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1 | // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
bd371182 | 11 | //! The Rust Prelude |
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12 | //! |
13 | //! Because `std` is required by most serious Rust software, it is | |
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14 | //! imported at the topmost level of every crate by default, as if |
15 | //! each crate contains the following: | |
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16 | //! |
17 | //! ```ignore | |
18 | //! extern crate std; | |
19 | //! ``` | |
20 | //! | |
21 | //! This means that the contents of std can be accessed from any context | |
bd371182 | 22 | //! with the `std::` path prefix, as in `use std::vec`, `use std::thread::spawn`, |
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23 | //! etc. |
24 | //! | |
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25 | //! Additionally, `std` contains a versioned *prelude* that reexports many of the |
26 | //! most common traits, types, and functions. *The contents of the prelude are | |
27 | //! imported into every module by default*. Implicitly, all modules behave as if | |
28 | //! they contained the following [`use` statement][book-use]: | |
29 | //! | |
30 | //! [book-use]: ../../book/crates-and-modules.html#importing-modules-with-use | |
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31 | //! |
32 | //! ```ignore | |
33 | //! use std::prelude::v1::*; | |
34 | //! ``` | |
35 | //! | |
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36 | //! The prelude is primarily concerned with exporting *traits* that |
37 | //! are so pervasive that they would be onerous to import for every use, | |
38 | //! particularly those that are commonly mentioned in [generic type | |
39 | //! bounds][book-traits]. | |
40 | //! | |
41 | //! The current version of the prelude (version 1) lives in | |
42 | //! [`std::prelude::v1`](v1/index.html), and reexports the following. | |
43 | //! | |
44 | //! * `std::marker::`{ | |
45 | //! [`Copy`](../marker/trait.Copy.html), | |
46 | //! [`Send`](../marker/trait.Send.html), | |
47 | //! [`Sized`](../marker/trait.Sized.html), | |
48 | //! [`Sync`](../marker/trait.Sync.html) | |
49 | //! }. | |
50 | //! The marker traits indicate fundamental properties of types. | |
51 | //! * `std::ops::`{ | |
52 | //! [`Drop`](../ops/trait.Drop.html), | |
53 | //! [`Fn`](../ops/trait.Fn.html), | |
54 | //! [`FnMut`](../ops/trait.FnMut.html), | |
55 | //! [`FnOnce`](../ops/trait.FnOnce.html) | |
56 | //! }. | |
57 | //! The [destructor][book-dtor] trait and the | |
58 | //! [closure][book-closures] traits, reexported from the same | |
59 | //! [module that also defines overloaded | |
60 | //! operators](../ops/index.html). | |
61 | //! * `std::mem::`[`drop`](../mem/fn.drop.html). | |
62 | //! A convenience function for explicitly dropping a value. | |
63 | //! * `std::boxed::`[`Box`](../boxed/struct.Box.html). | |
64 | //! The owned heap pointer. | |
65 | //! * `std::borrow::`[`ToOwned`](../borrow/trait.ToOwned.html). | |
66 | //! The conversion trait that defines `to_owned`, the generic method | |
67 | //! for creating an owned type from a borrowed type. | |
68 | //! * `std::clone::`[`Clone`](../clone/trait.Clone.html). | |
69 | //! The ubiquitous trait that defines `clone`, the method for | |
70 | //! producing copies of values that are consider expensive to copy. | |
71 | //! * `std::cmp::`{ | |
72 | //! [`PartialEq`](../cmp/trait.PartialEq.html), | |
73 | //! [`PartialOrd`](../cmp/trait.PartialOrd.html), | |
74 | //! [`Eq`](../cmp/trait.Eq.html), | |
75 | //! [`Ord`](../cmp/trait.Ord.html) | |
76 | //! }. | |
b039eaaf | 77 | //! The comparison traits, which implement the comparison operators |
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78 | //! and are often seen in trait bounds. |
79 | //! * `std::convert::`{ | |
80 | //! [`AsRef`](../convert/trait.AsRef.html), | |
81 | //! [`AsMut`](../convert/trait.AsMut.html), | |
82 | //! [`Into`](../convert/trait.Into.html), | |
83 | //! [`From`](../convert/trait.From.html) | |
84 | //! }. | |
85 | //! Generic conversions, used by savvy API authors to create | |
86 | //! overloaded methods. | |
b039eaaf | 87 | //! * `std::default::`[`Default`](../default/trait.Default.html). |
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88 | //! Types that have default values. |
89 | //! * `std::iter::`{ | |
90 | //! [`Iterator`](../iter/trait.Iterator.html), | |
91 | //! [`Extend`](../iter/trait.Extend.html), | |
92 | //! [`IntoIterator`](../iter/trait.IntoIterator.html), | |
93 | //! [`DoubleEndedIterator`](../iter/trait.DoubleEndedIterator.html), | |
94 | //! [`ExactSizeIterator`](../iter/trait.ExactSizeIterator.html) | |
95 | //! }. | |
96 | //! [Iterators][book-iter]. | |
97 | //! * `std::option::Option::`{ | |
98 | //! [`self`](../option/enum.Option.html), | |
99 | //! [`Some`](../option/enum.Option.html), | |
100 | //! [`None`](../option/enum.Option.html) | |
101 | //! }. | |
102 | //! The ubiquitous `Option` type and its two [variants][book-enums], | |
103 | //! `Some` and `None`. | |
104 | //! * `std::result::Result::`{ | |
105 | //! [`self`](../result/enum.Result.html), | |
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106 | //! [`Ok`](../result/enum.Result.html), |
107 | //! [`Err`](../result/enum.Result.html) | |
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108 | //! }. |
109 | //! The ubiquitous `Result` type and its two [variants][book-enums], | |
110 | //! `Ok` and `Err`. | |
111 | //! * `std::slice::`[`SliceConcatExt`](../slice/trait.SliceConcatExt.html). | |
112 | //! An unstable extension to slices that shouldn't have to exist. | |
113 | //! * `std::string::`{ | |
114 | //! [`String`](../string/struct.String.html), | |
115 | //! [`ToString`](../string/trait.ToString.html) | |
116 | //! }. | |
117 | //! Heap allocated strings. | |
118 | //! * `std::vec::`[`Vec`](../vec/struct.Vec.html). | |
119 | //! Heap allocated vectors. | |
120 | //! | |
121 | //! [book-traits]: ../../book/traits.html | |
122 | //! [book-closures]: ../../book/closures.html | |
123 | //! [book-dtor]: ../../book/drop.html | |
124 | //! [book-iter]: ../../book/iterators.html | |
125 | //! [book-enums]: ../../book/enums.html | |
1a4d82fc | 126 | |
85aaf69f | 127 | #![stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 128 | |
1a4d82fc | 129 | pub mod v1; |