parser.rs

    pub fn high_bin(&mut self) -> Option<Box<Expr<'a>>> {
        let left = self.term()?;
        let bin = self
            .lexer
            .collect_of_if(&[Token::Div, Token::Mul, Token::Mod]);
        if let Some(x) = bin {
            // TODO:: Error if expr is none
            let right = self.term()?;
            return some_expr!(BinOp, left, x.token, right);
        }
        return Some(left);
    }