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// Copyright 2015 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. #[doc(primitive = "bool")] // /// The boolean type. /// mod prim_bool { } #[doc(primitive = "char")] // /// A character type. /// /// The `char` type represents a single character. More specifically, since /// 'character' isn't a well-defined concept in Unicode, `char` is a '[Unicode /// scalar value]', which is similar to, but not the same as, a '[Unicode code /// point]'. /// /// [Unicode scalar value]: http://www.unicode.org/glossary/#unicode_scalar_value /// [Unicode code point]: http://www.unicode.org/glossary/#code_point /// /// This documentation describes a number of methods and trait implementations on the /// `char` type. For technical reasons, there is additional, separate /// documentation in [the `std::char` module](char/index.html) as well. /// /// # Representation /// /// `char` is always four bytes in size. This is a different representation than /// a given character would have as part of a [`String`], for example: /// /// ``` /// let v = vec!['h', 'e', 'l', 'l', 'o']; /// /// // five elements times four bytes for each element /// assert_eq!(20, v.len() * std::mem::size_of::<char>()); /// /// let s = String::from("hello"); /// /// // five elements times one byte per element /// assert_eq!(5, s.len() * std::mem::size_of::<u8>()); /// ``` /// /// [`String`]: string/struct.String.html /// /// As always, remember that a human intuition for 'character' may not map to /// Unicode's definitions. For example, emoji symbols such as '❤️' are more than /// one byte; ❤️ in particular is six: /// /// ``` /// let s = String::from("❤️"); /// /// // six bytes times one byte for each element /// assert_eq!(6, s.len() * std::mem::size_of::<u8>()); /// ``` /// /// This also means it won't fit into a `char`, and so trying to create a /// literal with `let heart = '❤️';` gives an error: /// /// ```text /// error: character literal may only contain one codepoint: '❤ /// let heart = '❤️'; /// ^~ /// ``` /// /// Another implication of this is that if you want to do per-`char`acter /// processing, it can end up using a lot more memory: /// /// ``` /// let s = String::from("love: ❤️"); /// let v: Vec<char> = s.chars().collect(); /// /// assert_eq!(12, s.len() * std::mem::size_of::<u8>()); /// assert_eq!(32, v.len() * std::mem::size_of::<char>()); /// ``` /// /// Or may give you results you may not expect: /// /// ``` /// let s = String::from("❤️"); /// /// let mut iter = s.chars(); /// /// // we get two chars out of a single ❤️ /// assert_eq!(Some('\u{2764}'), iter.next()); /// assert_eq!(Some('\u{fe0f}'), iter.next()); /// assert_eq!(None, iter.next()); /// ``` mod prim_char { } #[doc(primitive = "unit")] // /// The `()` type, sometimes called "unit" or "nil". /// /// The `()` type has exactly one value `()`, and is used when there /// is no other meaningful value that could be returned. `()` is most /// commonly seen implicitly: functions without a `-> ...` implicitly /// have return type `()`, that is, these are equivalent: /// /// ```rust /// fn long() -> () {} /// /// fn short() {} /// ``` /// /// The semicolon `;` can be used to discard the result of an /// expression at the end of a block, making the expression (and thus /// the block) evaluate to `()`. For example, /// /// ```rust /// fn returns_i64() -> i64 { /// 1i64 /// } /// fn returns_unit() { /// 1i64; /// } /// /// let is_i64 = { /// returns_i64() /// }; /// let is_unit = { /// returns_i64(); /// }; /// ``` /// mod prim_unit { } #[doc(primitive = "pointer")] // /// Raw, unsafe pointers, `*const T`, and `*mut T`. /// /// Working with raw pointers in Rust is uncommon, /// typically limited to a few patterns. /// /// Use the `null` function to create null pointers, and the `is_null` method /// of the `*const T` type to check for null. The `*const T` type also defines /// the `offset` method, for pointer math. /// /// # Common ways to create raw pointers /// /// ## 1. Coerce a reference (`&T`) or mutable reference (`&mut T`). /// /// ``` /// let my_num: i32 = 10; /// let my_num_ptr: *const i32 = &my_num; /// let mut my_speed: i32 = 88; /// let my_speed_ptr: *mut i32 = &mut