FnMap

FnMap是对HashMap的抽象，类似于TypeMap。但它使用闭包的类型（每个闭包的类型在Rust中是唯一的）作为键，并存储产生的值。允许像有效的低成本依赖注入容器一样使用。

用法

use fn_map::FnMap;

let map = FnMap::new();

fn one() -> i32 {
    println!("one computed");
    1
}

// get or compute(and insert) value using given closure. The closure depends on value of `one` function to compute its output.
let a = *map.get(|| map.get(one) + 1);
dbg!(a);

// b is *not* a because each closure's type is unique
let b = *map.get(|| map.get(one) + 1);
dbg!(b);

// get or compute(and insert) value using give function. But will not compute since it is computed already when producing a.
let c = *map.get(one);
dbg!(c);

将输出

one computed
a = 2
b = 2
c = 1

许可证

MIT