Rust war lange Zeit ausschließlich als Systemprogrammiersprache positioniert. Versuche, Rust für Anwendungen auf hoher Ebene zu verwenden, verursachten in einem großen Teil der Community häufig ein Grinsen: Warum sollte das Tool in einer Qualität verwendet werden, für die es nicht entwickelt wurde? Was nützt es, sich mit Typen und Leihprüfern zu beschäftigen, wenn Sie Python und Java mit Garbage Collection haben? Aber ein anderer Teil der Community hat das Potenzial von Rust immer genau als Anwendungssprache gesehen und es sogar als zweckmäßig empfunden, es für Rapid Prototyping zu verwenden - hauptsächlich aufgrund seiner Funktionen und nicht im Widerspruch zu diesen.
, Rust , . , , Rust . , , :
Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.
Rust — segfault' .
:
A language empowering everyone to build reliable and efficient software.
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unsafe-
, Rust :
let a: Vec<_> = [1, 2, 3].iter().filter(|&i| i % 2 != 0).map(|i| i * 2).collect();
, — filter map, Vec. — ( JavaScript). , Iter, .iter():
pub struct Iter<'a, T: 'a> {
ptr: NonNull<T>,
end: *const T,
_marker: marker::PhantomData<&'a T>,
}
impl<'a, T> Iterator for Iter<'a, T> {
type Item = &'a T;
#[inline]
fn next(&mut self) -> Option<&'a T> {
unsafe {
assume(!self.ptr.as_ptr().is_null());
if mem::size_of::<T>() != 0 {
assume(!self.end.is_null());
}
if is_empty!(self) {
None
} else {
Some(next_unchecked!(self))
}
}
}
...
}
std::slice::Iter
, Iter : ptr end ( 2 3). - , — - ( NonNull , ), , borrow checker'. 'a (1) "" PhantomData<&'a T> (4). , . , : , , , , . . , ( unsafe-, 5), API safe Rust.
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, , Rust — . . : "" Rust , API.
, unsafe, Rust — , . Rust : , , std unsafe-? unsafe, safe. Rust , , . , Rust - .
, for Python:
for x in range(5):
print(x)
Rust:
for x in 0..5 {
println!("{}", x);
}
, ? for Rust — . for:
match IntoIterator::into_iter(0..5) {
mut iter => loop {
let next;
match iter.next() {
Some(val) => next = val,
None => break,
};
let x = next;
let () = {
println!("{}", x);
};
},
}
for Loops and IntoIterator
, 0..5 for , IntoIterator, x — , let. , for, :
macro_rules! foret {
($x:pat in $exp:expr => $body:expr) => {{
let mut result = None;
match IntoIterator::into_iter($exp) {
mut iter => loop {
let next;
match iter.next() {
Some(val) => next = val,
None => break result,
};
let $x = next;
result = Some($body);
},
}
}}
}
let result = foret!(x in 0..5 => {
println!("{}", x);
x
});
assert_eq!(result, Some(4));
Rust — — - . foret. , : expr ( Rust ) , =>. , , .
, , . , Rust — " ", Rust. Rust — , . , , . actix-web:
use std::io;
use actix_web::{get, web, App, HttpServer, Responder};
#[get("/{id}/{name}/index.html")]
async fn index(info: web::Path<(u32, String)>) -> impl Responder {
format!("Hello {}! id:{}", info.1, info.0)
}
#[actix_rt::main]
async fn main() -> io::Result<()> {
HttpServer::new(|| App::new().service(index))
.bind("127.0.0.1:8080")?
.run()
.await
}
#[get(..)] #[actix_rt::main] — , , , . :
use std::io;
use actix_web::{get, web, App, HttpServer, Responder};
#[allow(non_camel_case_types, missing_docs)]
pub struct index;
impl actix_web::dev::HttpServiceFactory for index {
fn register(self, __config: &mut actix_web::dev::AppService) {
async fn index(info: web::Path<(u32, String)>) -> impl Responder {
{
let res = ::alloc::fmt::format(::core::fmt::Arguments::new_v1(
&["Hello ", "! id:"],
&match (&info.1, &info.0) {
(arg0, arg1) => [
::core::fmt::ArgumentV1::new(arg0, ::core::fmt::Display::fmt),
::core::fmt::ArgumentV1::new(arg1, ::core::fmt::Display::fmt),
],
},
));
res
}
}
let __resource = actix_web::Resource::new("/{id}/{name}/index.html")
.name("index")
.guard(actix_web::guard::Get())
.to(index);
actix_web::dev::HttpServiceFactory::register(__resource, __config)
}
}
fn main() -> io::Result<()> {
actix_rt::System::new("main").block_on(async move {
{
HttpServer::new(|| App::new().service(index))
.bind("127.0.0.1:8080")?