my_speed; /// ``` /// /// To get a pointer to a boxed value, dereference the box: /// /// ``` /// let my_num: Box<i32> = Box::new(10); /// let my_num_ptr: *const i32 = &*my_num; /// let mut my_speed: Box<i32> = Box::new(88); /// let my_speed_ptr: *mut i32 = &mut *my_speed; /// ``` /// /// This does not take ownership of the original allocation /// and requires no resource management later, /// but you must not use the pointer after its lifetime. /// /// ## 2. Consume a box (`Box<T>`). /// /// The `into_raw` function consumes a box and returns /// the raw pointer. It doesn't destroy `T` or deallocate any memory. /// /// ``` /// let my_speed: Box<i32> = Box::new(88); /// let my_speed: *mut i32 = Box::into_raw(my_speed); /// /// // By taking ownership of the original `Box<T>` though /// // we are obligated to put it together later to be destroyed. /// unsafe { /// drop(Box::from_raw(my_speed)); /// } /// ``` /// /// Note that here the call to `drop` is for clarity - it indicates /// that we are done with the given value and it should be destroyed. /// /// ## 3. Get it from C. /// /// ``` /// # #![feature(libc)] /// extern crate libc; /// /// use std::mem; /// /// fn main() { /// unsafe { /// let my_num: *mut i32 = libc::malloc(mem::size_of::<i32>() as libc::size_t) as *mut i32; /// if my_num.is_null() { /// panic!("failed to allocate memory"); /// } /// libc::free(my_num as *mut libc::c_void); /// } /// } /// ``` /// /// Usually you wouldn't literally use `malloc` and `free` from Rust, /// but C APIs hand out a lot of pointers generally, so are a common source /// of raw pointers in Rust. /// /// *[See also the `std::ptr` module](ptr/index.html).* /// mod prim_pointer { } #[doc(primitive = "array")] // /// A fixed-size array, denoted `[T; N]`, for the element type, `T`, and the /// non-negative compile time constant size, `N`. /// /// Arrays values are created either with an explicit expression that lists /// each element: `[x, y, z]` or a repeat expression: `[x; N]`. The repeat /// expression requires that the element type is `Copy`. /// /// The type `[T; N]` is `Copy` if `T: Copy`. /// /// Arrays of sizes from 0 to 32 (inclusive) implement the following traits if /// the element type allows it: /// /// - `Clone` (only if `T: Copy`) /// - `Debug` /// - `IntoIterator` (implemented for `&[T; N]` and `&mut [T; N]`) /// - `PartialEq`, `PartialOrd`, `Ord`, `Eq` /// - `Hash` /// - `AsRef`, `AsMut` /// - `Borrow`, `BorrowMut` /// - `Default` /// /// Arrays coerce to [slices (`[T]`)][slice], so their methods can be called on /// arrays. /// /// [slice]: primitive.slice.html /// /// Rust does not currently support generics over the size of an array type. /// /// # Examples /// /// ``` /// let mut array: [i32; 3] = [0; 3]; /// /// array[1] = 1; /// array[2] = 2; /// /// assert_eq!([1, 2], &array[1..]); /// /// // This loop prints: 0 1 2 /// for x in &array { /// print!("{} ", x); /// } /// /// ``` /// mod prim_array { } #[doc(primitive = "slice")] // /// A dynamically-sized view into a contiguous sequence, `[T]`. /// /// Slices are a view into a block of memory represented as a pointer and a /// length. /// /// ``` /// // slicing a Vec /// let vec = vec![1, 2, 3]; /// let int_slice = &vec[..]; /// // coercing an array to a slice /// let str_slice: &[&str] = &["one", "two", "three"]; /// ``` /// /// Slices are either mutable or shared. The shared slice type is `&[T]`, /// while the mutable slice type is `&mut [T]`, where `T` represents the element /// type. For example, you can mutate the block of memory that a mutable slice /// points to: /// /// ``` /// let x = &mut [1, 2, 3]; /// x[1] = 7; /// assert_eq!(x, &[1, 7, 3]); /// ``` /// /// *[See also the `std::slice` module](slice/index.html).