FizzBuzzGenerator

fizz_buzz_generator.rs

#![feature(inclusive_range_syntax, generators, generator_trait, never_type)]

use std::ops::{Generator, GeneratorState};

fn is_div_by(n: u64, modulus: u64) -> bool {
    if n % modulus == 0 {
        true
    } else {
        false
    }
}

struct FizzBuzzGenerator {
    number: u64
}

impl FizzBuzzGenerator {
    fn new() -> FizzBuzzGenerator {
        FizzBuzzGenerator{number: 0}
    }
}

impl Generator for FizzBuzzGenerator {
    type Yield = String;
    type Return = !;

    fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return> {
        let is_div_by_3 = is_div_by(self.number, 3);
        let is_div_by_5 = is_div_by(self.number, 5);

        let answer: String = match (is_div_by_3, is_div_by_5) {
            (true, false) => "Fizz".to_string(),
            (false, true) => "Buzz".to_string(),
            (true, true) => "FizzBuzz".to_string(),
            _ => format!("{}", self.number),
        };

        self.number += 1;
        GeneratorState::Yielded(answer)
    }
}

fn main() {
    let mut fizz_buzz_generator = FizzBuzzGenerator::new();

    loop {
        match fizz_buzz_generator.resume() {
            GeneratorState::Yielded(answer) => println!("{}", answer),
        }
    }
}