1489 lines
37 KiB
Rust
1489 lines
37 KiB
Rust
use std::cell::RefCell;
|
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use std::hash::Hash;
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use std::ops::Deref;
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use std::rc::{Rc, Weak};
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use std::sync::{mpsc, Arc, Mutex};
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use std::time::Duration;
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use std::{collections::HashMap, fmt::Display, fs::File, io, io::ErrorKind, thread};
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fn main() {
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let mut s = String::from("Hello");
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s.push_str(", World!");
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println!("{}", s);
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let c: char = 'd';
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println!("{}", c);
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let x = 5;
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// cannot assign twice to immutable variable
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// x = x + 1;
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// 使用 let 重新定义 x，隐藏了之前 x 的值
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let x = x + 1;
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println!("The value of x is {}", x);
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let x = "test";
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println!("The value of x is {}", x);
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// 可变变量
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let mut x = 2;
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x = x * 3;
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// expected integer, found reference
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// x = "test";
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println!("The value of x is {}", x);
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// : 指定变量类型
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let mut y: i32 = 22;
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println!("The value of y is {}", y);
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y = 12;
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println!("The value of y is {}", y);
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// 可变引用
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let mut s = String::from("hello");
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let s1 = &mut s;
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// 在特定作用域中的特定数据有且只有一个可变引用
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// let s2 = &mut s;
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change(s1);
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println!("{}", s1);
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{
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let s2 = &mut s;
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println!("{}", s2);
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}
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// 多个不可变引用是可以的
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let r1 = &s;
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let r2 = &s;
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// 不能在拥有不可变引用的同时拥有可变引用
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// let r3 = &mut s;
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println!("{}, {}", r1, r2);
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// ---------------------------
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println!("----------------------------------------");
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let home = IpAddr::V4(127, 0, 0, 1);
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let loopback = IpAddr::V6(String::from("::1"));
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println!("{:?}, {:?}", home, loopback);
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let m = Message::Quit;
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m.call();
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let m = &Message::Move { x: 1, y: 2 };
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match m {
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Message::Move { x, y } => println!("x: {}, y: {}", x, y),
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_ => {}
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}
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m.call();
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let m = Message::Write(String::from("test"));
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m.call();
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let m = Message::ChangeColor(1, 2, 3);
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m.call();
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// ---------------------------
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println!("----------------------------------------");
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let my_str = String::from("hello world!");
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// let my_str = "hello world!";
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println!("{}, {}", my_str, first_words(&my_str[..]));
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println!("get first word: {}", first_words("hello world"));
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let rect = Rectangle {
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width: 21,
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height: 23,
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};
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println!(
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"The area of the rectangle is {} square pixels.",
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rect.area()
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);
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let rect1 = Rectangle {
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width: 30,
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height: 50,
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};
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let rect2 = Rectangle {
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width: 10,
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height: 40,
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};
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let rect3 = Rectangle {
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width: 60,
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height: 45,
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};
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println!("rect1 is {:#?}", rect1);
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println!("Can rect1 hold rect2? {}", rect1.can_hold(&rect2));
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println!("Can rect1 hold rect3? {}", rect1.can_hold(&rect3));
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let rece4 = Rectangle::square(8);
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println!(
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"The area of the rectangle is {} square pixels.",
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rece4.area()
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);