.run()
.await
}
})
}
index HttpServiceFactory, main .
— html yew, Rust- html- DSL Web-:
impl Component for Model {
...
fn view(&self) -> Html {
html! {
<div>
<button onclick = self.link.callback(|_| Msg::Click)>{ "Click" }</button>
</div>
}
}
}
, , html- , Rust-. JSX, JavaScript. Rust , — .
. , , , Rust . , , . Rust - , .
( Python), "" , , Rust "", "" .
, , , . , , :
sleep(5);
, Rust:
use std::{thread, time::Duration};
thread::sleep(Duration::from_secs(5));
, - ? , .
, , Rust : , , , , . ( , Duration, - , repr.)
— "" , , . Rust :
struct Celsius(f64);
struct Fahrenheit(f64);
let a = Celsius(5.);
let b = Fahrenheit(5.);
, a b , . " " (New type), . ( " " .)
" ", Rust, . , , - . , , , .
, , . :
fn min<T: PartialOrd>(a: T, b: T) -> T {
if b < a { b } else { a }
}
, T, . , , (traits), . . , , , . , . :
pub struct HashMap<K, V, S = RandomState> {
...
}
impl<K, V, S> HashMap<K, V, S>
where
K: Eq + Hash,
S: BuildHasher,
{
...
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.base.get(k)
}
...
}
std::collections::HashMap
get -, V, K, Q, ( K: Borrow<Q>). ? , , , (K = String) , get (&Q = &K = &String), , , (&Q = &str), Borrow. : , — get .
- . . , :
pub struct UserId(u32);
, UserId , , UserId . ( , .)
UserId -, , , UserId - , . u32! , , , , , , - , . , Borrow:
impl Borrow<u32> for UserId {
fn borrow(&self) -> &u32 {
&self.0
}
}
get. Q — Q: ?Sized. , Q ( ). , . , .
, , , , , . :
pub trait AsMapKey: ?Sized + Hash + Eq {}
impl<T: ?Sized + Hash + Eq> AsMapKey for T {}
, , . .
Rust - enum, , , , . — (), .
— Value serde_json, JSON-:
pub enum Value {
Null,
Bool(bool),
Number(Number),
String(String),
Array(Vec<Value>),
Object(Map<String, Value>),
}
serde_json::Value
. , .
, enum Rust , — ! — , . .
— . null. , null — , , . null , null , ( , ).
Rust:
pub enum Option<T> {
None,
Some(T),
}
std::option::Option
null . , Option , , . " ", , null, Option : Option::None null . Option .
, " ".
Rust . . , , , , . , — . , Drop .
Java, , try-with-resources . , try-with-resources . Cleaner , — ( Java " finalize()? ").
Rust , , .
, -: , (), . , , :
mod machine {
pub struct StateA(String);
pub struct StateB(String);
pub struct StateC(String);
pub fn start(data: impl Into<String>) -> StateA {
StateA(data.into())
}
impl StateA {
pub fn step(self) -> StateB {
StateB(self.0)
}
}
impl StateB {
pub fn step(self) -> StateC {
StateC(self.0)
}
}
}
let a = machine::start("Hello");
let c = a.step().step();
machine StateC , StateA, step , StateB. step .
, . Rust .
, . , (view), . .
, String, Deref, : &String &str. , AsRef, as_ref &[u8], - &OsStr &Path. OsStr String, OsString ( ). Path OsStr :
pub struct Path {
inner: OsStr,
}
impl Path {
pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &Path {
unsafe { &*(s.as_ref() as *const OsStr as *const Path) }
}
...
}
std::path::Path source
, ? , Path::new , &OsStr, &OsStr &Path , , ( OsStr Path). , Path::new , . String Path , String OsStr, , Path.
-, Rust . , , . DTO-, diesel. Rust — , , -, , .
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