RustでFizzBuzz

rust_fizz_buzz.rs

use std::fmt;

fn main() {
    println!("Hello, world!");
    for i in 1..100 {
      println!("{}", fizz_buzz(i))
    }
}

enum FBN<'a> {
    FString(&'a str),
    FInteger(i32),
}

impl<'a> From<&'a str> for FBN<'a> {
    fn from(str: &'a str) -> Self {
        FBN::FString(str)
    }
}

impl<'a> From<i32> for FBN<'a> {
    fn from(num: i32) -> Self {
        FBN::FInteger(num)
    }
}

impl<'a> fmt::Display for FBN<'a> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
          &FBN::FString(v) => write!(f, "{}", v),
          &FBN::FInteger(n) => write!(f, "{}", n),
        }
    }
}

fn fizz_buzz<'a>(num: i32) -> FBN<'a> {
    match num {
       _ if num % 15 == 0 => FBN::from("FizzBuzz"),      
       _ if num % 3 == 0  => FBN::from("Fizz"),
       _ if num % 5 == 0  => FBN::from("Buzz"),
       num                => FBN::from(num),
    }
}