使用对比较运算符或函数的引用来比较某些值

Question

有没有办法在 Rust 中引用比较运算符或函数来比较某些值？所以我的想法是...

enum SomeEnum {
    A,
    B,
}

let some_enum = SomeEnum::A;
let a = 1;
let b = 2;

// What would be nice ...
let op = match some_enum {
    SomeEnum::A => {
        ge_operator // return greater_equal operator - how could this work?
    }
    SomeEnum::B => {
       ls_operator // return less operator - how could this work?
    }
};
    
let test = if a op b {
    'X'
} else {
    'Y'
};

Answer 1

您可以return 函数根据需要在匹配范围内：

// What would be nice ...
let op = match some_enum {
    SomeEnum::A => {
        <u32 as PartialOrd<u32>>::ge // return greater_equal operator - how could this work?
    }
    SomeEnum::B => {
        <u32 as PartialOrd<u32>>::lt // return less operator - how could this work?
    }
};

Playground

正如@eggyal 指出的，rust 甚至可以推断类型：

let op = match some_enum {
    SomeEnum::A => PartialOrd::ge,
    SomeEnum::B => PartialOrd::lt,
};

使用对比较运算符或函数的引用来比较某些值

Use a reference to a compare operator or function to compare some values

rust

reference

compare

operators