* /// mod prim_slice { } #[doc(primitive = "str")] // /// String slices. /// /// The `str` type, also called a 'string slice', is the most primitive string /// type. It is usually seen in its borrowed form, `&str`. It is also the type /// of string literals, `&'static str`. /// /// Strings slices are always valid UTF-8. /// /// This documentation describes a number of methods and trait implementations /// on the `str` type. For technical reasons, there is additional, separate /// documentation in [the `std::str` module](str/index.html) as well. /// /// # Examples /// /// String literals are string slices: /// /// ``` /// let hello = "Hello, world!"; /// /// // with an explicit type annotation /// let hello: &'static str = "Hello, world!"; /// ``` /// /// They are `'static` because they're stored directly in the final binary, and /// so will be valid for the `'static` duration. /// /// # Representation /// /// A `&str` is made up of two components: a pointer to some bytes, and a /// length. You can look at these with the [`.as_ptr()`] and [`len()`] methods: /// /// ``` /// use std::slice; /// use std::str; /// /// let story = "Once upon a time..."; /// /// let ptr = story.as_ptr(); /// let len = story.len(); /// /// // story has nineteen bytes /// assert_eq!(19, len); /// /// // We can re-build a str out of ptr and len. This is all unsafe becuase /// // we are responsible for making sure the two components are valid: /// let s = unsafe { /// // First, we build a &[u8]... /// let slice = slice::from_raw_parts(ptr, len); /// /// // ... and then convert that slice into a string slice /// str::from_utf8(slice) /// }; /// /// assert_eq!(s, Ok(story)); /// ``` /// /// [`.as_ptr()`]: #method.as_ptr /// [`len()`]: #method.len mod prim_str { } #[doc(primitive = "tuple")] // /// A finite heterogeneous sequence, `(T, U, ..)`. /// /// To access the _N_-th element of a tuple one can use `N` itself /// as a field of the tuple. /// /// Indexing starts from zero, so `0` returns first value, `1` /// returns second value, and so on. In general, a tuple with _S_ /// elements provides aforementioned fields from `0` to `S-1`. /// /// If every type inside a tuple implements one of the following /// traits, then a tuple itself also implements it. /// /// * `Clone` /// * `PartialEq` /// * `Eq` /// * `PartialOrd` /// * `Ord` /// * `Debug` /// * `Default` /// * `Hash` /// /// # Examples /// /// Accessing elements of a tuple at specified indices: /// /// ``` /// let x = ("colorless", "green", "ideas", "sleep", "furiously"); /// assert_eq!(x.3, "sleep"); /// /// let v = (3, 3); /// let u = (1, -5); /// assert_eq!(v.0 * u.0 + v.1 * u.1, -12); /// ``` /// /// Using traits implemented for tuples: /// /// ``` /// let a = (1, 2); /// let b = (3, 4); /// assert!(a != b); /// /// let c = b.clone(); /// assert!(b == c); /// /// let d : (u32, f32) = Default::default(); /// assert_eq!(d, (0, 0.0f32)); /// ``` /// mod prim_tuple { } #[doc(primitive = "f32")] /// The 32-bit floating point type. /// /// *[See also the `std::f32` module](f32/index.html).* /// mod prim_f32 { } #[doc(primitive = "f64")] // /// The 64-bit floating point type. /// /// *[See also the `std::f64` module](f64/index.html).* /// mod prim_f64 { } #[doc(primitive = "i8")] // /// The 8-bit signed integer type. /// /// *[See also the `std::i8` module](i8/index.html).* /// mod prim_i8 { } #[doc(primitive = "i16")] // /// The 16-bit signed integer type. /// /// *[See also the `std::i16` module](i16/index.html).* /// mod prim_i16 { } #[doc(primitive = "i32")] // /// The 32-bit signed integer type. /// /// *[See also the `std::i32` module](i32/index.html).* /// mod prim_i32 { } #[doc(primitive = "i64")] // /// The 64-bit signed integer type. /// /// *[See also the `std::i64` module](i64/index.html).* /// mod prim_i64 { } #[doc(primitive = "u8")] // /// The 8-bit unsigned integer type. /// /// *[See also the `std::u8` module](u8/index.html).* /// mod prim_u8 { } #[doc(primitive = "u16")] // /// The 16-bit unsigned integer type. /// /// *[See also the `std::u16` module](u16/index.html).* /// mod prim_u16 { } #[doc(primitive = "u32")] // /// The 32-bit unsigned integer type. /// /// *[See also the `std::u32` module](u32/index.html).* /// mod prim_u32 { } #[doc(primitive = "u64")] // /// The 64-bit unsigned integer type. /// /// *[See also the `std::u64` module](u64/index.html).* /// mod prim_u64 { } #[doc(primitive = "isize")] // /// The pointer-sized signed integer type. /// /// *[See also the `std::isize` module](isize/index.html).* /// mod prim_isize { } #[doc(primitive = "usize")] // /// The pointer-sized unsigned integer type. /// /// *[See also the `std::usize` module](usize/index.html).* /// mod prim_usize { }