笔者目前接触到的编程语言有java php python golang c/c lua scala erlang。
最近在了解rust，怎样通过rust去构建业务系统呢。
使用rust的理由
- 无gc
- 内存安全，编译器强大
- 零成本抽象，你不必为你的抽象付出一些额外的代价，因为编译器帮你做了，不会在运行时产生额外的开销
安装
- curl http://sh.rustup.rs -sSf | sh 更新 rustup update
和其他语言一样，支持基本的类型
- i8 i16 i32 i64 i128
- f32 f64 T,N str (T,U) fn(i32) -> i32
变量声明的类型在后面，前面需要加上:。比如 let mut I1:u8 = 12321
变量申明使用let，变量默认不可变，可变需要关键字mut
函数 fn开头
支持闭包
支持字符串&str(栈)和String(堆)
支持条件判断 if while for
支持match有点像switch
支持自定义类型 tuple，struct
支持enum，enum可以支持多种不同的类型，这点很有用
通过定义struct或者enum，代码impl xxx 实现类似类的定义
支持包的管理 module import use
支持各类集合 list array slice hashmap
附上一些练习代码
代码语言：rust复制use std::env;
use std::collections::HashMap;
fn add(a :u64, b :u64)-> u64 {
a b
}
fn req_status() -> u32 {
400
}
#[derive(Debug)]
struct Ai;
struct Color(u8,u8,u8);
struct People{
name:String,
age:u8,
weight:u8,
}
impl People {
fn new(name: &str, age:u8, weight:u8) -> People {
People{
name :name.to_string(),
age :age,
weight :weight
}
}
fn get_age(&self) -> u8 {
self.age
}
fn set_age(&mut self, age: u8) {
self.age = age
}
}
enum Shape {
Clz {
name :String
},
S2{
location:String,
timestamp:u64
}
}
fn main() {
let str1 = env::args().skip(1).next();
match str1 {
Some(str1) => println!("hi {}", str1),
None => panic!("match failed")
}
let name = "tom";
println!("my name is {}", name);
let add_result = add(321, 114);
println!(" 321 114 = {}",add_result);
let sqx = |x| x * x;
let twice = sqx(5);
let b_closure = |b, c|{
let z = b c;
z * twice
};
println!("xx={}", b_closure(1,1));
let str2: String = "bobo".to_string();
let str3 = String::from("this is str3");
println!("{},{}", str2, str3);
let a = 12;
if a > 12 {
println!("a is big then 12")
} else {
println!("a is not big then 12")
}
let result = if 1 == 2 {
"1 == 2"
}else {
"1 != 2"
};
println!("result={}", result);
let status = req_status();
match status {
200 => println!("success"),
400 => println!("found failed"),
other => {
println!("other code={}", other);
}
}
let mut x = 3;
'increment: loop {
if x < 0 {
break 'increment;
}
println!("x={}",x);
x -= 1;
}
let mut x = 3;
while x > 0 {
println!("x={}",x);
if x < 0 {
break ;
}
x -= 1;
}
let ai = Ai;
let color1 = Color(255,255,255);
println!("{},{},{}", color1.0, color1.1, color1.2);
let people = People{
name:"tom".to_string(),
age:12,
weight:100
};
println!("{},{},{}", people.name, people.age, people.weight);
let shape1 = Shape::Clz{
name:"tim".to_string(),
};
match shape1 {
Shape::Clz{name} => {
println!("name= {}", name);
},
Shape::S2{location,timestamp} => {
println!("location= {}", location);
},
_ => {
println!("other")
}
}
let p2 = People::new("tom", 12, 100);
println!("{},{},{}", p2.name, p2.age, p2.weight);
//集合
//array
let numbers:[u8;10] = [1,2,3,4,5,6,7,8,9,11];
let floats = [0.3f64,0.5,0.111];
println!("floats[1]:{}", numbers[1]);
println!("floats[1]:{}", floats[1]);
//tuple
let i_i_str :(u8,u8, &str) = (40,12, "hi");
println!("{:?}", i_i_str);
//list
let mut list1:Vec<u8> = Vec::new();
list1.push(1);
list1.push(2);
println!("idx1={}", list1[1]);
//hash
let mut hash1 = HashMap::new();
hash1.insert("a", 1);
hash1.insert("b", 2);
for (k,v) in &hash1{
println!("i got {}={}", v, k);
}
//slice
let mut ns:[u8;4] = [1,2,3,4];
let step2:&[u8] = &ns[0..2];
println!("{:?}", step2);
}