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// ---------------------------
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println!("-----------------vec-----------------------");
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let mut v = vec![100, 32, 57];
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for i in &mut v {
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*i += 50;
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}
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println!("{:?}", v);
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// let mut v=Vec::new();
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let v = vec![1, 2, 3, 4, 5, 6, 7, 8, 9];
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let f = v.get(100);
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println!("{:?}", f);
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let f = &v[0];
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println!("{}", f);
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// v.push(12);
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let d: Option<u32> = None;
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println!("{:?} {}", d, d.is_none());
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let s = Some("ddd");
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println!("{:#?}", s);
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let s: Option<u32> = Some(2);
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println!("{},{}", s.unwrap(), s.is_some());
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performance_group::clarinet_trio();
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performance_group::instrument::clarinet();
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let s1 = String::from("Hello");
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let s2 = String::from("World");
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// + == fn add(self, s: &str) -> String
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// 这个语句会获取 s1 的所有权，附加上从 s2 中拷贝的内容，并返回结果的所有权
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let s3 = s1 + &s2;
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let s = format!("{}-{}", s2, s3);
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println!("{}", s);
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let hello = "你好";
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println!("{}", hello.len()); // output: 6
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let s = &hello[0..3]; // output: 你
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println!("{}", s);
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for c in hello.chars() {
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println!("{}", c);
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}
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for b in hello.bytes() {
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println!("{}", b);
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}
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// ---------------------------
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println!("----------------------------------------");
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let mut scores = HashMap::new();
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scores.insert(String::from("Blue"), 10);
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scores.insert(String::from("Yellow"), 50);
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let team_name = String::from("Blue");
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let score = scores.get(&team_name);
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println!("{}", score.unwrap());
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for (k, v) in scores.iter() {
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println!("{}, {}", k, v)
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}
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scores.entry(String::from("Yellow")).or_insert(50);
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let black = scores.entry(String::from("black")).or_insert(50);
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// cannot borrow `scores` as immutable because it is also borrowed as mutable
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// println!("{:?}, {}", scores, black);
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println!("{}", black);
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println!("{:#?}", scores);
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let text = "hello world wonderful world";
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let mut map = HashMap::new();
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for word in text.split_whitespace() {
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let count = map.entry(word).or_insert(0);
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*count += 1;
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}
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println!("{:?}", map);
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// ---------------------------
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println!("----------------------------------------");
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let f = match File::open("hello.txt") {
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Ok(file) => file,
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Err(error) => match error.kind() {
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ErrorKind::NotFound => match File::create("hello.txt") {
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Ok(file) => file,
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Err(e) => panic!("Tried to create file but there was a problem: {:?}", e),
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},
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ot_err => panic!("There was a problem opening the file: {:?}", ot_err),
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},
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};
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println!("{:?}", f.metadata());
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match read_username_from_file() {
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Ok(st) => println!("{}", st),
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Err(err) => panic!("There was a problem read string: {:?}", err),
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};
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let h: std::net::IpAddr = "127.0.0.1".parse().unwrap();
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let s: String = "127.0.0.1".parse().unwrap();
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println!("{:?}, {}", h, s);
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let v = ["d", "fd"];
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println!("{:?}", v);
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let v = vec!["d", "fd"];
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println!("{:?}", v);
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// ---------------------------
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println!("----------------------------------------");
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let t = Tweet {
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username: String::from("horse_ebooks"),
