meta {
    line := [line: str] => line;
    photo := repeat line;
    person := [
            first_name: str,
            last_name: str,
            age: f64,
            ph <- photo:"photo",
        ] => {
            first_name: first_name,
            last_name: last_name,
            age: age,
            photo: {
                buf := ""
                for i len(ph) {
                    buf += ph[i] + "\n"
                }
                clone(buf)
            }
        };
    doc := repeat person:"person";
    -------------------------------
    doc
}
