Show LED numbers.

lednumbers.rs

#![feature(core)]
#![feature(unicode)]

extern crate core;

use std::io;
use std::io::Write;
use core::str::FromStr;


static NUMS: [[&'static str; 3]; 10] = [
    [" _ ", "| |", "|_|"],
    ["   ", "  |", "  |"],
    [" _ ", " _|", "|_ "],
    [" _ ", " _|", " _|"],
    ["   ", "|_|", "  |"],
    [" _ ", "|_ ", " _|"],
    [" _ ", " _|", "|_|"],
    [" _ ", "  |", "  |"],
    [" _ ", "|_|", "|_|"],
    [" _ ", "|_|", "  |"]];


fn to_led(num: &str) -> String {
    let ns = num.graphemes(true)
                .filter_map(|s| usize::from_str(s).ok())
                .collect::<Vec<_>>();

    let mut led = String::new();
    for i in 0..3 {
        for n in ns.clone() {
            led = led + NUMS[n][i];
        }
        led = led + "\n";
    }
    
    led
}


fn main() {
    loop {
        print!("input number: ");
        io::stdout().flush().unwrap();
        let mut num = String::new();
        io::stdin().read_line(&mut num).unwrap();
        
        let led = to_led(&num.trim_right());
        println!("{}", led);
    }
}