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content: String::from("of course, as you probably already know, people"),
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reply: false,
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retweet: false,
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};
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let t1 = returns_summarizable();
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println!("{}", notify(&t, &t1));
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let number_list = vec![34, 50, 25, 100, 65];
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let result = largest(&number_list);
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println!("The largest number is {}", result);
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let char_list = vec!['y', 'm', 'a', 'q'];
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let result = largest(&char_list);
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println!("The largest char is {}", result);
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// ---------------------------
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println!("----------------------------------------");
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let p = Pair::new(String::from("t"), String::from("s"));
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p.cmp_display();
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let p = Pair::new(
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Rectangle {
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width: 2,
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height: 3,
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},
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Rectangle {
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width: 4,
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height: 9,
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},
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);
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println!("{:?}", p);
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// no method named `cmp_display` found for type `Pair<Rectangle>` in the current scope
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// p.cmp_display();
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// ---------------------------
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println!("----------------------------------------");
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let s1 = String::from("abcd");
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let r;
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{
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let s2 = String::from("qw");
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r = longest(s1.as_str(), s2.as_ref());
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println!("The longest string is {}", r);
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}
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// `s2` does not live long enough
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// println!("The longest string is {}", r);
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let closure = |x: u32| -> u32 { x + 2 };
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// let closure = |x| x + 2;
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println!("closure: {}", closure(3));
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let mut s = String::from("hello");
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let d = change;
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d(&mut s);
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println!("{}", s);
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generate_workout(10, 3);
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// ---------------------------
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println!("----------------------------------------");
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let x = 4;
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let equal_to_x = |z| z == x;
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println!("{}", equal_to_x(4));
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let x = vec![1, 2, 3];
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// move 强制闭包获取其使用的环境值的所有权
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let equal_to_x = move |z| z == x;
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//value used here after move
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// println!("can't use x here: {:?}", x);
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let y = vec![1, 2, 3];
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println!("{}", equal_to_x(y));
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let v1: Vec<i32> = vec![1, 2, 3];
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let v2: Vec<_> = v1.iter().map(|x| x + 1).collect();
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println!("{:?}", v2);
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let shoes = vec![
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Shoe {
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size: 10,
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style: String::from("sneaker"),
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},
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Shoe {
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size: 13,
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style: String::from("sandal"),
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},
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Shoe {
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size: 10,
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style: String::from("boot"),
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},
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];
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let in_my_size = shoes_in_my_size(shoes, 10);
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println!("{:?}", in_my_size);
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let counter = Counter::new();
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let v: Vec<_> = counter.into_iter().map(|x| x + 1).collect();
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println!("{:?}", v);
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let v: Vec<_> = Counter::new()
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.zip(Counter::new().skip(1))
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.map(|(a, b)| a * b)
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.collect();
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println!("{:?}", v);
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||
let sum: u32 = Counter::new()
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.zip(Counter::new().skip(1))
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.map(|(a, b)| a * b)
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.filter(|x| x % 3 == 0)
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.sum();
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println!("{}", sum);
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||
// ---------------------------
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println!("----------------------------------------");
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use crate::List::*;
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let a = Rc::new(Cons(5, RefCell::new(Rc::new(Nil))));
