morse code decoder in Rust, converted from morse.py by ChatGPT 3.5, no errors!

morse.rs

use std::collections::HashMap;

fn main() {
    let morse: Vec<&str> = vec![
        " ", "-.-.--", ".-..-.", "", "...-..-", "", ".-...", ".----.", "-.--.", "-.--.-", "",
        ".-.-.", "--..--", "-....-", ".-.-.-", "-..-.", "-----", ".----", "..---", "...--",
        "....-", ".....", "-....", "--...", "---..", "----.", "---...", "-.-.-.", "", "-...-",
        "", "..--..", ".--.-.", ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..",
        ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-",
        "...-", ".--", "-..-", "-.--", "--..", "", "", "", "", "..--.-"
    ];

    let mut ascii_value = 32;
    let mut morse_ascii: HashMap<String, char> = HashMap::new();

    for m in morse.iter() {
        let ch = std::char::from_u32(ascii_value).unwrap();
        if !m.is_empty() {
            morse_ascii.insert(m.to_string(), ch);
        }
        ascii_value += 1;
    }

    // alternative to hashmap; use a bit encoding with a leading 1 bit:
    fn encode_morse(m: &str) -> u8 {
        let mut x = 1; // leading 1 bit
        for c in m.chars() {
            x <<= 1;
            x += (c == '-') as i8; 
        }
        // debugging:
        // println!("{:8} => {:3} => {:9b}", m, x as u8, x);
        return x as u8;
    }
    //equivalent: array or vec 
    //let mut morse_ascii_vec: Vec<u8> = vec![0; 256];
    let mut morse_ascii_vec: [u8; 256] = [0;256];
    ascii_value = 32;
    for m in morse.iter() {
        let x = encode_morse(m);
        morse_ascii_vec[x as usize] = ascii_value as u8;
        ascii_value += 1;
    }

    let message = "... --- ..."; // SOS
    let mut decoded_message = String::new();

    for w in message.split_whitespace() {
        if let Some(ch) = morse_ascii.get(w) {
            decoded_message.push(*ch);
        }
    }

    println!("{}", decoded_message);

    // alternate implementation uses a direct array
    let mut decoded_message = String::new();
    for w in message.split_whitespace() {
        let ch = morse_ascii_vec[encode_morse(w) as usize];
        decoded_message.push(ch as char);
    }

    println!("{}", decoded_message);

}