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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
54a0048b 11//! The Rust Prelude.
1a4d82fc 12//!
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13//! Rust comes with a variety of things in its standard library. However, if
14//! you had to manually import every single thing that you used, it would be
15//! very verbose. But importing a lot of things that a program never uses isn't
16//! good either. A balance needs to be struck.
17//!
18//! The *prelude* is the list of things that Rust automatically imports into
19//! every Rust program. It's kept as small as possible, and is focused on
7453a54e 20//! things, particularly traits, which are used in almost every single Rust
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21//! program.
22//!
23//! On a technical level, Rust inserts
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24//!
25//! ```ignore
26//! extern crate std;
27//! ```
28//!
92a42be0 29//! into the crate root of every crate, and
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30//!
31//! ```ignore
32//! use std::prelude::v1::*;
33//! ```
34//!
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35//! into every module.
36//!
37//! # Other preludes
38//!
39//! Preludes can be seen as a pattern to make using multiple types more
40//! convenient. As such, you'll find other preludes in the standard library,
41//! such as [`std::io::prelude`]. Various libraries in the Rust ecosystem may
42//! also define their own preludes.
43//!
44//! [`std::io::prelude`]: ../io/prelude/index.html
45//!
9cc50fc6 46//! The difference between 'the prelude' and these other preludes is that they
92a42be0 47//! are not automatically `use`'d, and must be imported manually. This is still
7453a54e 48//! easier than importing all of their constituent components.
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49//!
50//! # Prelude contents
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51//!
52//! The current version of the prelude (version 1) lives in
92a42be0 53//! [`std::prelude::v1`], and reexports the following.
c1a9b12d 54//!
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55//! * [`std::marker`]::{[`Copy`], [`Send`], [`Sized`], [`Sync`]}. The marker
56//! traits indicate fundamental properties of types.
57//! * [`std::ops`]::{[`Drop`], [`Fn`], [`FnMut`], [`FnOnce`]}. Various
7453a54e 58//! operations for both destructors and overloading `()`.
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59//! * [`std::mem`]::[`drop`], a convenience function for explicitly dropping a
60//! value.
61//! * [`std::boxed`]::[`Box`], a way to allocate values on the heap.
62//! * [`std::borrow`]::[`ToOwned`], The conversion trait that defines
63//! [`to_owned()`], the generic method for creating an owned type from a
64//! borrowed type.
65//! * [`std::clone`]::[`Clone`], the ubiquitous trait that defines [`clone()`],
66//! the method for producing a copy of a value.
67//! * [`std::cmp`]::{[`PartialEq`], [`PartialOrd`], [`Eq`], [`Ord`] }. The
68//! comparison traits, which implement the comparison operators and are often
69//! seen in trait bounds.
70//! * [`std::convert`]::{[`AsRef`], [`AsMut`], [`Into`], [`From`]}. Generic
71//! conversions, used by savvy API authors to create overloaded methods.
72//! * [`std::default`]::[`Default`], types that have default values.
73//! * [`std::iter`]::{[`Iterator`], [`Extend`], [`IntoIterator`],
74//! [`DoubleEndedIterator`], [`ExactSizeIterator`]}. Iterators of various
75//! kinds.
76//! * [`std::option`]::[`Option`]::{`self`, `Some`, `None`}. A type which
77//! expresses the presence or absence of a value. This type is so commonly
78//! used, its variants are also exported.
79//! * [`std::result`]::[`Result`]::{`self`, `Ok`, `Err`}. A type for functions
80//! that may succeed or fail. Like [`Option`], its variants are exported as
81//! well.
82//! * [`std::slice`]::[`SliceConcatExt`], a trait that exists for technical
83//! reasons, but shouldn't have to exist. It provides a few useful methods on
84//! slices.
85//! * [`std::string`]::{[`String`], [`ToString`]}, heap allocated strings.
86//! * [`std::vec`]::[`Vec`](../vec/struct.Vec.html), a growable, heap-allocated
87//! vector.
c1a9b12d 88//!
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89//! [`AsMut`]: ../convert/trait.AsMut.html
90//! [`AsRef`]: ../convert/trait.AsRef.html
91//! [`Box`]: ../boxed/struct.Box.html
92//! [`Clone`]: ../clone/trait.Clone.html
93//! [`Copy`]: ../marker/trait.Copy.html
94//! [`Default`]: ../default/trait.Default.html
95//! [`DoubleEndedIterator`]: ../iter/trait.DoubleEndedIterator.html
96//! [`Drop`]: ../ops/trait.Drop.html
97//! [`Eq`]: ../cmp/trait.Eq.html
98//! [`ExactSizeIterator`]: ../iter/trait.ExactSizeIterator.html
99//! [`Extend`]: ../iter/trait.Extend.html
100//! [`FnMut`]: ../ops/trait.FnMut.html
101//! [`FnOnce`]: ../ops/trait.FnOnce.html
102//! [`Fn`]: ../ops/trait.Fn.html
103//! [`From`]: ../convert/trait.From.html
104//! [`IntoIterator`]: ../iter/trait.IntoIterator.html
105//! [`Into`]: ../convert/trait.Into.html
106//! [`Iterator`]: ../iter/trait.Iterator.html
107//! [`Option`]: ../option/enum.Option.html
108//! [`Ord`]: ../cmp/trait.Ord.html
109//! [`PartialEq`]: ../cmp/trait.PartialEq.html
110//! [`PartialOrd`]: ../cmp/trait.PartialOrd.html
111//! [`Result`]: ../result/enum.Result.html
112//! [`Send`]: ../marker/trait.Send.html
113//! [`Sized`]: ../marker/trait.Sized.html
114//! [`SliceConcatExt`]: ../slice/trait.SliceConcatExt.html
115//! [`String`]: ../string/struct.String.html
116//! [`Sync`]: ../marker/trait.Sync.html
117//! [`ToOwned`]: ../borrow/trait.ToOwned.html
118//! [`ToString`]: ../string/trait.ToString.html
119//! [`Vec`]: ../vec/struct.Vec.html
120//! [`clone()`]: ../clone/trait.Clone.html#tymethod.clone
121//! [`drop`]: ../mem/fn.drop.html
122//! [`std::borrow`]: ../borrow/index.html
123//! [`std::boxed`]: ../boxed/index.html
124//! [`std::clone`]: ../clone/index.html
125//! [`std::cmp`]: ../cmp/index.html
126//! [`std::convert`]: ../convert/index.html
127//! [`std::default`]: ../default/index.html
128//! [`std::iter`]: ../iter/index.html
129//! [`std::marker`]: ../marker/index.html
130//! [`std::mem`]: ../mem/index.html
131//! [`std::ops`]: ../ops/index.html
132//! [`std::option`]: ../option/index.html
133//! [`std::prelude::v1`]: v1/index.html
134//! [`std::result`]: ../result/index.html
135//! [`std::slice`]: ../slice/index.html
136//! [`std::string`]: ../string/index.html
137//! [`std::vec`]: ../vec/index.html
138//! [`to_owned()`]: ../borrow/trait.ToOwned.html#tymethod.to_owned
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139//! [book-closures]: ../../book/closures.html
140//! [book-dtor]: ../../book/drop.html
c1a9b12d 141//! [book-enums]: ../../book/enums.html
92a42be0 142//! [book-iter]: ../../book/iterators.html
1a4d82fc 143
85aaf69f 144#![stable(feature = "rust1", since = "1.0.0")]
1a4d82fc 145
1a4d82fc 146pub mod v1;