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println!("a initial rc count = {}", Rc::strong_count(&a));
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println!("a next item = {:?}", a.tail());
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let b = Rc::new(Cons(10, RefCell::new(Rc::clone(&a))));
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println!("a rc count after b creation = {}", Rc::strong_count(&a));
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println!("b initial rc count = {}", Rc::strong_count(&b));
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println!("b next item = {:?}", b.tail());
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|
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if let Some(link) = a.tail() {
|
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*link.borrow_mut() = Rc::clone(&b);
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}
|
||
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println!("b rc count after changing a = {}", Rc::strong_count(&b));
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println!("a rc count after changing a = {}", Rc::strong_count(&a));
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||
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// 这会导致栈溢出
|
||
// println!("a next item = {:?}", a.tail());
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// 并不是 a.tail(); 引起死循环，打印函数触发循环引用
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||
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||
// ---------------------------
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println!("----------------------------------------");
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let leaf = Rc::new(Node {
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value: 3,
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parent: RefCell::new(Weak::new()),
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children: RefCell::new(vec![]),
|
||
});
|
||
println!(
|
||
"leaf strong = {}, weak = {}, parent = {:?}",
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Rc::strong_count(&leaf),
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Rc::weak_count(&leaf),
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leaf.parent.borrow().upgrade(),
|
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);
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||
{
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let branch = Rc::new(Node {
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value: 5,
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parent: RefCell::new(Weak::new()),
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children: RefCell::new(vec![Rc::clone(&leaf)]),
|
||
});
|
||
|
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*leaf.parent.borrow_mut() = Rc::downgrade(&branch);
|
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// let leaf = Rc::new(Node {
|
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// value: 3,
|
||
// parent: RefCell::new(Rc::downgrade(&branch)),
|
||
// children: RefCell::new(vec![]),
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||
// });
|
||
|
||
println!(
|
||
"branch strong = {}, weak = {}, parent = {:?}",
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||
Rc::strong_count(&branch),
|
||
Rc::weak_count(&branch),
|
||
branch.parent.borrow().upgrade(),
|
||
);
|
||
|
||
println!(
|
||
"leaf strong = {}, weak = {}, parent = {:?}",
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Rc::strong_count(&leaf),
|
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Rc::weak_count(&leaf),
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||
leaf.parent.borrow().upgrade(),
|
||
);
|
||
} // -> 离开作用域，此时，Rc<branch> 的强引用（strong_count）为 0，但是 Weak<branch> 弱引用数（weak_count）仍然为 1（引用 Weak<branch> 的 Rc<leaf> 仍然存在），
|
||
// weak_count 无需计数为 0 就能使 Rc<branch> 实例被清理。
|
||
println!(
|
||
"leaf strong = {}, weak = {}, parent = {:?}",
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||
Rc::strong_count(&leaf),
|
||
Rc::weak_count(&leaf),
|
||
leaf.parent.borrow().upgrade(),
|
||
);
|
||
|
||
// ---------------------------
|
||
println!("----------------------------------------");
|
||
let x = Rc::new(5);
|
||
let y = *x;
|
||
assert_eq!(5, y);
|
||
|
||
let r = Rc::new("Rust".to_string());
|
||
// Rc 不支持解引用移动
|
||
// let x = *r;
|
||
// println!("{:?}", x);
|
||
println!("{:?}", *r);
|
||
|
||
let x = RefCell::new(5);
|
||
println!("{}", *x.borrow());
|
||
// 变量 x 非 mut，可通过以下代码修改 x 的值
|
||
*x.borrow_mut() = 7;
|
||
println!("{}", *x.borrow());
|
||
|
||
let x = Box::new(5);
|
||
let x1 = *x;
|
||
println!("Box {}", x1);
|
||
|
||
// ---------------------------
|
||
println!("--------函数和方法的隐式解引用强制多态--------------");
|
||
// let m = Box::new(String::from("Rust"));
|
||
let m = MyBox::new(String::from("Rust"));
|
||
//String 上的 Deref 实现: fn deref(&self) -> &str {...}
|
||
|
||
// hello_str(&(*m)[..]);
|
||
// 当所涉及到的类型定义了 Deref trait，Rust 会分析这些类型并使用任意多次 Deref::deref 调用以获得匹配参数的类型
|
||
// &m -> &String -> &str
|
||
hello_str(&m);
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let jh = thread::spawn(|| {
|
||
for i in 1..10 {
|
||
println!("hi number {} from the spawned thread!", i);
|
||
thread::sleep(Duration::from_millis(1));
|
||
}
|
||
});
|
||
|
||
for i in 1..5 {
|
||
println!("hi number {} from the main thread!", i);
|
||
thread::sleep(Duration::from_millis(1));
|
||
}
|
||
jh.join().unwrap();
|
||
|
||
let v = vec![1, 2, 3];
|
||
let handle = thread::spawn(move || {
|
||
println!("Here's a vector: {:?}", v);
|
||
});
|
||
// drop(v);
|
||
// ^ value used here after move
|
||
handle.join().unwrap();
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let (tx, rx) = mpsc::channel();
|
||
let tx1 = mpsc::Sender::clone(&tx);
|
||
thread::spawn(move || {
|
||
let vals = vec![
|
||
String::from("hi"),
|
||
String::from("from"),
|
||
String::from("the"),
|
||
String::from("thread"),
|
||
];
|
||
|
||
for val in vals {
|
||
tx1.send(val).unwrap();
|
||
thread::sleep(Duration::from_millis(50));
|
||
}
|
||
});
|
||
|
||
thread::spawn(move || {
|
||
// tx.send(12).unwrap();
|
||
tx.send(String::from("12")).unwrap();
|
||
});
|
||
|
||
for received in rx {
|
||
println!("Got: {}", received);
|
||
}
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let counter = Arc::new(Mutex::new(0));
|
||
let mut handles = vec![];
|
||
|
||
for _ in 0..10 {
|
||
let counter = Arc::clone(&counter);
|
||
let handle = thread::spawn(move || {
|
||
let mut num = counter.lock().unwrap();
|
||
|
||
*num += 1;
|
||
});
|
||
handles.push(handle);
|
||
}
|
||
|
||
for handle in handles {
|
||
handle.join().unwrap();
|
||
}
|
||
|
||
println!("Result: {}", *counter.lock().unwrap());
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let screen = Screen {
|
||
components: vec![
|
||
Box::new(SelectBox {
|
||
width: 75,
|
||
height: 10,
|
||
options: vec![
|
||
String::from("Yes"),
|
||
String::from("Maybe"),
|
||
String::from("No"),
|
||
],
|
||
}),
|
||
Box::new(Button {
|
||
width: 50,
|
||
height: 10,
|
||
label: String::from("OK"),
|
||
}),
|
||
],
|
||
};
|
||
|
||
screen.run();
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
|
||
let bt = Bt {
|
||
height: 10,
|
||
label: Some(String::from("test")),
|
||
};
|
||
|
||
let h = bt.label.unwrap();
|
||
println!("{}", h);
|
||
// borrow of moved value: `bt`
|
||
// println!("{:?}", bt);
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let favorite_color: Option<&str> = None;
|
||
let is_tuesday = false;
|
||
let age: Result<u8, _> = "34".parse();
|
||
|
