two steps: First, initializing the /// payload (it can access its address via `pointer`). Second, /// converting the agent to an instance of the owning pointer, via the /// appropriate `finalize` method (see the `InPlace`. /// /// If evaluating EXPR fails, then it is up to the destructor for the /// implementation of Place to clean up any intermediate state /// (e.g. deallocate box storage, pop a stack, etc). #[unstable(feature = "placement_new_protocol", issue = "27779")] pub trait Place<Data: ?Sized> { /// Returns the address where the input value will be written. /// Note that the data at this address is generally uninitialized, /// and thus one should use `ptr::write` for initializing it. fn pointer(&mut self) -> *mut Data; } /// Interface to implementations of `PLACE <- EXPR`. /// /// `PLACE <- EXPR` effectively desugars into: /// /// ```rust,ignore /// let p = PLACE; /// let mut place = Placer::make_place(p); /// let raw_place = Place::pointer(&mut place); /// let value = EXPR; /// unsafe { /// std::ptr::write(raw_place, value); /// InPlace::finalize(place) /// } /// ``` /// /// The type of `PLACE <- EXPR` is derived from the type of `PLACE`; /// if the type of `PLACE` is `P`, then the final type of the whole /// expression is `P::Place::Owner` (see the `InPlace` and `Boxed` /// traits). /// /// Values for types implementing this trait usually are transient /// intermediate values (e.g. the return value of `Vec::emplace_back`) /// or `Copy`, since the `make_place` method takes `self` by value. #[unstable(feature = "placement_new_protocol", issue = "27779")] pub trait Placer<Data: ?Sized> { /// `Place` is the intermedate agent guarding the /// uninitialized state for `Data`. type Place: InPlace<Data>; /// Creates a fresh place from `self`. fn make_place(self) -> Self::Place; } /// Specialization of `Place` trait supporting `PLACE <- EXPR`. #[unstable(feature = "placement_new_protocol", issue = "27779")] pub trait InPlace<Data: ?Sized>: Place<Data> { /// `Owner` is the type of the end value of `PLACE <- EXPR` /// /// Note that when `PLACE <- EXPR` is solely used for /// side-effecting an existing data-structure, /// e.g. `Vec::emplace_back`, then `Owner` need not carry any /// information at all (e.g. it can be the unit type `()` in that /// case). type Owner; /// Converts self into the final value, shifting /// deallocation/cleanup responsibilities (if any remain), over to /// the returned instance of `Owner` and forgetting self. unsafe fn finalize(self) -> Self::Owner; } /// Core trait for the `box EXPR` form. /// /// `box EXPR` effectively desugars into: /// /// ```rust,ignore /// let mut place = BoxPlace::make_place(); /// let raw_place = Place::pointer(&mut place); /// let value = EXPR; /// unsafe { /// ::std::ptr::write(raw_place, value); /// Boxed::finalize(place) /// } /// ``` /// /// The type of `box EXPR` is supplied from its surrounding /// context; in the above expansion, the result type `T` is used /// to determine which implementation of `Boxed` to use, and that /// `<T as Boxed>` in turn dictates determines which /// implementation of `BoxPlace` to use, namely: /// `<<T as Boxed>::Place as BoxPlace>`. #[unstable(feature = "placement_new_protocol", issue = "27779")] pub trait Boxed { /// The kind of data that is stored in this kind of box. type Data; /* (`Data` unused b/c cannot yet express below bound.) */ /// The place that will negotiate the storage of the data. type Place: BoxPlace<Self::Data>; /// Converts filled place into final owning value, shifting /// deallocation/cleanup responsibilities (if any remain), over to /// returned instance of `Self` and forgetting `filled`. unsafe fn finalize(filled: Self::Place) -> Self; } /// Specialization of `Place` trait supporting `box EXPR`. #[unstable(feature = "placement_new_protocol", issue = "27779")] pub trait BoxPlace<Data: ?Sized> : Place<Data> { /// Creates a globally fresh place. fn make_place() -> Self; } /// A trait for types which have success and error states and are meant to work /// with the question mark operator. /// When the `?` operator is used with a value, whether the value is in the /// success or error state is determined by calling `translate`. /// /// This trait is **very** experimental, it will probably be iterated on heavily /// before it is stabilised. Implementors should expect change. Users of `?` /// should not rely on any implementations of `Carrier` other than `Result`, /// i.e., you should not expect `?` to continue to work with `Option`, etc. #[unstable(feature = "question_mark_carrier", issue = "31436")] pub trait Carrier { /// The type of the value when computation succeeds. type Success; /// The type of the value when computation errors out. type Error; /// Create a `Carrier` from a success value. fn from_success(_: Self::Success) -> Self; /// Create a `Carrier` from an error value. fn from_error(_: Self::Error) -> Self; /// Translate this `Carrier` to another implementation of `Carrier` with the /// same associated types. fn translate<T>(self) -> T where T: Carrier<Success=Self::Success, Error=Self::Error>; } #[unstable(feature = "question_mark_carrier", issue = "31436")] impl<U, V> Carrier for Result<U, V> { type Success = U; type Error = V; fn from_success(u: U) -> Result<U, V> { Ok(u) } fn from_error(e: V) -> Result<U, V> { Err(e) } fn translate<T>(self) -> T where T: Carrier<Success=U, Error=V> { match self { Ok(u) => T::from_success(u), Err(e) => T::from_error(e), } } } struct _DummyErrorType; impl Carrier for _DummyErrorType { type Success = (); type Error = (); fn from_success(_: ()) -> _DummyErrorType { _DummyErrorType } fn from_error(_: ()) -> _DummyErrorType { _DummyErrorType } fn translate<T>(self) -> T where T: Carrier<Success=(), Error=()> { T::from_success(()) } }