Rust (programming language): Difference between revisions

Revision as of 11:41, 26 June 2025

Revision as of 12:14, 26 June 2025

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'''Rust''' is a [[General-purpose programming language|general-purpose]] [[programming language]] emphasizing [[Computer performance|performance]], [[type safety]], and [[Concurrency (computer science)|concurrency]]. It enforces [[memory safety]], meaning that all [[Reference (computer science)|references]] point to valid memory. It does so without a conventional [[Garbage collection (computer science)|garbage collector]]; instead, memory safety errors and [[data race]]s are prevented by the "borrow checker", which tracks the [[object lifetime]] of references [[Compiler|at compile time]].

Rust supports multiple [[programming paradigm]]s. It was influenced by ideas from [[functional programming]], including [[Immutable object|immutability]], [[higher-order function]]s, [[algebraic data type]]s, and [[pattern matching]]. It also supports [[object-oriented programming]] via structs, [[UnionEnumerated type|enums]], traits, and methods.

Software developer Graydon Hoare created Rust as a personal project while working at [[Mozilla]] Research in 2006. Mozilla officially sponsored the project in 2009. The first stable release of Rust, Rust 1.0, was published in May 2015. Following a large layoff of Mozilla employees in August 2020, multiple other companies joined Mozilla in sponsoring Rust through the creation of the [[#Rust Foundation|Rust Foundation]] in February 2021. In December 2022, Rust became the first language other than [[C (programming language)|C]] and [[Assembly language|assembly]] to be supported in the development of the [[Linux kernel]].

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==== Standard library ====

The Rust [[standard library]] defines and implements many widely used custom data types, including core data structures such as {{code|Vec}}, {{code|Option}}, and {{code|HashMap}}, as well as [[smart pointer]] types. Rust also provides a way to exclude most of the standard library using the attribute {{rust|#![no_std]}}; this enables applications, such as embedded devices, which want to remove dependency code or provide their own core data structures. Internally, the standard library is divided into three parts, {{code|core}}, {{code|alloc}}, and {{code|std}}, where {{code|std}} and {{Code|alloc}} are excluded by {{rust|#![no_std]}}.{{sfn|Gjengset|2021|pp=213-215}}

Rust uses [[Option type|<code>Option</code>]] valuesto aredefine handledoptional usingvalues, [[syntacticwhich sugar]],can suchbe asmatched theusing <code>if let</code> construction,or <code>match</code> to access the inner value (in this case, a string):{{sfn|McNamaraKlabnik|2021Nichols|2023|pp=108-110,113-114,116-117}}

<syntaxhighlight lang="rust">

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=== Pointers ===

RustThe also<code>&</code> supportsand {{rust|&mut}} reference types are guaranteed to not be null and points to valid memory.{{sfn|Gjengset|2021|p=155-156}} The raw pointer types <code>{{rust|*const</code>}} and <code>{{rust|*mut</code>}} opts out of the safety guarantees, whichthus they may be null and invalid; however, it is impossible to dereference them unless the code is explicitly declared unsafe through the use of an <code>{{rust|unsafe</code>}} block.{{sfn|Klabnik|Nichols|2023|pp=421-423}} Unlike dereferencing, the creation of raw pointers is allowed inside of safe Rust code.{{sfn|Klabnik|Nichols|2019|pp=418–427}}

{| class="wikitable"

|+Summary of Rust's [[Pointer (computer programming)|pointer]] and [[Reference (computer science)|reference]] primitive types

!Type

!Description

!Examples

|-

|{{plainlist|

* {{Rust|&T}}

* {{Rust|&mut T}}

}}

|[[Reference (computer science)|References]] (immutable and mutable)

|{{plainlist|

* {{Rust|let x_ref: &T {{=}} {{not a typo|&x;}}}}

* {{Rust|let x_ref: &mut T {{=}} &mut x;}}

}}

|-

|{{plainlist|

* {{Rust|Option<&T>}}

* {{Rust|Option<&mut T>}}

}}

|{{plainlist|

* Option wrapped reference

* Possibly null reference

}}

|{{plainlist|

* {{Rust|None}}

* {{Rust|let x_ref: Option<&T> {{=}} Some(&x);}}

* {{Rust|let x_ref: Option<&mut T> {{=}} Some(&mut x);}}

}}

|-

|{{Plain list|* {{Rust|Box<T>}}

* {{Rust|Option<Box<T>>}}}}

|A pointer to heap-allocated value

(or possibly null pointer if wrapped in option)<ref name="std::boxed"/>

|{{Plain list|* {{Rust|let boxed: Box<u8> {{=}} Box::new(0);}}

* {{Rust|let boxed: Option<Box<String>> {{=}} Some(Box::new("Hello World"));}}}}

|-

|{{Plainlist|

* {{Rust|*const T}}

* {{Rust|*mut T}}

}}

|{{Plainlist|

* Raw pointers (immutable and mutable)

* Possibly [[Null pointer|null]]; {{Rust|unsafe}} to [[dereference]]

}}

|{{Plainlist|

* {{Rust|let x_ptr: *const T {{=}} &x as *const T;}}

* {{Rust|let x_ptr: *mut T {{=}} &mut x as *mut T;}}

}}

|}

To prevent the use of [[null pointer]]s and their [[Null pointer#Null dereferencing|dereferencing]], the basic <code>&</code> and <code>&mut</code> references are guaranteed to not be null. Rust instead uses <code>Option</code> for this purpose: <code>Some(T)</code> indicates that a value is present, and <code>None</code> is analogous to the null pointer.{{sfn|Klabnik|Nichols|2019|pp=101–104}} <code>Option</code> implements a "null pointer optimization", avoiding any spatial overhead for types that cannot have a null value (references or the <code>NonZero</code> types, for example).{{sfn|Gjengset|2021|p=145}}

Rust also supports raw pointer types <code>*const</code> and <code>*mut</code>, which may be null; however, it is impossible to dereference them unless the code is explicitly declared unsafe through the use of an <code>unsafe</code> block. Unlike dereferencing, the creation of raw pointers is allowed inside of safe Rust code.{{sfn|Klabnik|Nichols|2019|pp=418–427}}

=== Type conversion ===

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[[File:Cargo compiling.webm|thumb|right|Compiling a Rust program with Cargo]]

The Rust ecosystem includes its compiler, its [[#Standard library|standard library]], and additional components for software development. Component installation is typically managed by {{code|rustup}}, a Rust [[toolchain]] installer developed by the Rust project.{{sfn|Blandy|Orendorff|Tindall|2021|pp=6-8}}

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