||
if let Some(color) = favorite_color {
|
||
println!("Using your favorite color, {}, as the background", color);
|
||
} else if is_tuesday {
|
||
println!("Tuesday is green day!");
|
||
} else if let Ok(age) = age {
|
||
if age > 30 {
|
||
println!("Using purple as the background color");
|
||
} else {
|
||
println!("Using orange as the background color");
|
||
}
|
||
} else {
|
||
println!("Using blue as the background color");
|
||
}
|
||
|
||
let mut stack = Vec::new();
|
||
stack.push(1);
|
||
stack.push(2);
|
||
stack.push(3);
|
||
while let Some(top) = stack.pop() {
|
||
println!("{}", top);
|
||
}
|
||
|
||
let v = vec!['a', 'b', 'c'];
|
||
for (index, value) in v.iter().enumerate() {
|
||
println!("{} is at index {}", value, index);
|
||
}
|
||
|
||
let x: u32 = 5;
|
||
let point = (3, x as i32);
|
||
print_coordinates(&point);
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
// 匹配字面值
|
||
let x = 1;
|
||
match x {
|
||
1 => println!("one"),
|
||
2 => println!("two"),
|
||
3 => println!("three"),
|
||
_ => println!("anything"),
|
||
}
|
||
|
||
// 匹配命名变量
|
||
let x = Some(5);
|
||
let y = 10;
|
||
match x {
|
||
Some(50) => println!("Got 50"),
|
||
Some(y) => println!("Matched, y = {:?}", y),
|
||
_ => println!("Default case, x = {:?}", x),
|
||
}
|
||
println!("at the end: x = {:?}, y = {:?}", x, y);
|
||
|
||
// 多个模式
|
||
let x = 1;
|
||
match x {
|
||
1 | 2 => println!("one or two"),
|
||
3 => println!("three"),
|
||
_ => println!("anything"),
|
||
}
|
||
|
||
// 通过 ... 匹配值的范围
|
||
// 范围只允许用于数字或 char 值
|
||
let x = 5;
|
||
match x {
|
||
1...5 => println!("one through five"),
|
||
_ => println!("something else"),
|
||
}
|
||
|
||
let x = 'c';
|
||
match x {
|
||
'a'...'j' => println!("early ASCII letter"),
|
||
'k'...'z' => println!("late ASCII letter"),
|
||
_ => println!("something else"),
|
||
}
|
||
|
||
// 解构结构体
|
||
struct Point {
|
||
x: i32,
|
||
y: i32,
|
||
}
|
||
let p = Point { x: 0, y: 7 };
|
||
let Point { x: a, y: b } = p;
|
||
assert_eq!(0, a);
|
||
assert_eq!(7, b);
|
||
|
||
let Point { x, y } = p;
|
||
assert_eq!(0, x);
|
||
assert_eq!(7, y);
|
||
|
||
match p {
|
||
Point { x, y: 0 } => println!("On the x axis at {}", x),
|
||
Point { x: 0, y } => println!("On the y axis at {}", y),
|
||
Point { x, y } => println!("On neither axis: ({}, {})", x, y),
|
||
}
|
||
|
||
// 解构枚举
|
||
// let msg = Message::ChangeColor(0, 160, 255);
|
||
let msg = &Message::Move { x: 1, y: 2 };
|
||
// let msg = &Message::Quit;
|
||
match msg {
|
||
Message::Quit => println!("The Quit variant has no data to destructure."),
|
||
Message::Move { x, y } => {
|
||
println!("Move in the x direction {} and in the y direction {}", x, y);
|
||
}
|
||
Message::Write(text) => println!("Text message: {}", text),
|
||
Message::ChangeColor(r, g, b) => {
|
||
println!("Change the color to red {}, green {}, and blue {}", r, g, b)
|
||
}
|
||
}
|
||
|
||
// 解构嵌套的结构体 & 枚举
|
||
let msg = Msg::ChangeColor(Color::Hsv(0, 160, 255));
|
||
match msg {
|
||
Msg::ChangeColor(Color::_Rgb(r, g, b)) => {
|
||
println!("Change the color to red {}, green {}, and blue {}", r, g, b)
|
||
}
|
||
Msg::ChangeColor(Color::Hsv(h, s, v)) => println!(
|
||
"Change the color to hue {}, saturation {}, and value {}",
|
||
h, s, v
|
||
),
|
||
_ => (),
|
||
}
|
||
|
||
// 解构引用
|
||
let points = vec![
|
||
Point { x: 0, y: 0 },
|
||
Point { x: 1, y: 5 },
|
||
Point { x: 10, y: -3 },
|
||
];
|
||
|
||
let sum_of_squares: i32 = points.iter().map(|&Point { x, y }| x * x + y * y).sum();
|
||
println!("{}", sum_of_squares);
|
||
|
||
// 解构结构体和元组
|
||
let ((feet, inches), Point { x, y }) = ((3, 10), Point { x: 3, y: -10 });
|
||
println!("{} {} {} {}", feet, inches, x, y);
|
||
|
||
// 忽略模式中的值
|
||
foo(3, 4);
|
||
fn foo(_: i32, y: i32) {
|
||
println!("This code only uses the y parameter: {}", y);
|
||
}
|
||
|
||
let mut setting_value = Some(5);
|
||
let new_setting_value = Some(10);
|
||
match (setting_value, new_setting_value) {
|
||
(Some(_), Some(_)) => {
|
||
println!("Can't overwrite an existing customized value");
|
||
}
|
||
_ => {
|
||
setting_value = new_setting_value;
|
||
}
|
||
}
|
||
println!("setting is {:?}", setting_value);
|
||
|
||
let numbers = (2, 4, 8, 16, 32);
|
||
match numbers {
|
||
(first, _, third, _, fifth) => println!("Some numbers: {}, {}, {}", first, third, fifth),
|
||
}
|
||
match numbers {
|
||
(first, .., last) => println!("Some numbers: {}, {}", first, last),
|
||
// error: `..` can only be used once per tuple or tuple struct pattern
|
||
// (.., second, ..) => println!("Some numbers: {}", second),
|
||
}
|
||
|
||
// 通过在名字前以一个下划线开头来忽略未使用的变量
|
||
let _x = 5;
|
||
// let y = 10;
|
||
// ^ help: consider prefixing with an underscore: `_y`
|
||
|
||
struct Pt {
|
||
x: i32,
|
||
_y: i32,
|
||
_z: i32,
|
||
}
|
||
let origin = Pt { x: 0, _y: 0, _z: 0 };
|
||
match origin {
|
||
Pt { x, .. } => println!("x is {}", x),
|
||
}
|
||
|
||
// 匹配守卫提供的额外条件
|
||
let num = Some(4);
|
||
match num {
|
||
Some(x) if x < 5 => println!("less than five: {}", x),
|
||
Some(x) => println!("{}", x),
|
||
None => (),
|
||
}
|
||
|
||
let x = 4;
|
||
let y = true;
|
||
match x {
|
||
// 匹配守卫中引用外部变量 y，而不是创建新变量 y
|
||
// if 条件作用于整个 4 | 5 | 6 模式，类似：(4 | 5 | 6) if y => println!("yes"),
|
||
4 | 5 | 6 if y => println!("yes"),
|
||
_ => println!("no"),
|
||
}
|
||
|
||
// 使用 @ 可以在一个模式中同时测试和保存变量值。
|
||
enum Ms {
|
||
Hello { id: i32 },
|
||
}
|
||
let msg = Ms::Hello { id: 5 };
|
||
match msg {
|
||
Ms::Hello { id: id_var @ 3...7 } => println!("Found an id in range: {}", id_var),
|
||
// 此匹配分支不能使用 id
|
||
Ms::Hello { id: 10...12 } => println!("Found an id in another range"),
|
||
Ms::Hello { id } => println!("Found some other id: {}", id),
|
||
}
|
||
|
||
// 遗留模式： ref 和 ref mut
|
||
let robot_name = &Some(String::from("Bors"));
|
||
match robot_name {
|
||
Some(name) => println!("Found a name: {}", name),
|
||
// 老版本中会如下使用
|
||
// &Some(ref name) => println!("Found a name: {}", name),
|
||
None => (),
|
||
}
|
||
println!("robot_name is: {:?}", robot_name);
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let mut num = 5;
|
||
let r1 = &num as *const i32; // 不可变的裸指针
|
||
let r2 = &mut num as *mut i32; // 可变的裸指针
|
||
unsafe {
|
||
println!("r1 is: {}", *r1);
|
||
println!("r2 is: {}", *r2);
|
||
}
|
||
|
||
unsafe fn dangerous() {
|
||
println!("this dangerous function");
|
||
}
|
||
unsafe {
|
||
dangerous();
|
||
}
|
||
|
||
let mut v = vec![1, 2, 3, 4, 5, 6];
|
||
let r = &mut v[..];
|
||
// let (a, b) = r.split_at_mut(3);
|
||
let (a, b) = split_at_mut(r, 3);
|
||
println!("{:?}", a);
|
||
println!("{:?}", b);
|
||
|
||
// 使用 extern 函数调用外部 C 语言代码
|
||
extern "C" {
|
||
fn abs(input: i32) -> i32;
|
||
}
|
||
unsafe {
|
||
println!("Absolute value of -3 according to C: {}", abs(-3));
|
||
}
|
||
|
||
// 定义可供 C 语言调用的函数
|
||
#[no_mangle]
|
||
pub extern "C" fn call_from_c() {
|
||
println!("Just called a Rust function from C!");
|
||
}
|
||
|
||
// 静态变量
|
||
// 访问不可变静态变量是安全的
|
||
static HELLO_WORLD: &str = "Hello, world!";
|
||
println!("name is: {}", HELLO_WORLD);
|
||
|
||
// 访问和修改可变静态变量都是 不安全 的
|
||
add_to_count(3);
|
||
unsafe {
|
||
println!("COUNTER: {}", COUNTER);
|
||
}
|
||
|
||
unsafe trait Foo {
|
||
// methods go here
|
||
}
|
||
unsafe impl Foo for i32 {
|
||
// method implementations go here
|
||
}
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
struct Context<'s>(&'s str);
|
||
// 声明一个不短于 'c 的生命周期 's。
|
||
// struct Parser<'c, 's: 'c> {
|
||
struct Parser<'c, 's> {
|
||
context: &'c Context<'s>,
|
||
}
|
||
impl<'c, 's> Parser<'c, 's> {
|
||
fn parse(&self) -> Result<(), &'s str> {
|
||
Err(&self.context.0[1..])
