enum TokenType {
    InvalidChar,
    MalformedString,
    MalformedComment,
    Int,
    Plus,
    Minus,
    Asterisk,
    Slash,
    Percent,
    LParen,
    RParen,
}

struct Position {
    index: usize,
    line: i32,
    col: i32,
}

struct Token {
    token_type: TokenType,
    pos: Position,
    length: usize,
}

struct Lexer<'a> {
    text: &'a str,
    i: i32,
}

impl<'a> Lexer<'a> {
    pub fn new(text: &'a str) -> Self {
        Self { text, i: 0 }
    }
}

impl<'a> Iterator for Lexer<'a> {
    type Item = Token;

    fn next(&mut self) -> Option<Self::Item> {
        todo!()
    }
}

fn main() {
    println!("Hello, world!");
}