multiple policies, effects, matchers support about casbin-rs HOT 4 OPEN

// compile only once
 static ref EXR_P: Regex = Regex::new(r"\b(?P<ptype>p\d*)_").unwrap();

pub fn extract_ptype_from_matcher(m: &str) -> Option<String> {
    let mut ptype: Option<String> = None;

    for caps in EXR_P.captures_iter(m) {
        if ptype.is_none() {
            ptype = Some(caps["ptype"].to_string());
            continue;
        } else if Some(&caps["ptype"]) == ptype.as_deref() {
            continue;
        } else {
            panic!("one matcher can only contain one type of policy. eg. p, p2, p3...");
        }
    }

    return ptype;
}