|
||
}
|
||
}
|
||
fn parse_context(context: Context) -> Result<(), &str> {
|
||
Parser { context: &context }.parse()
|
||
}
|
||
|
||
let centext = Context("test");
|
||
match parse_context(centext) {
|
||
Err(s) => println!("{}", s),
|
||
_ => (),
|
||
}
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
trait Red {}
|
||
struct Ball<'a> {
|
||
diameter: &'a i32,
|
||
}
|
||
// impl<'a> Red for Ball<'a> {}
|
||
impl Red for Ball<'_> {}
|
||
|
||
let num = 5;
|
||
let obj = Box::new(Ball { diameter: &num }) as Box<dyn Red>;
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
struct StrWrap<'a>(&'a str);
|
||
// '_ 表明在此处使用省略的生命周期,这意味着我们仍然知道 StrWrap 包含一个引用，不过无需所有的生命周期注解来知道。
|
||
// fn foo<'a>(string: &'a str) -> StrWrap<'a> {
|
||
fn fsw(string: &str) -> StrWrap<'_> {
|
||
StrWrap(string)
|
||
}
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
fn add_one(x: i32) -> i32 {
|
||
x + 1
|
||
}
|
||
fn do_twice(f: fn(i32) -> i32, arg: i32) -> i32 {
|
||
f(arg) + f(arg)
|
||
}
|
||
let answer = do_twice(add_one, 5);
|
||
println!("The answer is: {}", answer);
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
let list_of_numbers = vec![1, 2, 3];
|
||
let list_of_strings: Vec<String> = list_of_numbers.iter().map(ToString::to_string).collect();
|
||
// let list_of_strings: Vec<String> = list_of_numbers.iter().map(|i| i.to_string()).collect();
|
||
println!("{:?}", list_of_strings);
|
||
|
||
#[derive(Debug)]
|
||
enum Status {
|
||
Value(u32),
|
||
Stop,
|
||
}
|
||
let list_of_statuses: Vec<Status> = (0u32..20).map(Status::Value).collect();
|
||
// let list_of_statuses: Vec<Status> = (0u32..20).map(|i| Status::Value(i)).collect();
|
||
println!("{:?}", list_of_statuses);
|
||
|
||
fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
|
||
Box::new(|x| x + 1)
|
||
}
|
||
let rc = returns_closure();
|
||
println!("{}", rc(12));
|
||
|
||
// ---------------------------
|
||
println!("---------------------------");
|
||
use hello_macro::HelloMacro;
|
||
use hello_macro_derive::HelloMacro;
|
||
|
||
#[derive(HelloMacro)]
|
||
struct Pancakes;
|
||
|
||
Pancakes::hello_macro();
|
||
|
||
let user1 = User {
|
||
username: String::from("hllo"),
|
||
email: String::from("hell@world.com"),
|
||
sign_in_count: 1,
|
||
active: false,
|
||
};
|
||
println!("{:?}", user1);
|
||
|
||
let s: &str = "Hello";
|
||
println!("{}", s);
|
||
let mut s: String = "Hello".to_string();
|
||
let w = "World";
|
||
s.push_str(w);// 并不需要获取 w 的所有权
|
||
s.push('!');
|
||
println!("{} {}", s, w);
|
||
|
||
let t = (1, "34");
|
||
test_tuple(t);
|
||
println!("{} {}", t.0, t.1);
|
||
|
||
let s1 = String::from("Hello, ");
|
||
let s2 = String::from("World!");
|
||
let s3 = s1 + &s2; // 注意 s1 被移动了，不能继续使用
|
||
// println!("{} {} {}", s1, s3, s2);
|
||
println!("{} {}", s3, s2);
|
||
|
||
for c in "नमˑे".chars() {
|
||
println!("{}", c);
|
||
}
|
||
for b in "नमˑे".bytes() {
|
||
println!("{}", b);
|
||
}
|
||
let hello = "Здравствуйте";
|
||
let s = &hello[0..4];
|
||
println!("&hello[0..4]={}", s);
|
||
}
|
||
|
||
fn test_tuple(t: (i32, &str)) {
|
||
println!("{} {}", t.0, t.1);
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct User {
|
||
username: String,
|
||
email: String,
|
||
sign_in_count: u64,
|
||
active: bool,
|
||
}
|
||
|
||
static mut COUNTER: u32 = 0;
|
||
|
||
fn add_to_count(inc: u32) {
|
||
unsafe {
|
||
COUNTER += inc;
|
||
}
|
||
}
|
||
|
||
use std::io::Read;
|
||
use std::slice;
|
||
|
||
fn split_at_mut(slice: &mut [i32], mid: usize) -> (&mut [i32], &mut [i32]) {
|
||
// let len = slice.len();
|
||
// assert!(mid <= len);
|
||
// (&mut slice[..mid], &mut slice[mid..])
|
||
|
||
let len = slice.len();
|
||
let ptr = slice.as_mut_ptr();
|
||
|
||
assert!(mid <= len);
|
||
|
||
unsafe {
|
||
(
|
||
slice::from_raw_parts_mut(ptr, mid),
|
||
slice::from_raw_parts_mut(ptr.offset(mid as isize), len - mid),
|
||
)
|
||
}
|
||
}
|
||
|
||
fn print_coordinates(&(x, y): &(i32, i32)) {
|
||
println!("Current location: ({}, {})", x, y);
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Bt {
|
||
height: u32,
|
||
label: Option<String>,
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct SelectBox {
|
||
width: u32,
|
||
height: u32,
|
||
options: Vec<String>,
|
||
}
|
||
|
||
impl Draw for SelectBox {
|
||
fn draw(&self) {
|
||
// code to actually draw a select box
|
||
println!("{:?}", self);
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
pub struct Button {
|
||
pub width: u32,
|
||
pub height: u32,
|
||
pub label: String,
|
||
}
|
||
|
||
impl Draw for Button {
|
||
fn draw(&self) {
|
||
// 实际绘制按钮的代码
|
||
