lazy_fn

lazy_static 为函数提供支持！

使属性函数 "lazy"，它只会被评估一次，并将结果缓存起来，从而作为静态引用返回。

用法

在您的 Cargo.toml

[dependencies]
lazy_fn = "1"
lazy_static = "1"

在您的代码中

#[macro_use] extern crate lazy_fn;

#[lazy_fn]
fn maths() -> i32 {
    9 + 10
}

#[lazy_fn]
fn hello_world() -> &'static str {
    "hello, world!"
}

#[lazy_fn]
fn hello_fmt() -> String {
    format!("hello, {}!", "world")
}

let maths: &'static i32 = maths();
let hello_world: &'static str = hello_world();
let hello_fmt: &'static String = hello_fmt();

lib.rs:

lazy_static 为函数提供支持！

用法

在您的 Cargo.toml

[dependencies]
lazy_fn = "1"
lazy_static = "1"

#[lazy_fn]
fn maths() -> i32 {
    9 + 10
}

#[lazy_fn]
fn hello_world() -> &'static str {
    "hello, world!"
}

#[lazy_fn]
fn hello_fmt() -> String {
    format!("hello, {}!", "world")
}

let maths: &'static i32 = maths();
let hello_world: &'static str = hello_world();
let hello_fmt: &'static String = hello_fmt();