println!("{:?}", self);
|
||
}
|
||
}
|
||
|
||
pub struct Screen {
|
||
pub components: Vec<Box<dyn Draw>>,
|
||
}
|
||
|
||
impl Screen {
|
||
pub fn run(&self) {
|
||
for component in self.components.iter() {
|
||
component.draw();
|
||
}
|
||
}
|
||
}
|
||
|
||
pub trait Draw {
|
||
fn draw(&self);
|
||
}
|
||
|
||
struct MyBox<T>(T);
|
||
|
||
impl<T> MyBox<T> {
|
||
fn new(x: T) -> MyBox<T> {
|
||
MyBox(x)
|
||
}
|
||
}
|
||
|
||
impl<T> Deref for MyBox<T> {
|
||
type Target = T;
|
||
|
||
fn deref(&self) -> &T {
|
||
&self.0
|
||
}
|
||
}
|
||
|
||
fn hello_str(name: &str) {
|
||
println!("Hello, {}!", name);
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
enum List {
|
||
Cons(i32, RefCell<Rc<List>>),
|
||
Nil,
|
||
}
|
||
|
||
impl List {
|
||
fn tail(&self) -> Option<&RefCell<Rc<List>>> {
|
||
use crate::List::*;
|
||
match self {
|
||
Cons(_, item) => Some(item),
|
||
Nil => None,
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Node {
|
||
value: i32,
|
||
parent: RefCell<Weak<Node>>,
|
||
children: RefCell<Vec<Rc<Node>>>,
|
||
}
|
||
|
||
fn change(some_string: &mut String) {
|
||
some_string.push_str(", world");
|
||
}
|
||
|
||
//enum IpAddrKind {
|
||
// V4,
|
||
// V6,
|
||
//}
|
||
|
||
#[derive(Debug)]
|
||
enum IpAddr {
|
||
V4(u8, u8, u8, u8),
|
||
V6(String),
|
||
}
|
||
|
||
enum Color {
|
||
_Rgb(i32, i32, i32),
|
||
Hsv(i32, i32, i32),
|
||
}
|
||
|
||
enum Msg {
|
||
_Quit,
|
||
ChangeColor(Color),
|
||
}
|
||
|
||
// Quit 没有关联任何数据。
|
||
// Move 包含一个匿名结构体。
|
||
// Write 包含单独一个 String。
|
||
// ChangeColor 包含三个 i32。
|
||
#[derive(Debug)]
|
||
enum Message {
|
||
Quit,
|
||
Move { x: i32, y: i32 },
|
||
Write(String),
|
||
ChangeColor(i32, i32, i32),
|
||
}
|
||
|
||
impl Message {
|
||
fn call(&self) {
|
||
println!("this message call.");
|
||
}
|
||
}
|
||
|
||
//fn first_words<'a>(s: &'a str) -> &'a str {
|
||
fn first_words(s: &str) -> &str {
|
||
let b = s.as_bytes();
|
||
for (i, &item) in b.iter().enumerate() {
|
||
if item == b' ' {
|
||
return &s[0..i];
|
||
}
|
||
}
|
||
|
||
&s[..]
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Rectangle {
|
||
width: u32,
|
||
height: u32,
|
||
}
|
||
|
||
impl Rectangle {
|
||
fn area(&self) -> u32 {
|
||
self.width * self.height
|
||
}
|
||
|
||
fn can_hold(&self, other: &Rectangle) -> bool {
|
||
self.width > other.width && self.height > other.height
|
||
}
|
||
|
||
fn square(size: u32) -> Rectangle {
|
||
Rectangle {
|
||
width: size,
|
||
height: size,
|
||
}
|
||
}
|
||
}
|
||
|
||
mod sound {
|
||
pub mod instrument {
|
||
pub fn clarinet() {
|
||
println!("this clarinet");
|
||
}
|
||
}
|
||
}
|
||
|
||
mod performance_group {
|
||
pub use crate::sound::instrument;
|
||
|
||
pub fn clarinet_trio() {
|
||
instrument::clarinet();
|
||
instrument::clarinet();
|
||
instrument::clarinet();
|
||
}
|
||
}
|
||
|
||
// 传播错误
|
||
fn read_username_from_file() -> Result<String, io::Error> {
|
||
// 1.
|
||
let f = File::open("hello.txt");
|
||
|
||
let mut f = match f {
|
||
Ok(file) => file,
|
||
Err(error) => return Err(error),
|
||
};
|
||
|
||
let mut s = String::new();
|
||
match f.read_to_string(&mut s) {
|
||
Ok(_) => Ok(s),
|
||
Err(e) => Err(e),
|
||
}
|
||
|
||
// 2.
|
||
// let mut f = File::open("hello.txt")?;
|
||
//
|
||
// let mut s = String::new();
|
||
// f.read_to_string(&mut s)?;
|
||
// Ok(s)
|
||
|
||
// 3.
|
||
// let mut s = String::new();
|
||
// File::open("hello.txt")?.read_to_string(&mut s)?;
|
||
// Ok(s)
|
||
|
||
// 4.
|
||
// fs::read_to_string("hello.txt")
|
||
}
|
||
|
||
trait Summary {
|
||
fn summarize_author(&self) -> String;
|
||
|
||
fn summarize(&self) -> String {
|
||
format!("(Read more from {}...)", self.summarize_author())
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Tweet {
|
||
pub username: String,
|
||
pub content: String,
|
||
pub reply: bool,
|
||
pub retweet: bool,
|
||
}
|
||
|
||
impl Summary for Tweet {
|
||
fn summarize_author(&self) -> String {
|
||
format!("@{}", self.username)
|
||
}
|
||
}
|
||
|
||
impl ToString for Tweet {
|
||
fn to_string(&self) -> String {
|
||
format!("{:?}", self)
|
||
}
|
||
}
|
||
|
||
//fn notify<T: Summary + ToString, U: Summary>(t: &T, u: &U) -> String {
|
||
// format!("{}, {}", u.summarize(), t.to_string())
|
||
//}
|
||
|
||
//fn notify(t: &(impl Summary + ToString), u: &(impl Summary)) -> String {
|
||
// format!("{}, {}", u.summarize(), t.to_string())
|
||
//}
|
||
|
||
fn notify<T, U>(t: &T, u: &U) -> String
|
||
where
|
||
T: Summary + ToString,
|
||
U: Summary,
|
||
{
|
||
format!("{}, {}", u.summarize(), t.to_string())
|
||
}
|
||
|
||
// 返回实现了指定 trait 的方法
|
||
fn returns_summarizable() -> impl Summary {
|
||
Tweet {
|
||
username: String::from("horse_ebooks"),
|
||
content: String::from("of course, as you probably already know, people"),
|
||
reply: false,
|
||
retweet: false,
|
||
}
|
||
}
|
||
|
||
fn largest<T: PartialOrd + Copy>(list: &[T]) -> T {
|
||
//fn largest(list: &[impl PartialOrd + Copy]) -> impl PartialOrd + Copy {
|
||
//fn largest<T>(list: &[T]) -> T
|
||
// where T: PartialOrd + Copy {
|
||
let mut largest = list[0];
|
||
|
||
for &item in list.iter() {
|
||
if item > largest {
|
||
largest = item;
|
||
}
|
||
}
|
||
|
||
// for item in list.iter() {
|
||
// if *item > largest {
|
||
// largest = *item;
|
||
// }
|
||
// }
|
||
|
||
return largest;
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Pair<T> {
|
||
x: T,
|
||
y: T,
|
||
}
|
||
|
||
impl<T> Pair<T> {
|
||
fn new(x: T, y: T) -> Self {
|
||
Self { x, y }
|
||
}
|
||
}
|
||
|
||
// 只有那些为 T 类型实现了 PartialOrd trait（来允许比较）和 Display trait（来启用打印）的 Pair<T> 才会实现 cmp_display 方法
|
||
impl<T: Display + PartialOrd> Pair<T> {
|
||
fn cmp_display(&self) {
|
||
if self.x >= self.y {
|
||
println!("The largest member is x = {}", self.x);
|
||
} else {
|
||
println!("The largest member is y = {}", self.y);
|
||
}
|
||
}
|
||
}
|
||
|
||
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
|
||
if x.len() > y.len() {
|
||
x
|
||
} else {
|
||
y
|
||
}
|
||
}
|
||
|
||
struct Cacher<T, D, F>
|
||
where
|
||
T: Fn(&D) -> F,
|
||
{
|
||
calculation: T,
|
||
value: HashMap<D, F>,
|
||
}
|
||
|
||
impl<T, D, F> Cacher<T, D, F>
|
||
where
|
||
D: Hash + Eq,
|
||
F: Copy,
|
||
T: Fn(&D) -> F,
|
||
{
|
||
fn new(calculation: T) -> Cacher<T, D, F> {
|
||
Self {
|
||
calculation,
|
||
value: HashMap::<D, F>::new(),
|
||
}
|
||
}
|
||
|
||
fn value(&mut self, args: D) -> F {
|
||
match self.value.get(&args) {
|
||
Some(&v) => v,
|
||
None => {
|
||
let v = (self.calculation)(&args);
|
||
let v1 = v.clone();
|
||
|
||
self.value.insert(args, v);
|
||
|
||
v1
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn generate_workout(intensity: u32, random_number: u32) {
|
||
// let calculation = |num: u32| -> u32 {
|
||
// println!("calculating slowly...");
|
||
// thread::sleep(Duration::from_secs(2));
|
||
// num
|
||
// };
|
||
|
||
let mut expensive_result = Cacher::new(|num| {
|
||
println!("calculating slowly...");
|
||
thread::sleep(Duration::from_millis(500));
|
||
num + 1
|
||
});
|
||
|
||
if intensity < 25 {
|
||
println!("Today, do {} pushups!", expensive_result.value(intensity));
|
||
println!("Next, do {} situps!", expensive_result.value(intensity));
|
||
} else {
|
||
if random_number == 3 {
|
||
println!("Take a break today! Remember to stay hydrated!");
|
||
} else {
|
||
println!(
|
||
"Today, run for {} minutes!",
|
||
expensive_result.value(intensity)
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
struct Shoe {
|
||
size: u32,
|
||
style: String,
|
||
}
|
||
|
||
fn shoes_in_my_size(shoes: Vec<Shoe>, shoe_size: u32) -> Vec<Shoe> {
|
||
shoes
|
||
// .iter() // a collection of type `std::vec::Vec<Shoe>` cannot be built from `std::iter::Iterator<Item=&Shoe>`
|
||
.into_iter() //获取 vector 所有权的迭代器
|
||
.filter(|s| s.size == shoe_size)
|
||
.collect()
|
||
}
|
||
|
||
struct Counter {
|
||
count: u32,
|
||
}
|
||
|
||
impl Counter {
|
||
fn new() -> Counter {
|
||
Counter { count: 0 }
|
||
}
|
||
}
|
||
|
||
impl Iterator for Counter {
|
||
type Item = u32;
|
||
|
||
fn next(&mut self) -> Option<Self::Item> {
|
||
self.count += 1;
|
||
|
||
if self.count < 6 {
|
||
Some(self.count)
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
#[test]
|
||
fn call_with_different_values() {
|
||
let mut c = Cacher::new(|a| {
|
||
println!("cal: {}", a);
|
||
a + 1
|
||
});
|
||
|
||
let v1 = c.value(2);
|
||
let v1 = c.value(2);
|
||
assert_eq!(v1, 3);
|
||
|
||
let v2 = c.value(-2);
|
||
assert_eq!(v2, -1);
|
||
}
|
||
|
||
#[test]
|
||
fn call_with_different_type() {
|
||
let mut c = Cacher::new(|a| {
|
||
println!("\ncal: {}", a);
|
||
7
|
||
});
|
||
|
||
let v = c.value("tetsss");
|
||
assert_eq!(v, 7);
|
||
}
|
||
|
||
#[test]
|
||
fn iterator_demonstration() {
|
||
let v1 = vec![1, 2, 3];
|
||
let mut v1_iter = v1.iter();
|
||
|
||
assert_eq!(v1_iter.next(), Some(&1));
|
||
assert_eq!(v1_iter.next(), Some(&2));
|
||
assert_eq!(v1_iter.next(), Some(&3));
|
||
assert_eq!(v1_iter.next(), None);
|
||
}
|
||
|
||
#[test]
|
||
fn iterator_sum() {
|
||
let v1 = vec![1, 2, 3];
|
||
let v1_iter = v1.iter();
|
||
let total: i32 = v1_iter.sum();
|
||
|
||
assert_eq!(total, 6);
|
||
}
|
||
}
|